EDC Infographic

The fetus is the most vulnerable human. The entire pregnancy is susceptible to external agents- viral or chemical – disrupting normal fetal development at many levels. Embryonic and fetal life in the first trimester is the most crucial period but any insult up to 20 weeks may affect anatomic, hormonal, and neurological development, or any organ system. Effects are usually more serious and irreversible when they occur in early pregnancy.

Twelve soluble aromatic  UV filters have been watchlisted by the US FDA and are all to be banned in Hawaii to protect the coral and marine wildlife, unless the US FDA eventually designates them as SAFE and EFFECTIVE. All pass through human epidermis to attain tissue levels and bathe every cell in the body. They are fat soluble and will bio-accumulate in tissue over time. They even cross the Blood Brain Barrier of your unborn or young child.   Studies confirm the widespread  contamination of humans with soluble UV filters found in blood, urine, amniotic fluid, placenta, fetal and cord blood, semen, ovarian follicular fluid, and adipose tissue. The entire global water supply, terrestrial, aquatic and marine biota are all polluted with these petrochemical UV filters. An evidenced based analysis based on this pervasive contamination supports the contention that soluble UV filters may have become the leading source of exposure to hormone disruptors, particularly in developed countries where sunscreen use is highest. Adult exposure to a chemical or hormone disruptor  may have very different consequences from fetal or infantile exposure.

Twenty five years of science prove bioavailability of UV filters to humans and wildlife, recently  confirmed by FDA studies to achieve levels exceeding the FDA threshold for toxicity testing. The FDA reiterated the concern in 40 years of scientific literature for hormone disruption and other adverse effects in wildlife and humans. They list 12 of these soluble hydrocarbon UV filters as having insufficient data to consider them  Generally Regarded As Safe or Effective (GRASE). These include avobenzone, oxybenzone, homosalate, octisalate, octocrylene, octinoxate, meradimate, cinoxate, padimate O, ensulizole, dioxybenzone, and sulisobenzone. Only the INSOLUBLE inorganic mineral UV filters zinc oxide and titanium dioxide have the evidence to support the positive GRASE category given by the FDA.

Regardless of the risks, the mere fact of bioavailability to the fetus and their presence in breast milk should be reason enough to avoid them during pregnancy and nursing. I urge every consumer to avoid them completely. Recent scientific literature confirms the same pattern and prevalence for adverse effects in humans and wildlife from organic UV filters. They also pollute the water supply and the food chain. Ingestion becomes a secondary route for human contamination. This is of particular concern when exposure occurs pre-conception, during pregnancy or nursing, in  infancy and  childhood, and adolescence or puberty. Serum and urine sampling provide a “snapshot” but may not assess the persistence of a UV filter in cells of adipose and important human tissue e.g. the brain. Testing after limited application of UV filters in some studies cannot measure relevant long-term or lifetime levels in assessing human toxicity.

There is no real evidence that these soluble petrochemical UV filters can or actually prevent skin cancer. Their use over 60 years is paralleled by sharp increases in all forms of skin cancer, particularly in young adults, moreso in females. Since there is no defined benefit provided by sunscreens using these filters, then unintended human and wildlife toxicity become more significant. Definitive fetal toxicity studies to identify mutagenic, epigenetic effects, or to assess the NOAEL (No Observed Adverse Effect Level) in a fetus are either unethical, impractical, and close to impossible. The Benefit Risk Assessment for soluble organic UV filters have little benefit to the mother in discernible population based reduction of skin cancer for the mother and  has only risk to the fetus and no intended benefit.

For all of the reasons listed above, but even from the position that prudent people will usually exercise an abundance of caution- especially where your children are concerned – we believe that all consumers should strictly avoid using these bioavailable filters. At very least, they are best avoided during pre-conception, pregnancy, and nursing – in my opinion they are absolutely contraindicated during pregnancy and nursing. Until a WARNING Label appears on these undesirable sunscreens about BIOAVAILABILITY for all consumers, with a special CAUTION to pregnant or nursing mothers and others who may bemore vulnerable, please enforce your own AVOIDANCE. The alternative – use sunscreens with large molecular weight INSOLUBLE filters – inorganic zinc oxide, titanium dioxide,  organic bemotrizinol, bisoctrizole, and drometrizole trisiloxane, which exceed the 500 Dalton threshold for permeation through human skin. This avoids the bioavailability underlying any risks for the adverse effects seen with SOLUBLE petrochemical UV filters.  These  insoluble filters  include the most efficient UVA filters and provide better balanced UVA/UVB protection against skin cancer and keeps you looking younger for longer. More BENEFIT– virtually  ZERO RISK. The Precautionary Principle applied – and a better Benefit Risk equation for  humans, wildlife and the environment.


© Denis K. Dudley MD, JUNE 2019. All rights reserved.



Mineral sunscreen applies clear

My previous blog post described why aromatic organic UV filters – all with a benzene ring and belonging to the petrochemical class of chemicals – are neither SAFE or EFFECTIVE. A recent article on CNET quoted  a dermatologist on the comparison between mineral sunscreens and those using 12 aromatic organic UV filters delisted by the US FDA. It was full of dated and inaccurate information. One astute reader commented that  “this article is written mainly to support chemical sunscreens when there is almost no reason not to use physical”. She was exactly right!! I would add that there is every reason NOT TO EVER USE organic petrochemical UV filters – wrongly called a chemical sunscreen. All UV filters are CHEMICALS – fundamental Chemistry. Some sunscreens are organic -meaning carbon based with complex carbon chains and phenolic or benzene rings in their structure.  Mineral UV filters are inorganic compounds (contain no carbon atoms) like zinc oxide, titanium dioxide, iron oxide, and others. Their individual atoms all occur on the Table of Chemical Elements. Mineral or inorganicUV filters belong to the class of INSOLUBLE CHEMICALSwith a large molecular weight > 500 Daltons, which prevents absorption and bioavailability. Organicaromatic petrochemical UV filters in the FDA category III (oxybenzone, avobenzone, homosalate, and 9 others), belong to the class of SOLUBLEUV filters with a small molecular weight < 500 Daltons, the threshold for absorption. All permeate human skin and become bioavailable to every cell in your body, even to the human fetus.

Both the article and that comment suggested that mineral sunscreens were not as esthetic as petrochemical oily filters. The comment also raised the issue of toxicity to the marine environment. Both require accurate information. Fifteen to 20,000 tons of SOLUBLE organic UV filters in popular sunscreens wash off annually and destroy our reefs, similar to an oil spill – an episodic local event, while sunscreen slicks are daily and worldwide, and can damage reefs 6-10 miles offshore. Organic soluble UV filters pollute every link in the land-based aquifer leading to the oceans.  Almost all of the 12 organic filters delisted by the US FDA are found in Waste Water Treatment Plant (WWTP)  influents and effluents, since they do not remove these petrochemicals. By  2015, thirty-three scientific publications confirmed their contamination of WWTP inflow and outflow, swimming pools, tap-water, urban groundwater, freshwater (rivers and lakes), estuaries, seawater, and  of  sediments from rivers, lakes, beach sand, soils, and sludge.

Regional  pollution of open water around coral reefs was confirmed for oxybenzone in the U.S. Virgin Islands, homosalate and oxybenzone in Japanese waters, and for oxybenzone and avobenzone in South Carolina waters. It is a lengthy exercise to reference the widespread pollution of global water. Studies document the presence of the FDA category III filters in rivers – even in the remote Swiss Alps and Australian estuaries, lakes, streams, ponds and wastewater, wherever humans use sunscreens and personal care products. Even where sunscreen use must be low – the Arctic – these filters pollute, likely from loop currents that bring them from distant coastal waters and cruise ship discharge in the Northern Atlantic.  The  ubiquitous contamination by these petrochemical UV filters of the entire global environment is confirmed by their presence in the open waters of the Pacific Ocean, the surface waters of China, Japan, the USA, Thailand, and every global coral reef system.

The presence and resulting toxicity to marine species is extensive. Coral samples exposed to even small concentrations of these compounds exhibited severe stress responses and often mortality.  Studies identify these drastic effects in scleractinian corals exposed to relatively low concentrations oxybenzone, which was identified as a skeletal endocrine disruptor in planula of Stylophora pistillata(Downs et al 2015). Studies confirm that  soluble organic UV filters bioaccumulate  in mussels, corals , crabs, shrimps, prawns, squids fish, dolphins from the coast of Brazil, incormorants from Switzerland, and in unhatched eggs of bird species from the Natural Park of Doñana (SW of Spain), confirming biomagnification of these substances. It has been confirmed that these agents have the same effects of hormone disruption in  marine species and aquatic biota, as they do in humans. Even dermatologists now admit that mineral sunscreens are safer for the environment (Schneider and Lim 2019) – ”For those concerned about emerging evidence of environmental impact of organic UV filters, based on current evidence, ZnO and TiO ‐containing sunscreens are safe alternatives”.The senior author – Dr. Henry Lim – also stated in a recent interview that he NOW recommends mineral sunscreens for use in pregnancy. I have stringently recommended mineral sunscreens for every consumer over the past 20 years, but the use of soluble organic UV filters delisted by the US FDA must be avoided by expectant or nursing mothers, young and adolescent children, and couples trying to conceive.

Regional bans of soluble organic filters were implemented to protect the reefs in Hawaii, Marshall Islands, Palau, US Virgin Islands, Key west, and the Dutch Antilles. Hawaii has now voted to institute a wider ban to include ALL 12 of the US FDA category III filters. Coral reefs acting as the sentinel organism in the marine ecosystem provide 8 trillion USD of economic benefits to humans.

Another point raised in the article is that mineral sunscreens are less desirable from an esthetic (“white residue”) or sensory feel on skin (“sticky”). One person makes the comment that issues with mineral sunscreens  are  “difficulty with rubbing in” and requiring an “ extra 30 seconds rubbing”. Mineral sunscreens aresafer for humans and our environment and some are now as esthetic as soluble sunscreens using petrochemicals, incorrectly called chemical sunscreens.

It was reported last year that  Former First Lady, Michele Obama,  used a 25% zinc oxide sunscreen, and other celebrities with dark or brown skin have said they use the same sunscreen. Venus Williams just launched as part of her “Eleven” product line, two 25% zinc oxide sunscreens – one a serum, so thin, it is dispensed by a dropper, the other a cream. Both apply clear within a few seconds. Ms. Williams states that both are great for any skin tone, and provide the high UVA protection to prevent skin cancer and photoaging.


© Denis K. Dudley MD, JUNE 2020. All rights reserved.




sunscreen doc banner

Basic physiology and scientific studies have confirmed over 3 decades that SOLUBLE petrochemical organic (carbon based) UV filters are all absorbed through human and wildlife skin. They become bioavailable and bioactive reaching every cell, neuron, and hormone receptor in the human body – causing hormone disruption, DNA mutations, and epigenetic changes.

  • 1990 – I detected two sunscreen filters – avobenzone and oxybenzone – in fetal blood samples at 32-36 weeks.
  • 1997 – Oxybenzone detected in breast milk, and Hayden et al warned about the potential risks of systemic absorption of sunscreens after topical application (Lancet 1997). In 2001 Bos & Meinardi provided the irrefutable explanation – “The 500 Dalton rule for the skin penetration of chemical compounds and drugs”. Any chemical with a molecular weight (MW) below 500 Daltons (g/mol) penetrates human epidermis to reach blood and all tissues  – albeit at different rates to attain varying peak levels. All soluble petrochemical UV filters are below 500 Daltons.
  • Many studies confirm the basic physiologic premise.  95.8% of Americans had benzophenone (oxybenzone) in urine from its pervasive use in sunscreens and cosmetics (CDC 2008). An EU study from 2010 showed that 85.2% of nursing mothers had at least one UV filter in breast milk. Oxybenzone was found in the urine (99%) and amniotic fluid (61%) of patients having 3rdtrimester amniocentesis (CDC 2012).
  • Recent studies confirm the widespread contamination of humans with soluble UV filters found in blood, urine, amniotic fluid, placenta, fetal and cord blood, semen, ovarian follicular fluid, and adipose tissue. The entire global water supply, terrestrial, aquatic and marine biota are all polluted with these petrochemical UV filters.
  • Extensive recent literature confirms the same pattern and prevalence for adverse effects in humans and wildlife from organic UV filters, which have become bioavailable through permeation or ingestion, and are of particular concern when exposure occurs pre-conception, during pregnancy or nursing, infancy and childhood, and adolescence or puberty.
  • Permeation and bioavailability in humans are now established facts, confirmed and acknowledged by the US Food & Drug Administration (FDA). My literature review, suggests that 6-11% of the amount applied to skin is absorbed into blood, also confirmed by FDA studies in levels exceeding the FDA threshold for toxicity testing. The FDA reiterated the concern in 40 years of scientific literature for hormone disruption and other adverse effects in wildlife and now humans. The FDA now list 12 of these soluble hydrocarbon UV filters as having insufficient data to support the categorization of Generally Regarded As Safe or Effective (GRASE). These include avobenzone, oxybenzone, homosalate, octisalate, octocrylene, octinoxate, meradimate, cinoxate, padimate O, ensulizole, dioxybenzone, and sulisobenzone. Only the INSOLUBLE inorganic mineral UV filters zinc oxide and titanium dioxide have the evidence to support the positive GRASE category given by the FDA.
  • Of equal concern are the widespread effects on the environment – terrestrial, aquatic and marine. There appears to be a common pathway for toxicity to humans, wildlife, and the marine eco-system. First PERMEATION then HORMONE DISRUPTION, DNA mutation and genotoxicity. Coral has an epidermis similar to human skin but less complex, and an unintended consequence of human use of soluble hydrocarbon UV filters may be the degradation of the terrestrial and marine habitats.
  • Despite 5 decades and hundreds of reports from all corners of the globe showing that the same effects occur in wildlife and in humans, there is still a chorus arguing “more research is needed”. This position is like revolving door or ‘rabbit hole’ in my opinion and ignores the first precept in medicine “Do No Harm” and the dictates of the Precautionary Principle to err on the side of caution when human health is threatened by a chemical or drug. The Precautionary Principle asserts “that the burden of proof for potentially harmful actions by industry or government rests on the assurance of safety and that when there are threats of serious damage, scientific uncertainty must be resolved in favor of prevention”. This approach is in perfect harmony with the physician’s first rule – primum non nocere” (first do no harm), particularly when faced with serious irreversible consequences from soluble bioavailable UV filters to exposed individuals and their progeny. The Precautionary Principle recognizes that the absence of full scientific certainty shall not be used as a reason for postponing decisions, where there is even minimal risk of serious or irreversible harm.
  • There is little evidence that sunscreens using soluble petrochemical UV filters – in theory or in practice – can prevent skin cancer. Contemporary science establishes UVA as a primary driver of skin cancer. Avobenzone is the only one of the 12 FDA watchlisted UV filters with any UVA filtering activity and mixtures of these filters – give asymmetric  protection transmitting up to 10 times more UVA than UVB to skin – a significant UVB bias. This inadequate UVA protection explains why using petrochemical UV filters over 60 years for sun protection parallels the unrelenting rise in global skin cancer rates, which have doubled or tripled in many countries since 1960. From 1970 to 2009, the incidence of melanoma increased by 8-fold among young women and 4-fold among young men, and in the USA, one person dies of melanoma every 54 minutes. Skin cancer is now the most common cancer in the USA and in Canada, and accounts for more than 50% of all human cancers i.e. skin cancer cases outnumber all other cancers combined. Melanoma is the leading cause of cancer death in women ages 25-30, the second leading cause of cancer death in women ages 30-35, and melanoma is the second most commonly diagnosed cancer age 15-29.
  • The cornerstone of clinical medicine and epidemiology is Benefit Risk Assessment (BRA). This analysis has yet to be applied stringently to the common use of UVB-BIASED sunscreens using mixtures of soluble organic UV filters in the face of a steady rise in all forms of global skin cancer. Sunscreen label claims are largely based on the assumption that sunscreens could prevent sunburn and by extrapolation skin cancer and other forms of sun damage. They were never preceded by the mandatory rigorous clinical research trials looking at the BRA equation and adverse effects of hormone disruption, and genotoxic or mutagenic effects.
  • Since there is no defined benefit provided by sunscreens using these filters, then unintended human and wildlife toxicity become more significant. Definitive fetal toxicity studies to identify mutagenic, epigenetic effects, or to assess the NOAEL (No Observed Adverse Effect Level) in a fetus are either unethical, impractical, and close to impossible. The BRA for soluble organic UV filters have little benefit to the mother in discernible population based reduction of skin cancer for the mother and has only risk to the fetus and no intended benefit.
  • The Endocrine Society and others document the widespread and varied effects on human health of many hormone disruptors – irreversible or in some instances transgenerational – reproductive disorders – infertility, cancers (breast, prostate, testicular), genital malformations, defects in gametogenesis, endometriosis, uterine fibroids, anddisorders of puberty – other endocrine and metabolic problems – thyroid cancer, Type 2 diabetes, metabolic syndromes and obesity, and to autoimmune and neurological problems – Alzheimer’s , Parkinson’s, ADHD, autism spectrum disorders, and childhood asthma. Reports do not single out Soluble UV Filters, but mention cosmetics as a group. Soluble UV filters have become the leading source of exposure to an Endocrine Disrupting Chemical (EDC) in developed societies where sunscreen use is highest. The germline epigenetic disorders in future generations remain unclear and will likely never be accurately defined. The fetus is the most vulnerable human.
  • Fetal effects are often serious and may be irreversible – birth weight disorders, spina bifida, Hirschsprung’s Disease (a newborn intestinal problem), issues with puberty and reproductive disorders as an adult, and problems with the early placenta leading to higher rates of miscarriage and pregnancy disorders. Whatever the risks, any prudent parent or expectant mother will exercise their own PRECAUTIONARY approach.
  • I believe that every human should absolutely avoid these petrochemical UV filters. Eventually, the FDA and others will develop a regulatory framework from valid evidence ofsafety and efficacy beyond a reasonable doubt. While it evolves, a good place to start would be with a WARNING Label on BIOAVAILABILITY and a CAUTION to pregnant or nursing mothers and others who may be more at risk – young or adolescent children, and couples trying to conceive.  This occurs for almost everything that is bioavailable to vulnerable groups, particularly the fetus, including low dose aspirin and many other OTC non-prescription items, such as vitamins, cigarettes, and alcohol. A Warning Label is justified based on the absolute proof of bioavailability, and allows the consumer to make their own informed choice.
  • The alternative – use sunscreens with large molecular weight INSOLUBLEfilters – inorganic zinc oxide, titanium dioxide,  organic bemotrizinol, bisoctrizole, and drometrizole trisiloxane, which exceed the 500 Dalton threshold for permeation through human skin. This avoids the bioavailability underlying any risks for the adverse effects seen with SOLUBLE petrochemical UV filters.  These  insoluble filters  include the most efficient UVA filters and provide better balanced UVA/UVB protection against skin cancer and keeps you looking younger for longer. More BENEFIT– virtually  ZERO RISK. The Precautionary Principle applied – and a better BRA equation for humans, wildlife and the environment.

© Denis K. Dudley MD, MAY 2020. All rights reserved.



  • NOV 2018 – Hawaii banned two SOLUBLE organic UV filters -oxybenzone and octinoxate – because of proventoxicity to coral and marine life.
  • The Marshall Islands, US Virgin Islands, Key West (Florida), the Dutch Antilles (Aruba , Bonaire, Curacao) prohibited the same two, and Pacific Palau banned 2 more UV filters, octocrylene and 4-MBC, and the preservatives – phenoxyethanol, four parabens, and triclosan.
  • FEB 2019 – the US FDA declared that ONLY zinc oxide and titanium dioxide (mineral filters) were Category I – Generally Regarded As Safe or Effective (GRASE). They watchlisted12 SOLUBLE UV filters needing more data to establish safety and efficacy for GRASE designation or Category III – cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone.The FDA affirmed 25 years of sciencethat these entered human blood (permeation) becoming bioavailable, and were toxic to humans and wildlife from hormone disruption, DNA mutation, and genotoxicity.
  • All are smaller molecules below the threshold for absorption in humans and wildlife. They become bioavailable and accumulate in humans and wildlife, mostly through permeation.
  • All are suspected or known hormone disruptors linked to birth defects, many hormonal problems and infertility, several cancers, and effects that skip this generation but affect our children and their children.
  • The risks for these adverse effects may be small and cannot be measured in the fetus, but just the fact of permeation and bioavailability are reasons to avoid them stringently.

    Before and After Healthy vs Bleached Dying Reef

The Present Situation  The sunscreen industry has deceptively capitalized by labelling sunscreens as “REEF SAFE” or “REEF FRIENDLY” if oxybenzone, octinoxate or any parabens is excluded. Yet many of these contain octocrylene – not considered reef safe in Palau. Many now use phenoxyethanol (banned in Palau) as a preservative, and labelled reef safe  to fool the consumer that a sunscreen is safe if paraben or oxybenzone free. Phenoxyethanol can be neurotoxic in humans who have occupational exposure. It acts as an anaesthetic to marine life and can be lethal to fish and coral larva.

Any reasons for banning bioavailable soluble petrochemical UV filters in sunscreens for environmental reasons must be examined in the context that they are NOT “HUMAN SAFE”. They are found in most humans (numerous international studies since 1997) – now confirmed by the FDA – at levels above the FDA threshold for safety tests, after just one day of application. Environmental studies show they pollute global water supplies – virtually every river, stream, creek, lake, and estuary of 9 countries – where studies were performed – even the Arctic. Several are found in beach sand, sediment, municipal wastewater, and numerous marine species- mussels, fish, shrimp, other shellfish, and even dolphins.

No other pollutant – Teflon, pesticides like DDT, polychlorinated biphenyls (PCB), Bisphenyl A (BPA) etc., or any drugs (prescription or OTC) is so widely distributed in humans and  all wildlife, as soluble petroleum basedUV filters. Yes petrochemicals – similar to the gas and oil you use in your car.


A TRULY Reef Safe Sunscreen – for your March Break and other Vacation Travel

  • Must also be HUMAN SAFE not using any of the 12 FDA Category III filters – cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone.Hawaii just tabled another Bill to extend their ban from oxybenzone and octinoxate to all 12 that the FDA cannot give a safe or effective rating at this time. They cited the concern for human health in addition to protecting the coral.
  • Should not contain parabens, methylisothiazilone, quaternary ammonium chemicals, any essential oils, and lime or lemon extracts that have various adverse effects.
  • Studies confirm that oxybenzone damages coral and marine wildlife by hormone disruption, just like in humans. The Category III filters will likely act in a similar manner on coral and marine wildlife as they do in humans. All bind to human hormone receptors. There appears to be a common pathway for toxicity to humans and the marine eco-system. First PERMEATION then HORMONE DISRUPTION, DNA mutation and genotoxicity. All 12 that enter humans likely pollute coral and marine wildlife by permeation at a faster rate, plus ingestion from the marine food chain.
  • INSOLUBLE larger UV filters like zinc oxide exceed the threshold for permeation and bioavailability in humans. They are the best UVA filters – more likely to prevent skin cancer. The SOLUBLE group are all UVB filters (except for avobenzone) and provide UVB-BIASED incomplete protection where 10X more UVA than UVB radiation reaches your skin, for little or no protection against skin cancer and photoaging.
  • Many marine scientists recommend mineral products as safer for coral reefs. We recommend them as SAFER for the coral, all humans plus the unborn, and our children and their children. 15-2000 tons of these FDA delisted and toxic UV filters reach our oceans every year. Oil spills are episodic and do local environmental damage unlike the invisible, insidious, daily oil “spill” from sunscreens  carried by loop currents all over the globe.
  • For definite HUMAN safety and the best option for the marine eco-system – use a zinc oxide mineral sunscreen at 20-25% – no need for titanium dioxide – more whitening on skin – and likely not good for the oceans or wildlife. Zinc is a mineral found in the ocean and in our bodies, where it acts as a co-factor in over 200 human enzyme reactions.
  • Consumers want aesthetic products that feel good on skin. Some mineral products from expert formulators are now transparentand a Former First Lady with colored skin apparently uses a 25% pure zinc oxide sunscreen. Educated consumers, especially prudent parents, will choose effective sunscreens with UVA protection affording better prevention against skin cancer and aging, with no known risks to humans, coral, marine organisms and the environment in general – best provided by 20-25% zinc oxide sunscreens.
  • The best UVA filters do not enter humans or wildlife by permeation. Zinc oxide is the best option in N. America with UV protective clothing to reduce the amount of sunscreen needed. On exposed skin use zinc oxide alone (20-25%) or with titanium dioxide (5 to 7.5%) with 15-20% zinc oxide. More efficacy against skin cancer and photoaging. Safer for humans and better for coral.  



I have said for over a decade, just about every day, that most sunscreens are neither SAFE nor EFFECTIVE. My “undesirables”  singled out for strict avoidance were avobenzone, oxybenzone, homosalate, octisalate, octocrylene, 4-methyl-benzylidine camphor, and regular (non-encapsulated) octinoxate,  present in most brand name, drug store, or doctor dispensed sunscreens. I cautioned that consumers should avoid these soluble Polycyclic Aromatic Hydrocarbon (PAH) sunscreen filters that enter blood and tissue through the skin, and are implicated as hormone disruptors and carcinogens that mutate DNA. Most parents and pregnant women are unaware of these established facts.

The FDA now agrees with me. Zinc oxide and titanium dioxide are the only two UV filters proposed to receive a Category 1 or GRASE (Generally Regarded As Safe and Effective) designation.  The FDA has placed  virtually all the PAH  filters used in typical brand name sunscreens on a “watch” list – insufficient data to support a positive GRASE  label – safety and efficacy need  to be established – to be known as Category III. These include cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone or avobenzone at this time.

While the statutory process is underway, it is very clear is that the prevailing scientific evidence led the FDA to declare that the 12 filters above, including my 7 undesirable, cannot now be considered as  safe and effective. In 2008 the Centre for Disease Control confirmed that oxybenzone, the most popular UV filter at the time, was found in 96.8 % of Americans, both genders, ages 6-70. Other studies confirmed that 85.2% of nursing mothers had one or more UV filters in breast milk, and 99% of patients having amniocentesis in the 3rd trimester had oxybenzone in amniotic fluid. The golden rule in endocrinology is “isoform function”, same structure – same actions – where permeation and hormone disruption are concerned. For two decades, I have said that if oxybenzone reaches blood, all PAH filters will do so at different rates, and take varying times to attain steady state and peak levels. The FDA did their own permeation and bioavailability studies, which confirm that all in the group (including avobenzone) attain blood levels. This led to their new proposals when they also decided that the sunscreen issue was very similar to that of BPA. I still ask  – why is there not a WARNING label on permeation and a CAUTION to pregnant women, as there is for anything sold in a pharmacy with the potential to reach the unborn.

It is still not clear whether a regulatory framework will emerge that is easy for the consumer to understand and actually leads to safe and effective sunscreens. The new generation of sunscreens must have the ultra UVA protection that contemporary science proves is necessary to prevent skin cancer and photoaging. The FDA finally accepts that better methods are needed to confirm the UVA protection afforded by a sunscreen and a BROAD SPECTRUM claim. They also discuss for the first time that many of the PAH filters like oxybenzone may be estrogenic or act as Endocrine Disrupting Chemicals (EDC), which can adversely affect human and wildlife health. They act by hormone disruption of reproductive and other endocrine systems.

The industrial alliance still argue that there is no real evidence of hormone disruption in humans.  Many physicians must not read Endocrine and human or Ecotoxicology  literature.   This literature is replete with evidence of diverse hormone disruption in humans and wildlife over the past 20 years.  A recent statement from an Australian/New Zealand Policy Group again repeated the old and inaccurate claim based on outdated studies in rodents and humans. Humans are not large rodents and endocrine receptor function in humans is unique.  A 2016 review of 85 scientific papers in humans and lower species concluded that aromatic hydrocarbon UV filters are generally involved in the disruption of the hypothalamic–pituitary–gonadal system.  More recent studies in 2018 confirm that UV hydrocarbon filters, other phenols including the preservative parabens, clearly change levels of virtually every sex hormone, pituitary hormones, thyroid hormones and certain growth factors in both pregnant and non-pregnant women. A change in a hormone level is evidence of HORMONE DISRUPTION. The numerous clinical consequences are  another matter, and may not be evident for up to 40 years or more. A 2019 publication showed evidence that the PAH UV filters can affect the timing of puberty in boys and girls. Physicians must remember the first precept or sacred trust in medicine “first do no harm”. Our regulators, policymakers, and legislators must apply the Precautionary Principle.

UV hydrocarbon filters clearly permeate into your blood and attain various levels –  reason enough to avoid them. They belong to a group of 1000 plus hormone disruptors, for which the WHO and The Endocrine Society provide scientific data showing the strong evidence for links to adverse effects in humans. These include female reproductive disorders (infertility, uterine fibroids, endometriosis, PCOS), male infertility,  reproductive cancers (uterine, breast cancer, and prostate), thyroid cancer, Hirschsprung’s disease and hypospadias in the newborn, childhood disorders (asthma, ADHD, and autism), neurodegenerative problems (Parkinson’s and Alzheimer’s disease), and metabolic disorders- obesity and type 2 diabetes.

sunscreens, endocrine disrupting chemicals
The Effect of Sunscreen Actives on Human Health at Various Stages of Development

Prudent people, especially nursing and expectant mothers, parents of young or adolescent children, and couples trying to conceive will mostly agree with our philosophy as physicians and that of the Sunscreen Company   to apply the Precautionary Principle – err on the side of caution – and the sacred trust in  medicine – first do no harm. 

It may take awhile for a sensible set of rules and enforcement to emerge and be validated by the test of time. This will become evident when the new ultra UVA sunscreens consistently prevent sunburn and   begin to lower N. American skin cancer rates for the first time. In the meantime one easy approach to use in everyday life is as follows:


  • Practice sun avoidance as much as you can. The usual caution to stay out of the sun between 10 am to 2pm is more a way of lowering your UVB exposure as UVA does not vary much with time of day or latitude. Modern science suggests that UVA is the main driver of skin cancer and photoaging. Use an ultra UVA sunscreen which will also have high UVB protection. High UVB or high SPF sunscreens may have little  UVA protection even when labelled as BROAD SPECTRUM. The new rule proposed by the FDA that UVA has to be measured not inferred and that the ratio of UVA1/UV protection has to be > 0.70 are similar  to existing EU and Australian requirements.
  • Wear sun/UVR protective clothing when outdoors and cover as much skin as you can. It is a very efficient way of providing broad spectrum protection and it reduces the amount of sunscreen you use each day. Dermatologist Sharyn Laughlin uses Solumbra™ for outdoor or vacation sun exposure – it is a tried and trusted brand of UV protective textiles. Wear a hat with a 3-5” brim and use UV protective sunglasses to shield your eyes.


  • Use SPF 25-50 but bear in mind that most sunscreens have a Real Life SPF in sunlight of 10-15 even if labelled at 50 or more. Reason – the lamp used for the SPF test emits light in a spectrum bearing no resemblance to actual sunlight. Real sunlight has 5X more UVA than the lamp. If you are very fair, assume that the SPF in popular brands may be actually only 10, and adjust your exposure time accordingly. If your unprotected skin burns in 5 minutes, only stay out for 5 times 10 = 50 minutes, and not use 30 or 50 as the multiplier for safe exposure time. The particle sunscreens with zinc oxide from do achieve Real Life SPF  closer to their label values because of the special nature of the dispersion using proprietary technology.
  • A Broad Spectrum label as regulated in Canada and the USA is likely to be untrue. Zinc oxide and avobenzone are the two common UVA filters used. 3% avobenzone or < 14% zinc oxide will only achieve a UVA-Protection Factor (UVA-PF), measured by a valid method of 5-8 – not adequate for any real prevention of skin cancer or photoaging. Avobenzone is unstable and forms nasty complexes with chlorine. I consider it an “undesirable” like its structural cousin oxybenzone. Both are now on the proposed FDA watch list. Mexoryl SX™ and XL™ are patented to L’Oreal and are good broad spectrum filters but they are always mixed with undesirables on the FDA watch list.
  • Visit for unique ultra UVA zinc oxide sunscreens with patent pending biodegradable dispersing agents that give our sunscreens better Real Life SPF and the best UVA protection in N. America. Our 25 % zinc oxide Simply Zinc Ultra (SZU) affords unmatched UVA protection for everyday as a makeup base or for outdoor and any vacation exposure. Ultra UVA protection is able to prevent the UVA damage that drives cancer. SZU achieves the highest UVA-PF of 20.4 compared with the 5 to 8 or less of virtually all the brands available in N. America. We advise all  Canadians to apply a high UVA sunscreen everyday to face, neck and back of your hands or any other exposed areas, every day in every season. A computer derivation shows that if you use a sunscreen with this level of UVA protection daily from a young age, when you are 70 years old you may look like you are only age 45. Daily application of a sunscreen like SZU is a good way to reduce your need for rejuvenation procedures, and to protect your investment after facial rejuvenation (subject for my next blog). Melanoma occurs more commonly  in white Americans and Europeans that work indoors and assume they do not need a sunscreen. For most of us, 65% of lifetime UV radiation is ambient, and not from outdoor or vacation exposure

Harm to human health and the environment, particularly the coral and marine habitat, occurs through the same pathway – first permeation then hormone disruption and DNA mutation. Visit my blog . Given the human and environmental harm from typical brand name sunscreens – there is a serious irony present. We use sunscreens to prevent cancer –  the undesirable filters give UVB-BIASED protection that cannot prevent skin cancer. They apparently do not, as global rates have doubled since 1960, despite the increasing use of these sunscreens.

Adult exposure to an EDC may have different consequences from fetal or infantile exposure. Endocrinologists use the term “the developmental basis of adult disease”, where  developing organisms – the fetus (eutherian mammals), the egg (other vertebrates), and the external environment (such as EDC exposure), interact with an individual’s genes to determine later onset of disease. The latent period may be considerable – the disease may not be apparent early in life but may only become evident  in adulthood or senescence.

Since 1991, I have cautioned that UV filters with a benzene ring resembling DDT, petroleum and other phenols, which have  estrogenic and other hormone actions – however minimal – cannot be regarded as safe for anyone.  It took the FDA over 20 years to agree with me.  Better late than never.

© Denis K. Dudley MD, FEB 2019. All rights reserved.


The ‘Winter blues’ drives 50% of Canadians towards a beach vacation and  March Break accounts for a major part of the over 85.8 million days spent by beaches (2017 Expedia® Flip Flop Report). The R&R benefit and the break from routine are positive. Most  Canadians are unaware that they contribute to coral degradation on a global scale caused by toxicity to coral and marine organisms from Polycyclic Aromatic Hydrocarbon (PAH) UV filters found  in 90% of sunscreens they use.  The world’s third-ever global coral bleaching event is now underway (NOAA). From Hawaii to the iconic Great Barrier Reef, eastward all the way to the Bahamas, Caribbean, coastal Central America and beyond — coral reefs are now being severely damaged or even dying. Coral degradation from sunscreen toxicity is  a major factor in this devastation to the coral and marine wildlife. Effects occur within a short time frame unlike the slower pace of changes induced by a rise in ocean temperatures from climate change. Coral bleaching accelerates and worsens climate change damage and devastates coral recruitment all around the world. The undesirable UV filters are genotoxic to coral larva, which greatly lowers reef generation and coral resiliency to climate change.

The common pathway for toxicity to humans and the marine eco-system.

coral bleaching, reef safe sunscreen
Living Coral vs. Dead Coral- the visible effect of coral bleaching
  • First PERMEATION then HORMONE DISRUPTION, DNA mutation and genotoxicity. Coral has an epidermis similar to but less complex than human skin. The PAH UV filters used in over 80% of our sunscreens permeate human skin to varying degrees and attain blood and tissue levels. These include avobenzone, oxybenzone, homosalate, octisalate, octocrylene, unencapsulated octinoxate, and 4-methyl benzylidene camphor (4-MBC). Studies confirm their presence in human blood, amniotic fluid, urine and breast milk.  Human contamination is not in dispute, yet Industry and most physicians (including dermatologists) ignore or deny this fact.
  • Only avobenzone has any UVA1 filtering and all the others provide UVB and some UVA2 protection. Combinations of these filters, even with 3% avobenzone as a UVA1 filter, give inadequate protection. They filter UVB to UVA in an extreme BIAS of up to 10 to 1 or more. UVB-BIASED sunscreens dominate the global sunscreen market. They prevent UVB effects like sunburn to varying degrees but cannot prevent skin cancer and photoaging to any significant degree. The unrelenting rise in global skin cancer rates support this assertion. Modern science shows that the long wave UVA1 rays are the primary drivers of skin cancer and sun damage.
  • These ineffective sunscreens  contaminate our bodies and the oceans. Numerous studies confirm their links to serious human disorders- from infertility in both sexes, uterine, breast, prostate and thyroid cancers, autism, ADHD, Parkinson’s and Alzheimer’s diseases, obesity, 5% of adult Diabetes, and  perhaps 1/3 of all cases of endometriosis and uterine fibroids in women.
  • Oxybenzone is contaminating marine environments – washing off swimmers to municipal, residential, and  the wastewater effluent from marine vessels. A 2015 report (Downs et al) confirms other studies that oxybenzone is genotoxic, kills larvae of reproducing coral, and converts the planula from a motile to a sessile state by ossification, acting as a skeletal hormone disruptor. Coral reef contamination of oxybenzone in the U.S. Virgin Islands ranged from 75 μg/L to 1.4 mg/L, whereas Hawaiian sites were contaminated between 0.8 and 19.2 μg/L. Concentrations of oxybenzone and homosalate in Japanese waters ranged from 0.5-1340 ng/L and 0.5-214 ng/L respectively. Finally, concentrations of oxybenzone and avobenzone in South Carolina waters ranged from 37.6 – 591 ng/L and 31.9 – 234 ng/L.
  • This persuasive science led to the ban of some of these toxic filters in Hawaii, Palau, and Key West. The entire group needs to be avoided in humans, if only by virtue of their permeation. The risk of permeation should a label warning on PAH sunscreens, particularly in pregnancy and for young children- just the same way there is for alcohol and cigarettes. The health risks of these estrogenic benzene compounds to all of us are considerable. They outweigh risks of BPA (bisphenyl A) banned in some countries by applying the Precautionary Principle. This precautionary and sensible approach is consistent with the first dictum in medicine – primum non nocere – first do no harm. Neither are being applied where these toxic UV filters are concerned. Label warnings of entry to our bodies might convince prudent parents to avoid them and greatly decrease their use. This would also protect the coral.
  • Numerous studies have identified significant stress responses and mortality in scleractinian corals exposed to relatively low concentrations of these chemicals, even parts per billion All will potentially permeate and harm the coral. I have been invited to join a research team at Halmos Laboratory of Natural Sciences and Oceanography (Nova Southeastern University) to study the whether avobenzone and homosalate have the same deleterious effects on our oceans as oxybenzone. It is highly probable that they will.

The Human Tragedy and Economic Consequences

There is no way to calculate the human tragedy when infertility and other endocrine disorders occur from hormone disruption caused by UV filters, even if the risk is low. In humans they represent a primary exposure to hormone disruptors in a first world modern society – now more likely than DDT, dioxin, BPA, and others. Diseases related to all hormone disruptors cost the US health care system 360 billion dollars (2014). The economic costs of destroying coral and marine wildlife are even more enormous.

  • It is estimated that 15-20,000 tons of hydrocarbon sunscreens wash off annually and destroy our reefs, similar to the way an oil spill would. Oil spills are episodic events, sunscreen slicks are daily and worldwide. The sunscreen slick can damage reefs 6-10 miles offshore.
  • 1,200 square miles of coral reefs in the United States generate more than a billion dollars per year in related benefits and business. Areas with more reef area like Southeast Asia, benefits annually from corals at 12.5 billion. Coral reefs acting as the sentinel organism in the marine ecosystem provide 8 trillion USD of economic benefits to humans.
  • The Caribbean has lost 80% of its reefs in the past 50 years mostly before 1991 and paralleled the growth of mass tourism and mega cruise ships. Reef systems in the Bahamas are showing the slow deterioration in  coral and marine wildlife over the past 30 years, not due to oil spills in the Gulf as suggested by the government. The loop current would take the contamination up the east coast of Florida. The more likely answer is the large amounts of these toxic sunscreen hydrocarbons being deposited in the coastal waters of the Bahamas by the millions of visitors in resorts and cruise ships. Resorts in Thailand (Maya Beach), the Philippines (Borocay Bay) and in Indonesia have had to shut down beaches and close hotels, because of dead coral reefs. Thoughtless mass tourism damages the local environment. Once the coral dies, the marine life leaves, and the white sand beaches disappear. Then the tourists no longer visit.

The Ironic Paradox

Sunscreens are meant to prevent skin cancer. UVB-BIASED sunscreens using soluble polycyclic aromatic hydrocarbon (PAH) filters clearly may not. Rising global skin cancer rates support this view. The global rise   parallels  the dominance of UVB-BIASED sunscreens. So these sunscreens with PAH filters pollute our bodies and the oceans and may actually be a factor in rising cancer rates.

  • Skin cancer accounts for > 50 % of all cancers in N. America – more than all others combined.  Melanoma rates in the USA tripled between 1975 – 2014, now  the leading cause of cancer death in women ages 15-30, the second leading cause of cancer death in women ages 30-35, and the second most commonly diagnosed cancer age 15-29. One person dies of melanoma every 54 minutes in N. America.
  • Global skin cancer rates rose at 3-8 % annually (The Global Burden of Disease Study 2015) It also reported that in the prior 10 years, there was a 27.2% and 42.9% increase in the global death rate from melanoma and NMSC respectively.
  • UVB-BIASED sunscreens lack the UVA protection required to prevent skin cancer and photoaging. Mineral sunscreens with zinc oxide in high concentrations, alone or combined with titanium dioxide, do not permeate human skin, avoids all the controversial effects in humans, gives better broad spectrum protection against UVA1, and is very likely  better for the land based and marine environment.
  • Most of the PAH filters and some of the undesirable preservatives used with them represent the leading causes of allergic contact dermatitis or photocontact allergy , if the reaction is precipitated by sunlight. This affects only a few individuals but it is IRONIC that most dermatologists still recommend the use of UVB-BIASED sunscreens, even if you discount the permeation and hormone disruption in humans and coral. Zinc oxide cannot cause this type of allergy, an additional advantage to its better protection and safety.

The Simple Solution

The persuasive evidence of sunscreen toxicity to coral led Hawaii in March of 2018 to ban oxybenzone, and unencapsulated octinoxate – effectively eliminating 90% of the sunscreens Canadians use at home and abroad. Palau in the Pacific Rim instituted a wider ban in November 2018 on  oxybenzone, octinoxate, 4-MBC, octocrylene, 4 kinds of parabens, triclosan, and phenoxyethanol.  Key West followed Hawaii and just approved a ban on oxybenzone and octinoxate.  A ban on ineffective sunscreens that are also toxic to humans and the environment is “low-hanging fruit”. It requires no large capital expenditure  on anyone’s part – unlike other initiatives to tackle global warming. If you stop wearing sunscreens with soluble filters like benzophenone and spread the word on social media, there would be an enormous benefit to human health. This action is a win-win. It preserves human reproductive and metabolic health – saving billions in unseen health care costs. Using mineral sunscreens can actually prevent skin cancer and photoaging. It simultaneously preserves the sanctity of our oceans, as a sanctuary for marine wildlife and a key player in the global food supply, global economics, a livelihood for millions, coastal protection, fisheries, tourism, recreation and biodiversity. 

HUMAN and REEF safe sunscreens are hard to find in resorts of the Caribbean, the Bahamas and S. Florida.

Governments and the tourism industry should lead in this important initiative.  I have approached Government ministers and resort owners in island nations and provided the scientific evidence for human concerns and pointed them to the Downs study. The silence is deafening!  The ordinary citizen can show the leadership. Make an informed choice on your March Break holiday. Avoid sunscreens that  enter your child’s body, are unlikely to prevent sunburn and skin cancer, are a primary source of exposure  to hormone disruptors, and harm the land based and marine environment. Just the fact that these benzene compounds enter blood and tissue should give you pause. Change to a mineral sunscreen – zinc oxide with or without titanium dioxide. Clear or transparent zinc oxide sunscreens using 15-25 % concentrations provide the best safe and effective broad spectrum protection. Those with < 15% are safe but do not provide adequate UVA protection to be optimally effective against skin cancer and photoaging. Our Simply Zinc Ultra, the only 25% zinc oxide dispersion available is the most protective mineral sunscreen anywhere .      

A cautionary word. Unscrupulous sunscreen companies are already using the ban on some UV filters to their advantage and deceptively market products as “Hawaiian Reef Friendly” or “Reef Safe”. If they contain any of the toxic six PAH filters – avobenzone, oxybenzone, homosalate, octisalate, octocrylene, unencapsulated octinoxate, and 4-MBC – they are not likely human or reef safe and should be avoided. They are likely to be absorbed at a faster rate by coral than they do through human skin, even that of your children. The NSU research is looking into the question of whether their similar hormone disruption in humans also extends to coral. It is more likely than not that they will act like oxybenzone and ossify the coral planula.

The industry and their dermatology partners have already started a publicity campaign to discredit the science on coral and marine wildlife toxicity, or to minimize and dismiss its significance. To them I pose this question. In the case of oxybenzone    can they name one other drug, OTC medication, pesticide, or contaminant that is present in 97% of people tested, in breast milk, amniotic fluid, and now being found widely in our rivers, lakes, oceans and municipal or cruise ship waste water? The enormity of this seems to be lost on the dermatology/industry alliance. Most politicians or hotel resort executive in the Caribbean and island nations actually pay lip service to reef conservation, and their inaction enables the environmental disaster. When the reefs die, it damages  their tourist based economies. The harm to their marine based food supply and livelihood of their citizens is inestimable.  The solution is so simple. Each of us can do this. Take a precautionary and prudent approach where the health of your family is concerned and conserve the health of our oceans at the same time. Wear UV protective clothing (like SolumbraTM) in the water. Sharyn Laughlin – dermatologist has been wearing these proven UV protective garments – she never goes south without them. Covering most of your body with UV protective clothing reduces the amount of sunscreen you use. Wear a mineral sunscreen. Both measures will be very effective reef and marine conservation. All that is required is the courage to act decisively.  Time is of the essence. Coral may be the canary in the proverbial coal mine.  It takes weeks to months for coral to die and up to 40 years or more for effects to be seen in humans.  

© Denis K. Dudley MD, FEB 2019. All rights reserved.



Media and “experts” continue to misinform consumers about sunscreens and UV protection. Facts need to be separated from fiction. This blog is dedicated to Nikiforos Kollias PhD (biophysicist, photobiologist, medical physicist, bioengineer, Professor of Dermatology at Harvard and UBC). He spent the last 20 years of his life trying to dispel the first myth –  that there is a difference in the way “mineral or natural” and so called “chemical” sunscreens protect against UV radiation.


The words “natural” versus “chemical” are used deceptively to imply that some sunscreens are not chemicals, and that a natural or mineral product might be preferable because it acts as a physical barrier  that bends or reflects light, compared to chemical sunscreens that absorb light. This has misinformed the consumer since the last century. It is repeated ad nauseam by every “expert” like a recent CBC program hosted by Heather Hiscox, where another “expert” physician said “physical or barrier” sunscreens reflected or blocked UV radiation and “chemical” products absorbed harmful rays.


All sunscreens are CHEMICALS – fundamental Chemistry. A chemical is  a  substance in any form : ionic, molecular, organic or inorganic – that is generated by or utilized in a chemical process. Some are organic – meaning carbon based with complex carbon chains and rings in their structure.  Mineral UV filters are inorganic compounds (contain no carbon atoms) like zinc oxide, titanium dioxide, iron oxide, and others. Their individual atoms all occur on the Table of Chemical Elements.


The labels physical and chemical as applied to sunscreens are inappropriate (Professor N. Kollias, Archives in Dermatology, Feb 1999). Minerals like titanium dioxide (TiO2), zinc oxide (ZnO), and others, remain as particles in a sunscreen because of low solubility. These substances are ‘physical’ since they have a predetermined particulate size but are chemicals by any definition. Even soluble organic filters will form physical crystals as the carrier base evaporates. Consumers are blitzed with the fallacy  that “natural” (mineral) filters reflect or bend light like a barrier- whereas the so-called chemical agents absorb light in a chemical reaction.


  • Photoprotection from scattering or reflection of light occurs only if a very thick optical barrier prevents  light from passing through to the skin, similar to a thick coat of paint not seen in commercially available sunscreens. This would not be acceptable to any consumer. A thick mineral  based  make-up will achieve some reflection or a “barrier” effect but all sunscreens absorb photons of light in reducing sun damage.
  • The word chemical is a misnomer as ALL UV FILTERS ARE CHEMICALS. At The Sunscreen Company TM we condemn small Molecular Weight soluble organic filters that reach blood and tissue. Organic does not mean natural or safe – only carbon based. Many of these synthetic filters contain the 6-carbon benzene ring so inimical to humans and the environment. The mineral filters zinc oxide and titanium dioxide ARE STILL CHEMICALS  – albeit inorganic –  made by a geologic system (mother earth) – hence the tendency to think of them as natural.  Mineral filters are now so processed, highly refined, milled, doped and coated that they are really “naturally derived” but so altered that  they are semi-synthetic and hardly natural.
  • New and more efficient nanoscale mineral sunscreens < 1 micron in size only scatter < 10% of incident light. Even older pigment grade forms of zinc oxide and titanium dioxide with larger molecules over 1 micron in size did not reflect more than 15% of the UV rays. All mineral or insoluble UV filters act as semi-conductors and absorb photons with electron shifts to a different valence band, so a harmful wavelength is converted to a less harmful or innocuous wavelength. New particle type filters are synthetic organic compounds that are also insoluble.
  • The only accurate classification of UV filters is soluble versus insoluble and definitely not natural versus chemical. Both types mostly act by absorbing photons. The mechanism of action in mineral UV filters involves the use of photon energy to excite electrons. For example, rutile TiO2, has a band gap energy of 3.06 eV corresponding to a wavelength of 412.5 nm. Light at or below this wavelength will have enough energy to excite electrons from the valence band to the conduction band. Any photon with a wavelength longer than the band gap will not be absorbed by the sunscreen. Each substance has its unique semiconductor properties and band gap, accounting for the filtering activity at different wavelengths.
  • Filters are safer and preferable not because of “natural” versus “chemical” but Insoluble filters like zinc oxide (inorganic) or bisoctrizole (organic) are safer since  their large size prevents entry through skin into blood, avoiding all the issues with hormone disruption and adverse effects. They are not photocontact allergens like the soluble organic filters. The best UVA filters belong to this group and provide the broad spectrum protection and high UVA shielding required to prevent skin cancer and photoaging.


Consumer Reports suggested recently that SPF retesting done by them shows which brand name sunscreens are better. They recommended as best products, several with soluble organic UV filters like avobenzone and oxybenzone, since their tests showed better agreement with the label value for SPF. The same report suggested that mineral based sunscreens like zinc oxide with or without titanium dioxide were not to be recommended as the retest SPF did not meet label claims. This is a dangerous recommendation as it may influence consumers not to use mineral sunscreens. In the right concentrations mineral products are the safest sunscreens for humans and the environment.  Along with other new insoluble UV filters, mineral agents deliver better UVA protection required for truly BROAD SPECTRUM shielding to prevent sunburn, skin cancer, and photoaging.


  • The laboratory SPF test with a solar lamp emitting a limited light spectrum compared to sunlight is useless in predicting how a sunscreen performs in Real Life sunlight for many reasons. Studies confirm  products labelled SPF 50-100 tested in sunlight are actually SPF 10-15. Professor Brian Diffey – a physicist – showed that based on laws of  biometrics and physics – most sunscreens cannot achieve a SPF above 25. FDA and Health Canada have been advised by scientists that SPF lab tests and others are accurate for lotion formulations using soluble organic filters, but are erroneous for products containing particulates like zinc oxide or titanium dioxide. The tests require modifications to accurately assess the true performance of these and other particulates. Ask any consumer if they have ever had a sunburn with mineral sunscreens using proper concentrations like 22-25% zinc oxide or 15-20% zinc oxide with a filter like titanium dioxide 7.5% or special particle dispersions. Yet 70% of fair skinned consumers may return from vacation with sunburn after applying high SPF brand name sunscreens using soluble organic filters, despite re-application every 2-3 hours and label claims of water resistance. The SPF is a fallacious test and bears no relation to outdoor performance in actual sunlight– repeating it in a different lab and comparing values just gives another useless result and cannot be used to assess the quality of a product.
  • This Consumer Report suggesting  that the best sunscreens are those using  soluble organic filters is untrue and detrimental to the consumer. The ability to prevent sunburn is one thing and the SPF may be a rough guide, but the prevention of skin cancer and photoaging depends on UVA shielding. The soluble small sized filters all enter your blood, including oxybenzone,  just banned in Hawaii because of the toxicity to coral and marine wildlife leading to severe reef degradation. The entire group are suspected hormone disruptors and may be linked to some cancers like thyroid and prostate. Worse, they give UVB-BIASED protection where the sunscreen transmits 10 times or more UVA than UVB radiation.  The UVA filter used in most sunscreens is avobenzone. It is not photostable, has a similar structure to the Hawaii banned oxybenzone – likely has similar effects – and at 3-4% in a SPF 30-50 sunscreen has a UVA-PF (UVA Protection Factor) < 10 , inadequate to prevent sun damage.
  • Proper protection approaching indoor shade and dense textiles comes from the degree of UVA protection – a UVA-PF > 10.  Higher is better and high UVA shielding usually means high UVB as well, but not vice versa. Use zinc oxide in the right concentrations and in CLEAR particle dispersions for the best UVA and BROAD SPECTRUM protection available in N. America.


Safety is the prudent first principle in selecting a sunscreen. Use ONLY combinations of these filters where  available :

  • Zinc oxide, titanium dioxide, encapsulated octinoxate, ecamsule (Mexoryl SX™), bemotrizinol (Tinosorb S™), bisoctrizole (Tinosorb M™), polysilicone -15 (Parsol SLX™), iscotrizinol, octyl triazone, and bisdisulizole disodium (Neo Heliopan AP™). None are hormone disruptors and only octyl triazone is a photoallergen.
  • Avoid them if they are combined with “undesirables” – oxybenzone, avobenzone, homosalate, octisalate, octocrylene, regular octinoxate (not encapsulated), and 4-methyl benzylidene camphor – all small molecular weight filters that pass into blood, are suspected hormone disruptors, photocontact allergens, and likely degrade coral through hormone disruption.

Good filters like bemotrizinol, bisoctrizole, ecamsule, drometrizole, and bisdisulizole are of limited availability in Canada and the USA, and even abroad are usually combined with the “undesirables” and best avoided. Adequate filter levels is the second selection principle to ensure enough UVA protection and truly BROAD SPECTRUM protection.  Zinc oxide is the only safe and effective UVA filter widely available in N. America. Look for 15-25% with or without UVB filters like encapsulated octinoxate or titanium dioxide. Any sunscreen with < 15% zinc oxide hardly achieves the UVA shielding needed to prevent skin cancer and photoaging. My next blog describes:

  • How to ensure your sunscreen has good UVA protection
  • Why high UVA shielding mimics ideal protection from indoor shade and tightly woven clothing.
  • Why high UVA shielding will prevent skin cancer and photoaging.
  • Why CyberDERM sunscreens provide the best UVA shielding in very transparent esthetic products with the best sensory feel on your skin.

© Denis K. Dudley MD 2018. All Rights Reserved.


North American consumers should not rely on label claims – whether it is the SPF or claims of UVA and Broad spectrum protection. Most of our brand name sunscreens would not pass European or Australian criteria for UVA-PF (UVA- Protection Factor) and their better standards for Broad Spectrum coverage. Proper and adequate UVA protection may be the most essential property for a sunscreen to actually prevent skin cancer and photoaging. The global market, particularly in North America is dominated by UVB- BIASED sunscreens with inadequate UVA protection, despite label claims saying ‘BROAD SPECTRUM’ UVA/UVB. Even the EWG (Environmental Working Group) recognizes this reality in their 2017 Sunscreen Report. More on this in my next BLOG.
There are over 25 stakeholder and professional coalitions with Comprehensive Cancer Control (CCC) plans  that publicise a prevention strategy. Language may differ but they all focus on key elements of sun avoidance, never burn or tan from UV exposure, wearing protective clothing with a tight weave, wear UV protective sunglasses, and generously apply a sunscreen with sun protection factor (SPF) 15 or higher and both UVA/UVB protection. Sunscreen use is the weakest link in the protocol. Rising cancer rates show that the current approach has failed and critical analysis argues that ineffective UVB-BIASED sunscreens dominating the N.American market are a driving factor.  Australia where balanced sunscreens using better UVA filters are plenty,  are actually seeing skin cancer rates levelling off or falling in certain provinces. Two landmark studies from Australia show that effective sunscreens applied daily can potentially reduce all forms of skin cancer. In N. America the grim reality is otherwise:


  • Skin cancer is now the most common cancer in the United States with the incidence essentially doubling for all skin cancers in 40 years,  and they now account for more than 50% of all human cancers – i.e. skin cancer cases outnumber all other cancers combined.
  • In 2017, over 160,000 Americans are expected to be diagnosed with melanoma, which is the leading cause of cancer death in women ages 25-30 and the second leading cause in women ages 30-35.  In ages 15-29, melanoma is the second most commonly diagnosed cancer. From 1970 to 2009, the incidence of melanoma increased by 8-fold among young women and 4-fold among young men. In the USA, one person dies of melanoma every 54 minutes (almost 10,000/year).  4000 Americans die in a year from Squamous Cell Cancer (SCC) .


Preventing sunburn (early effect) or UVA damage (early and late effects), and damage to the genetic and immune apparatus of the skin is the essence of effective photoprotection. The label SPF is supposed to quantify a sunscreen’s ability to prevent that early sign of sun damage. The SPF as measured by FDA and Health Canada mandated tests give a poor estimate of the sunscreen’s actual performance in sunlight.
The premise that SPF can be used to plan your exposure time is based on several invalid assumptions. Recent studies confirm that the lab or label SPF is inaccurate, when compared to the real life value obtained in sunlight. The lamp used in calculations for label purposes, only emits 290-400 nm based on the false assumption that the erythema reaction was mediated only by UVR (UVB and UVA). Visible Light (VL at 400-740 nm)) and Infra-red (IR at beyond 740 nm)) could be responsible for up to 20-30 % of the erythema response. Sunlight has more UVA (up to  5X ) than the testing lamp emission. Industry and physicians continue to advise consumers that the SPF can be used to calculate the safe exposure time for protected skin outdoors. We know differently –  fair individuals mostly get sunburned with prolonged outdoor exposure or during tropical vacations, despite using high SPF sunscreens and stringently following all the re-application instructions.   Media reports in 2015-2017 from Consumer Reports, the BBC in the UK, CBS, NBC, and CNN in the USA, have all presented data that up to 50% of brand name sunscreens fail to achieve even 50% of their labelled SPF values.
Science now confirms this travesty. The label SPF is inaccurate when compared to the real life value obtained in sunlight. A landmark study  presented at the 26th Annual Meeting of The Photomedicine Society (Orlando, Florida, February 2017), showed that  50 commercially available sunscreens with label SPF 50 or more had SPF values of 6-10  when measured in sunlight (Hughes S. and  Cole C.). No wonder, as testing lamp emission spectrum is far removed from that of actual terrestrial radiation, and the intensity used in testing is different from sunlight. The compliance factor also adds another real life problem as most  users apply < than the 2 mg/cmas done for the lab test. Scientists also now provide the principles in physics that explain why the SPF test cannot be accurate (Diffey B, Osterwalder U, 2017).  They report that labelled SPF, determined by in vivo assay using a UV solar simulator, overestimates the SPF that would be expected in natural sunlight.  Products labelled SPF50+ may not be able to achieve a protection against sunlight of more than 25-fold., or SPF 25. The popular interpretation of the SPF to mean how much longer skin covered with sunscreen takes to burn in sunlight compared with unprotected skin, can no longer be defended.
Any falsely high SPF reading can be further  manipulated by adding anti-redness agents (similar to aspirin) that artificially increases the MED (Minimal Erythema Dose) used to determine the SPF, for the sunscreen containing these anti-inflammatory chemicals. Sunscreens are replete with SPF boosters- bisabolol, niacinamide, salicylate compounds, and numerous others. This may be very harmful to a consumer. The false (often high SPF 50-100) values distort the reality of what protection to expect. If you are very fair – Type 1- always burns never tans- you may actually burn within 5 minutes with extreme sun exposure. An SPF 30 conveys the impression that it is safe to stay out for up to 150 minutes and SPF 50 for up to 250 minutes. A real life SPF 10 in sunlight means you should multiply your 5 minute burn time by only 10 for a safe 50 minute exposure, then get out the sun or re-apply your sunscreen liberally if you stay out longer. A boosted SPF is falsely elevated by interfering with the biologic endpoint or early warning signal of redness, the first sign of sunburn. It is no longer commensurate to the amount of radiation being prevented from reaching your skin,  but related to delayed redness. You are actually burning but have no way of knowing this as your early warning signal has been blunted. This false sense of security may make you remain outdoors i/o seeking shade. You will experience more sun damage and incur the risks of skin cancer and photoaging. This  is only related to UVB exposure – think of the damage resulting from the more harmful UVA radiation that you are now receiving in high levels, particularly since most N. American sunscreens have inadequate UVA-PF values.
  • Use no more than half the label  SPF when calculating your outdoor exposure time, and if you are redhead or extremely fair use a factor of 10.
  • It is better to use the other elements of a photoprotection strategy – avoid sun exposure, wear UV protective clothing, wear head gear and UV protective sunglasses etc. – to the extent you can, and use a sunscreen with a safe UVA filter like zinc oxide in adequate concentrations.
  • The particle type sunscreens that use zinc oxide, titanium dioxide, encapsulated octinoxate, drometrizole trisiloxane (Mexoryl XL™), terephthalylidene dicamphor sulfonic acid (Ecamsule or Mexoryl SX™),  biscotrizole (MBBT or Tinosorb M™), bemotrizinol (BEMT or Tinosorb S™),  and others are large in size, sit on the skin avoiding any entry into blood and the various attendant risks. Only the first five are available in Canada. Mexoryl XL™ and SX™ are patented to L’Oreal and regrettably are usually combined with undesirable soluble hydrocarbon filters, which should be stringently avoided. All except titanium dioxide and encapsulated octinoxate are UVA filters, and when mixed with other safe UVB filters achieve dispersions of spectral homeostasis (balanced UVA/UVB protection). In this situation where a sunscreen behaves like a neutral density filter, the label SPF may be closer to the Real Life SPF value in sunlight.  Look for products that have > 20% zinc oxide alone, or 15 % with 7.5% titanium dioxide or encapsulated octinoxate.
  • For maximum protection and to avoid all the controversy on hormone disruption and environmental hazards, use only sunscreens  with particle based or large molecular weight filters in the right combination. The high UVA protection achieves that flat balanced protection where the ratio UVA-PF/SPF approaches 1, and the label SPF comes closer to the Real Life value in sunlight. Strictly avoid all small molecular weight soluble hydrocarbon filters – avobenzone, oxybenzone, homosalate, octisalate, octocrylene, regular octinoxate, and 4-methylbenzilidene camphor. All may enter blood and only avobenzone has any UVA attenuation. It still gives a significant UVB bias where up to 30% of UVA between 340-400 nm – the most damaging UV rays are transmitted to your skin.
© Denis K. Dudley MD, October 2017. All rights reserved.


Hormone disruptors or Endocrine Disrupting Chemicals (EDCs) have been in the news again. At The Endocrine Society Meeting  (2016) , a Danish study (Skakkebaek et al) confirmed that 13/30 UV filters tested or 45%  had direct effects on human sperm cells explaining the male infertility associated with sunscreens. They imitated the hormones progesterone and prostaglandin, not estrogen, as is usual. They disrupted numerous functions required for fertility by simulating hormonal signals controlling the CatSper ion channel for calcium flux – a very specific mechanism for human sperm cells. Eight  of the 13 offending sunscreen agents are still used widely in N. America.

The response from the dermatology/industry alliance was swift and predictable. Many dermatologists appearing in the  media, are consultants for the sunscreen industry. A NYU dermatologist and consultant for Johnson & Johnson immediately proclaimed that this was not science, as it was done in a test tube. That is so absurd- many studies are done in vitro and there are already  numerous studies in vitro and in vivo in animals and humans that identify several UV-filters as endocrine disrupting chemicals. There is already enough science implicating hormone disruptors in human endocrine disorders that any human study would never be ethical. He also said that dermatologists must only pay attention to the “known science”. “The most important thing to remember is we do this experiment with tens of millions of people every summer [as they wear sunscreen on our beaches and outdoors], and we’re not seeing effects that would be predicted by a study like this.”  This is even more bizarre. As a physician, I am embarrassed at these ridiculous statements. These consumers are not being followed over a lifetime with semen analysis and epidemiologic studies looking for all the possible effects like fibroids, endometriosis, uterine cancer, breast cancer, diabetes, obesity, and several childhood disorders.  A definitive study would require  a large number of participants from pregnancy through childhood to adult ages- followed over a lifetime to see what the differences in reproductive and cancer outcomes were. Such a study is obviously impossible.

The Danish study also showed that the effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens. It  provides a context and an explanation for a prior report from the National Institute of Health that men with high exposure to UV filters like oxybenzone had a 30 percent reduction in fecundity, the biological ability to reproduce. Lower fecundity may result in a longer time to pregnancy. “Our next step is to figure out how these particular chemicals may be affecting couple fecundity or time to pregnancy—whether it’s by diminishing sperm quality or inhibiting reproduction some other way.” said Germaine Louis, Ph.D., director of the Division of Intramural Population Health Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The data came from the Longitudinal Investigation of Fertility and the Environment (LIFE) study, established to examine relationships among fertility, lifestyle factors, and exposure to environmental chemicals.

Most dermatologists like the J&J consultant, are either unaware of, or choose to ignore  the WHO and Endocrine Society positions and the prior NIH report. The WHO published a 250 page evidence based review entitled “ State of the Science of ENDOCRINE DISRUPTING CHEMICALS 2012 “ representing a broad scientific consensus among the leading experts in related fields, confirming how things have changed in just over a decade. In 2002 the scientific consensus was that there was only weak evidence for causal links existed but that careful study and observation was necessary.  Ten years later the WHO/UNEP report cite numerous examples of human and wildlife effects that call for focused action on this growing problem. “Of special concern are effects on early development of both humans and wildlife, as these effects are often irreversible and may not become evident until later in life.

For the past 10 years, I have urged physicians and patients to realize that sunscreens and cosmetics represent the major source of exposure to hormone disruptors for most urban dwellers in N. America. Consider my deductive but evidence based argument outlined below. I respectfully submit it is persuasive. Consider it in the context of the level of caution you exercise where the health of your children is concerned.

 Soluble UV filters definitely reach human blood, tissue, and regulatory brain centers through the skin

This is not theoretical as stated by dermatologists in The Globe and Mail newspaper. Basic science tells us that any fat soluble chemical with a molecular weight (MW) < 500 Daltons will pass through the skin very rapidly. The soluble filters still used in most sunscreens in this category include: avobenzone, oxybenzone (benzophenone), homosalate, octisalate, octocrylene, octinoxate (non-encapsulated), and 4-methyl benzilidene camphor (enzacamene). No study is needed  to tell me that all of these are more likely than not to enter our bodies, and reach the unborn at every stage of pregnancy. No study is needed to know that the entire group are hormone disruptors, based on the principle of isoform function, where chemicals with similar structure bind to the same endocrine receptor and produce the same effects. Since  oxybenzone and homosalate are proven hormone disruptors, so are avobenzone and octisalate. The Danish study (2016) on altered sperm function indicted all of the above plus a few others.

  • 8 studies I know of  confirm  that UV filters of this type attain blood levels in humans, not from animal studies. They come from diverse populations in the USA, France, Denmark,  Switzerland, and Sweden. A few especially refute the propaganda from the dermatology/industry alliance:
  • The CDC study from 2008 (Calafat et al) that showed 97% of 2517 Americans, age 6-70, of both genders had oxybenzone in their urine, and also found Bisphenol A (BPA) in 93.8% of these urine samples.
  • An EU study from Krause et al (2012) showing that 85.2% of European mothers had various UV filters in breast milk . 100% of the breast milk samples had pesticide residues- persistent organochlor pollutants (POPs), i.e., organochlor pesticides and metabolites, polybrominated diphenylethers and polychlorinated biphenyls (PCBs). This tells us that human contamination is related to the route of exposure. Pesticides contaminate the environment, water, and our food chain. Everyone is susceptible in certain countries. Not everyone uses a cosmetic or a sunscreen – hence the lower rate of breast milk contamination.
  • Zhang et al (2013) showed that benzophenones appear in paired urine and blood samples in adults , children, and pregnant women. Matched maternal and fetal cord blood showed that benzophenones crossed the placenta.

Hormone disruptors are definitely affecting the health of this and the next generation.

Drs Dudley and Laughlin
Dr. Dudley and Dr. Sharyn Laughlin at a company event


I am married to dermatologist/ photobiologist Dr. Sharyn Laughlin ( We share the concern of the WHO, the United Nations Environmental Program, The Endocrine Society, The European Pediatric Society, The European Commission and others, that hormone disruptors are now strongly linked to adverse reproductive outcomes, endocrine cancers, and neurological disorders like ADHD, possibly Autism Spectrum disorder, Parkinson’s disease and Alzheimer’s, asthma, obesity, and diabetes.

Consider the statement from a 2009 review from The Endocrine Society : The evidence for adverse reproductive outcomes (infertility, cancers, malformations) from exposure to endocrine disrupting chemicals is strong, and there is mounting evidence for effects on other endocrine systems, including thyroid, neuroendocrine, obesity and metabolism, and insulin and glucose homeostasis.

Their recent warning (September 2015) is even more ominous:

  • Unborn children are particularly at risk when exposed to endocrine disrupters, according to the society.
  • The new statement corroborates earlier findings, linking endocrine disrupters — in addition to their impact on obesity and diabetes — to effects on male and female reproductive health, hormone-related cancers, prostate conditions, thyroid disorders, and neuro-developmental issues.
  • Andrea Gore, PhD, Professor and Vacek Chair of Pharmacology at the University of Texas at Austin, and Chair of the Task Force that developed the statement, said the group is highlighting obesity and diabetes this time because the evidence for effects on these diseases is much stronger than it was 5 years ago. She advises that not just endocrinologists, but general practitioners, pediatricians, obstetrician-gynecologists, and fertility doctors should emphasize reduction of exposure to these disrupters when they talk to their patients.

 My comment:  Dr. Gore, like the WHO and others, has  also missed  that dermatologists and sunscreens are at epicenter of the problem. Given the patterns of exposure and the way EDCs intersect with our daily lives, sunscreen filters and cosmetic chemicals are the likely primary source of exposure for most of us in a developed society.

Why sunscreens and cosmetics are the main exposure to EDCs for most urban residents in N.America.

Over a 1000 chemicals are now identified as EDCs. Most have never been studied for their effects on humans. The ones that likely intersect with our lives include:

  • Persistent organochlor pollutants (POPs) in pesticides and flame retardants in furnishings
  • Bisphenol A (BPA) and phthalates in cans, plastics and the ink on some receipts
  • Soluble sunscreen filters and cosmetics
  • Metalloestrogens: aluminium, cadmium, antimony, selenium, tin, copper, lead, arsenite, nickel, copper, lead, cobalt, antimony, and arsenite
  • Various phytoestrogens – flavones, soy, isoflavones, favonols

Many are weak and of less significance than pesticides and UV filters. Some contaminate our food and water supply. However, the principle of multiplication is an increasing issue where an individual may be exposed to several sources. Bisphenol A  (BPA) and phthalates in plastics and tins, and produce sprayed with pesticides are publicised as a source of human EDC exposure by ingestion. This exposure is more tangential than sunscreen or cosmetic chemicals. The liver may metabolize and ameliorate the effects of EDCs ingested. Sunscreen chemicals absorbed through the skin obtain direct access to tissues and the brain and bypass this protective mechanism. Logical and critical thinking leads you to the unavoidable conclusion that sunscreen and cosmetic chemicals are the most important source of EDC exposure in a first world society.  They may be used one or more times daily in combinations of products, applied to a part of or the whole body, passing directly into the blood and brain. Soluble filters do require re-application every few hours for outdoor exposure and swimming. They wash off more easily and as they are absorbed into blood they require replacement on the skin. Particle type insoluble filters have no percutaneous entry and can be made into bioadhesive dispersions that may  not require re-application.

Linda Marsi in the October 2015 issue of MORE magazine and experts like Dr. Gore talk about reducing your exposure by avoiding storage or microwaving food in plastic containers with known EDCs, not handling receipts where ink contains phthalates, avoiding household exposures from flame retardants and stain or water repellants. Every precaution is worthwhile, but these are mostly low level and extraneous sources. Any benefit  from these precautions are negated if you ignore the greater exposure that comes from applying a cosmetic or sunscreen to large areas of skin. Many experts warn about avoiding EDCs but the silence on EDC exposure from soluble sunscreen filters is deafening:

  • After the NIH reported the data from the LIFE study on the link between infertility and benzophenone type sunscreens, infertility experts expressed concern that BPA and phthalates are a concern to all couples wishing to conceive, with the caveat that the growing body of evidence that EDCs adversely affected reproductive capacity was  “ preliminary”. Dr. Ruth Lathi, a researcher and director of Stanford’s Recurrent Pregnancy Loss Program and Dr. Linda Giudice, president of the American Society for Reproductive Medicine and a professor of reproductive sciences at the University of California at San Francisco recommended the half-measures that couples wishing to conceive should not store or microwave food in plastic containers with BPA.
  • Germaine Louis , Ph.D., director of the Division of Intramural Population Health Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development was involved with the LIFE study. She said “Our next step is to figure out how these particular chemicals may be affecting couple fecundity or time to pregnancy—whether it’s by diminishing sperm quality or inhibiting reproduction some other way.” Dr. David Adamson, founder and CEO of Advanced Reproductive Care, Inc. (ARC), the largest network of fertility specialists in the United States and a pioneer in reproductive medicine joined Dr. Louis in advising that  men concerned about fertility should reduce their use of benzophenone UV filters—and  by washing after returning indoors.

The analysis and advice in these statements is incomplete. I repeat that no one, including couples hoping to have a child, needs to moderate their use of sunscreens. The proper advice is to avoid all soluble filters. Everyone should use sunscreens with safe insoluble particle based filters that actually provide better balanced UV attenuation with higher UVA protection. Washing off benzophenone or any soluble filter at the end of the day is ineffective and illogical. Absorption is rapid, peaking  at about 10% of the applied amount, 1-2 hours after each application. If  tangential exposure from BPA and phthalates in cans and plastics pose a level of exposure to be considered, then  daily recurrent exposure from soluble UV filters and cosmetics is a greater concern. Most city dwellers in N. America have little if any exposure to pesticides, unlike the third world where indiscriminate pesticide use may explain higher rates for precocious or early puberty in girls as young as age 6-7.

My Final Thoughts

The WHO, UNEP, European Commission, European Pediatric Society, The European Environmental Agency, The Endocrine Society and The Pediatric Endocrine Society USA based), all agree the evidence for adverse reproductive outcomes (infertility, cancers, malformations) from exposure to endocrine disrupting chemicals is strong, and there is mounting evidence for effects on other endocrine systems, including thyroid, neuroendocrine, obesity and metabolism, and insulin and glucose homeostasis:

  1. In Females- uterine fibroids, endometriosis, uterine and breast cancer, infertility, polycystic ovarian syndrome (PCOS), precocious puberty, and premature menopause.
  2. In Males: prostate cancer, feminization syndromes (testicular dysgenesis).
  3. In children: asthma, learning/behaviour disorders (ADHD, autism spectrum disorder).
  4. In both genders: thyroid cancer, type 2 diabetes, obesity, cardiovascular disease, Alzheimer and Parkinson disease.

The dermatology/industry alliance cites irrelevant studies that the toxic doses in rats or mice would not ordinarily be attained in humans from the usual pattern of everyday use. The Danish researchers (Skakkebaek et al) in their 2016 study, found that 13, or 45 percent, of the 29 UV filters tested induced calcium ion influxes in the sperm cells, thus interfering with normal sperm cell function. “This effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens said. Some studies in animals do suggest that UV filters are not harmful. It is difficult to prove a negative. What is needed is proof that they are safe in humans, as we are not large rodents. Mothers with high levels of oxybenzone in their bodies were more likely to give birth to underweight or small for gestational age baby girls (Wolff 2008).  This is not a perfect study but consider if it should be ignored because a study on uterine weight in mice suggested no hormonal effects from UV filters. Most of the data from animal studies suggest that UV filters affect a variety of reproductive and other hormones. The most blatant flaw in the industry disingenuous position is that endocrine receptor function in humans is different from lower animals. Consider the potential effects on a 10-week old human embryo from even a few hormone disruptors binding to even a few receptors. The effects at this critical period of human development on endocrine function and imprinting, or on neural signaling mechanisms that are hormone sensitive, could be very profound and usually permanent.

 The developing fetus and young or pubescent children are the most vulnerable humans, since infinitesimally low or undetectable, indeed any level of exposure may cause hormonal reproductive defects, particularly at these critical times of development. The existing animal model data and human evidence taken together, suggest that exposure to EDCs during these critical times plays a role in the increased incidences of the human diseases listed above. The definitive human study over a lifetime can never be done, given the complexity imposed by varying effects due to different ages at exposure, a latent period that could be 20-50 years, multiplication from exposure to several EDCs, transgenerational  effects through altered enzymes that affect genes, confounding factors like other causes of these diseases, and the ethical dilemma since there is already strong evidence of adverse effects. We believe in The Precautionary Principle, as mandated under Canadian law, to err on the side of caution, since it meets our personal approach to medical practice and the first precept in medicine- primum non nocere or “first do no harm”. Physicians have a duty of care to advise patients that soluble filters enter blood, particularly in pregnancy, just as they do for any medication, even aspirin. Every expectant or nursing mother and parent, deserves to make their own informed choice:

  • Either: use a sunscreen with filters and chemicals that give incomplete protection, contaminate your body, and are strongly linked to serious permanent disorders, other temporary problems like photocontact allergy in humans, are harmful to lower species and damage the coral reefs as they wash off swimmers.
  • Or: exercise an abundance of caution or the precautionary approach by selecting a sunscreen with filters that remain on the skin, give arguably better or balanced protection, never attain blood, fetal, or brain levels, and have no risk for even minor adverse effects like photocontact allergy, or pose any risk to animals or the environment.

As a former obstetrician, I appreciate the persuasive simplicity that anything safe to use in pregnancy is safe to use for everyone. Dr. Laughlin describes an effective sunscreen as one that actually prevents skin cancer and photoaging. Coming from Maternal Fetal Medicine, I define a safe sunscreen as one that is safe to use in pregnancy. Soluble filters operate almost exclusively in the UVB and shortwave UVA2 wavelengths. Only avobenzone has any UVA1 attenuation. The usual combination of soluble filters provide a potent mix of hormone disruptors while providing UVB-biased protection that hardly lowers the risk of skin cancer and photoaging- mediated mostly by UVA1. Rising cancer rates are related to these UVB-biased sunscreens that dominate the N. American market. Particle based sunscreens with zinc oxide alone, or with titanium dioxide or encapsulated octinoxate meet both objectives- safety and efficacy. It is ironic that the sunscreens with soluble filters have limited benefits while probably exposing you to harm. The prudent choice seems rather obvious, but most consumers are never given the relevant information. Physicians have a duty of care to advise you that soluble filters enter your blood, particularly if you are pregnant or the parent of young or pubescent children.

The Precautionary Principle considers the limits of science and errs on the side of caution, so that action in the public interest is not delayed until the damage is done. Regulators at the FDA and Health Canada, often act only when there is incontrovertible evidence of harm, which is too late. This policy is illogical since it is criminal or unethical to do definitive studies on humans, particularly in pregnant women and children. This shifts the burden of protection against harm through caution, from the government to you. BPA was justifiably banned under The Precautionary Principle as a carcinogen and hormone disruptor. I believe The Precautionary Principle is being ignored where soluble sunscreen filters are concerned. The case for banning them is much stronger than that of BPA.

Can Using a Sunscreen Be Worse than Using a Tanning Bed? The Health Implications of a UVB Biased Sunscreen.

The Role of Long Wave UVA in Skin Cancer

There is an unrelenting rise in skin cancer rates in North America with an annual increase around 2-3 % over the past 3 decades. Continue reading Can Using a Sunscreen Be Worse than Using a Tanning Bed? The Health Implications of a UVB Biased Sunscreen.