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Sunscreen is in the news again. You have probably seen the stories. They proclaim:

Sunscreen is safe!

Sunscreen is not safe!

Sunscreen protects against skin cancer!

Sunscreen causes vitamin D deficiency!

Sunscreen ingredients get into my blood – that can’t be good!

Sunscreen is killing the coral! 

And yet, every dermatologist on the planet recommends sunscreen.

How can you know what is true and what is not? Let’s review the data.

But first, let’s go over the basics

What is sunscreen?

Sunscreens are products that help protect the skin from the sun’s harmful ultraviolet (UV) rays. There are two types of UV rays that reach the earth’s surface: UVA and UVB.

UVA are long wavelength rays that can penetrate through glass and can reach deep into the skin surface. Although these rays have traditionally been known to cause skin wrinkling, sagging and tanning, they are now known to cause skin cancer as well.  

UVB rays are shorter wavelength rays that do not penetrate as deep into the skin surface. However, they are the major contributor to sunburn and skin cancer.  

Related content: Melanoma: What You Need to Know About Diagnosis and Treatment and What You Need to Know About Basal Cell Carcinoma

What is SPF?

SPF stands for Sun Protection Factor. SPF indicates how much solar energy (ultraviolet radiation in the form of UVB rays) is required to cause sunburn on skin that has been protected with sunscreen. This is compared to the amount of energy required to cause sunburn on unprotected skin. 

Solar energy is influenced by many factors including time of day. For example, an hour of sun exposure at 9:00 am may be equivalent to 15 minutes of solar energy obtained at noon. It also depends on a number of other factors such as location, the amount of time in the sun, and weather conditions (clouds can absorb solar energy making the sun’s rays more intense on clear days).

SPF is a relative indicator of the amount of sunburn protection a sunscreen provides. As SPF increases, so does the protection from UVB rays. It is important to note that SPF labels on sunscreens are often not accurate.

An SPF of 30 prevents 97% of UVB rays from reaching the skin’s surface. An SPF of 50 prevents 98%. No sunscreen is able to provide 100% protection.

SPF does not provide information about protection from UVA rays. Sunscreens that provide protection against both UVA and UVB may be labeled “broad spectrum.”

What are sunscreen filters?

Sunscreens contain one or several active ingredients called sunscreen filters. In the United States, the Food & Drug Administration (FDA) has approved 16 sunscreen filters.

Each filter can protect the skin from different wavelengths of ultraviolet radiation. For this reason, it is common to see multiple “active ingredients” or sunscreen filters listed on the ingredient listing of any given sunscreen product.  

Sunscreen filters can be divided into two classes, organic and inorganic. The classification depends on how they prevent the sun’s UV rays from reaching the skin surface. Organic or “chemical” sunscreen filters absorb the rays. Inorganic or physical sunscreen filters, of which there are only two, titanium dioxide and zinc oxide, reflect and scatter them.

What are the different sunscreen filters?

In the United States, only half of sixteen approved sunscreen filters are actually being used today. I have marked them with an asterik (*) in the alphabetical list of filters below.

The eight approved filters that are not used have adverse properties. They are cosmetically unpleasing, cause allergic reactions, have unlikable properties, like turning the skin blue. Some are no longer manufactured.

Of the eight filters that are being used, only two can cover the UVA spectrum adequately: avobenzone and zinc oxide.

Which sunscreen filters are FDA approved? 

1. Aminobenzoic acid

Aminobenzoic acid is also well known as PABA. It is approved for use up to a concentration of 15%. It was one of the first filters used in sunscreens after its UVB absorbing properties were discovered. PABA is a “natural” chemical found in the vitamin folic acid as well in many foods like grains, eggs, and milk.

Although PABA is an effective sunscreen filter, it is also a strong sensitizing agent. In addition, in the 1980s studies showed that PABA might increase the risk of cellular UV damage. PABA is seldom if ever, used in today’s sunscreen formulations. 

2. *Avobenzone

Avobenzone is also known as Parsol1789. It is one of the most commonly used sunscreen filters in sunscreen formulations today. Avobenzone degrades in light and is very photo-unstable. Therefore is often formulated with a stabilizing agent such as octocrylene, another sunscreen filter, or stabilizing agent. It is approved for use in Europe, Australia, Japan, and in the US where it can be used in formulations up to 3%.

3. Cinoxate

Cinoxate is an approved sunscreen filter for its broad-spectrum UVA and UVB protection. It is a very ineffective filter and therefore, no longer manufactured or used in sunscreen formulations.

4. Dioxybenzone

Dioxybenzone is an effective sunscreen filter with an unfortunate side effect. When exposed to ultraviolet light, it turns the skin blue! This filter is no longer used in today’s sunscreen formulations.

5. Ensulizole

Ensulizole is an effective filter against UVB rays. It is water-soluble so it feels light and non-greasy on the skin. But because it is water-soluble, it is not water-resistant – a quality desired by consumers who are swimming or sweating from heat or exercise. This sunscreen is rarely used in sunscreens. But it may be found in daily wear moisturizers that contain sun protection.

6. *Homosalate

Homosalate is an effective sunscreen filter against UVB rays and is found is almost half of all sunscreens on the market, Homosalate is a compound that belongs to a class of chemicals called salicylates. Salicylates have an analgesic property, an ability to numb the skin when applied topically.

Although homosalate has never been approved as an analgesic. However, there is some concern by knowledgeable chemists that the use of this product may minimize any pain or discomfort that could warn the user of a developing sunburn. Homosalate has also been accused of being an endocrine disruptor and an agent that increases the absorption of certain chemicals into the skin. This filter is approved in Europe, Australia, Japan and in the United States where it is considered safe up to a concentration of 15%.

7. Meridamate

Meridamate is an effective UVA sunscreen filter that has been approved in both the United States and Australia. Meridamate is barely used in sunscreen formulations as it can cause allergic skin reactions and because it smells like bubble gum.

8. *Octocrylene

Octocrylene is an effective UVB filter. It is used to stabilize other UV filters. Octocrylene is a thick stable compound that tends to feel greasy. The maximum FDA approved concentration is 10%.

9. *Octinoxate

Octinoxate is a widely used UVB sunscreen filter. It degrades over time especially when exposed to ultraviolet light. It is approved in Europe, Australia, Japan, and the United States up to 7.5%. Octinoxate is one of two filters that have recently been banned in Hawaii as of 2021 due to its presumed damage to coral reefs.

10. *Octisalate

Octisalate is another widely used UVB sunscreen filter in the class of salicylates. It shares the same concern by experts that its analgesic properties may minimize discomfort or pain sensation from a developing sunburn. Octisalate has an oily consistency and offers a mild floral fragrance. It is approved in Europe, Australia, Japan, and the United States up to 5%.

11. *Oxybenzone

Oxybenzone is an effective UVB and partial UVA sunscreen filter. It is photostable but has recently been shown to possibly cause DNA damage when exposed to ultraviolet light. It is approved in Europe, Australia, Japan and in the United States up to 6%. Oxybenzone is the second sunscreen filter recently banned by Hawaii as of 2021 due to its presumed damage of coral reefs.

12. Padimate O

Padimate O is a derivative of the once used PABA sunscreen. This controversial sunscreen filter was shown to possibly cause DNA damage when exposed to ultraviolet light. It is no longer used in sunscreen formulations.

13. Sulisobenzone

Sulisobenzone is an effective UVB and partial UVA sunscreen filter. It can be used to stabilize other UV filters, however, it is water-soluble. Therefore it is not ideal for use in water-resistant sunscreens that are desired by swimmers and those sweating due to high ambient temperatures and exercise. This filter is not commonly used.

14. Trolamine salicylate

Trolamine salicylate is a salicylate and an effective UVB filter. It is an approved active ingredient for over-the-counter temporary relief of muscle and joint pain. It shares the same concern for diminishing the pain of developing sunburn with the other UV filter salicylates. This filter is rarely used in sunscreen formulations.

15. *Titanium dioxide

Titanium dioxide is one of only two inorganic/physical sunscreen filters approved by the FDA. It filters UVB rays as well as a portion of the UVA spectrum. Sunscreen formulations with titanium dioxide tend to leave a “white cast” on the skin. The FDA recently deemed this filter Generally Recognized As Safe (GRAS).

16. *Zinc Oxide

Zinc oxide is the other inorganic/physical sunscreen filter approved by the FDA. It  is the most broad-spectrum of all the approved filters protecting the skin from both UVA and UVB rays. Like titanium dioxide, it also tends to leave a “white cast” on the skin. The FDA recently also deemed this filter as Generally Regarded As Safe (GRAS).* Ecamsule (Mexoryl SX) is a water-soluble UVA sunscreen filter that has been approved in the United States up to 3% in limited L’Oreal formulations.

Chemical vs. physical sunscreens: Which is better?

Physical sunscreens are formulated with the approved filters titanium dioxide and/or zinc oxide only. All sunscreens formulated with any combination of the other 14 approved filters are considered “chemical” sunscreens.

Dermatologists often recommend physical sunscreens for individuals with eczema or sensitive skin and for young children. This is because the tendency to develop allergic reactions to these more inert compounds is far less than the chemical sunscreens.

Physical sunscreens, however, may leave a “white cast” on the skin. No physical sunscreens made the Consumer Reports 2019 recommended list of the best sunscreens. Although many physical sunscreens were effective, they weren’t as effective as chemical sunscreen formulations when used comparatively. None of the physical blocks provided both top-notch SPF and UVA protection. In fact, there was minimal variation from the labeled SPF. 

Now, about those news stories

1. Does sunscreen cause vitamin D deficiency?

A comprehensive review of the literature from 1970 to 2017 assessed the association between sunscreen use and vitamin D deficiency. When sunscreen is used in real-life conditions, they found little evidence that sunscreen use caused a deficiency in vitamin D. The review also stated that there was no evidence to negate current skin cancer prevention advice.

2. Do sunscreen ingredients get absorbed into the blood?

A recent study in the Journal of the American Medical Association looked at plasma concentrations of active ingredients of various types of commercially available sunscreen formulations under maximal use conditions.

All four active ingredients tested, avobenzone, oxybenzone, octocrylene, and ecamsule, were absorbed into the bloodstream. Although they were found in concentrations higher than the 0.5 ng/ml FDA threshold for potential safety concerns, the study concluded the following:

      • Further studies to determine the significance of these findings are warranted
      • Individuals should NOT refrain from using sunscreen.

3. Does sunscreen really kill coral?

In July 2018, Hawaii passed a law that prohibits the sale of sunscreens that contain oxybenzone or octinoxate, claiming that these two ingredients have a detrimental impact on marine life. In particular, they are said to cause deformed coral larvae and contributed to coral bleaching. The claims were based on a study, originally published in the Archives of Environmental Contamination and Toxicology, https://link.springer.com/article/10.1007%2Fs00244-015-0227-7.  Of note, the study was done in a laboratory using artificial seawater.

In October 2018, The National Oceanic and Atmospheric Administration (NOAA) announced that global coral bleaching was occurring. Coral bleaching is a phenomenon where the coral releases the algae that live within the coral tissue turning the coral white. Experts believe the main cause is global warming is an elevation of seawater temperature. They also believe that overfishing and pollution likely contribute to coral bleaching far more than sunscreen filters.

Terry Hughes, director of the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University, said, “The conclusion from the media is sunscreen is killing the world’s coral, and that’s laughable.” Conclusion: there is insufficient evidence that sunscreen use harms coral reefs. So before you throw away oxybenzone containing sunscreens, lobby your local politicians for practices that decrease global warming.

The bottom line question: Should I wear sunscreen?

Yes! Emphatically YES! apply sunscreen daily.

The benefits outweigh the risks!

The American Academy of Dermatology (AAD) recommends wearing a broad-spectrum sunscreen with an SPF of 30 or higher on all exposed skin surfaces.

Scientific studies show that sunscreen usage decreases the development of skin cancer. It also decreases premature aging of the skin. The benefits of wearing sunscreen on all exposed surfaces, applied liberally and daily, far outweigh any risks of doing so.

Related content

Sunscreen application is only part of a comprehensive sun protection program. It is NOT permission to seek sun or prolong your time in the sun. Limit the amount of skin that is exposed to the sun’s harmful ultraviolet rays by wearing protective clothing and hats. And, seek shade when possible.

So, which sunscreen should I use?

The BEST sunscreen is a broad-spectrum sunscreen with an SPF of 30 or higher that is used liberally, daily and often. 

For individuals with sensitive skin or for those with certain skin conditions like eczema, physical sunscreen formulations are preferable.

The average adult in a bathing suit should apply 1 ounce (a shot glass full) to cover all exposed skin surfaces. Sunscreen should be reapplied every two hours if swimming or sweating excessively for continued protection. 

The choice of using a sunscreen spray, stick or bottle is personal preference. It’s more important that an adequate amount of sunscreen is applied to obtain the SPF protection printed on the product label.

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Fayne Frey, MD
Fayne Frey, M.D., is a board-certified clinical and surgical dermatologist practicing in West Nyack, New York, where she specializes in the diagnosis and treatment of skin cancer. She is a nationally recognized expert in the effectiveness and formulation of over-the-counter skincare products, and, as a speaker, has captivated audiences with her wry observations regarding the skincare industry. She has consulted for numerous media outlets, including NBC, USA Today, and, the Huffington Post, and has shared her expertise on both cable and major TV outlets. Dr. Frey is the Founder of FryFace.com, an educational skincare information and product selection service website that clarifies and simplifies the overwhelming choice of effective, safe and affordable products encountered in the skincare aisles. Dr. Frey is a graduate of the Weill Cornell Medical College and is a fellow of both the American Academy of Dermatology and the American Society for Dermatologic Surgery.

12 COMMENTS

  1. Thank you for the open discussion and providing your comments. The best scientific exploration and fact-finding is done through constructive debate and open-mindedness to examining all perspectives. It is nice to see engaged readers and an engaged author.

    -Women’s Health Editor

  2. Thank you for your detailed commentary. First and foremost, I believe most dermatologists, myself included, would agree that further testing of sunscreen filters is absolutely necessary to determine effects of these ingredients on human health and the environment. I also believe that there is little argument regarding the ability of skin to absorb skincare ingredients, including those in sunscreens. With that being said, every scientist and physician should be aware of the concept of dose versus toxicity, that it’s not the chemical that is dangerous, it’s the dose of the chemical. Every chemical has a dose below which no adverse effects or harm occurs, where the benefits of that chemical outweighs the harm. One extra strength Tylenol (500mg) cures a headache, 14 extra strength Tylenol tablets may cause liver failure and death. Yet no one would argue that we should remove acetaminophen from all drug store shelves. It’s the dose that makes the poison, not the chemical itself.

    As for current toxicological data on endocrine disrupting chemicals (EDCs), it is severely lacking. The effects these chemicals have on endocrine pathways is unknown. Yes, some UV filters show endocrine disrupting activity, but so do flaxseeds, alfalfa sprouts and many other plants that we eat every day. Although I certainly agree that more research needs to be done on potential endocrine active substances found in consumer products, including sunscreens, creating an irrational fear of this class of chemicals based on misconceptions about EDCs should be avoided. cosmetics-05-00061.pdf

    Yes, the industry is in need of safe effective UVA ray filters. In the U.S. only avobenzone and zinc oxide can adequately protect against the UVA spectrum. However, there is substantial evidence in the medical literature that concludes the use of broad-spectrum sunscreen reduces both skin cancer risk as well as skin aging. The Skin Cancer Foundation, The American Academy of Dermatology, The Australasian College of Dermatology, The Melanoma Education Foundation, and every major dermatology organization in the United States, Australia, Japan, and the European Union, all of whom base their recommendations on the current scientific literature, concludes that the benefits or wearing sunscreen as part of a comprehensive sun protection program outweighs the risks.

    Melanoma rates are increasing, particularly amongst children, adolescents, and young adults where it has increased more than 250% in the past 4 decades. To blame UVB-biased sunscreens as the cause of this increase is irresponsible and unfounded. Mitsis DKL, Groman A, Beaupin LM, et al: Trends in demographics, incidence, and survival in children, adolescents, and young adults (AYA) with melanoma: A Surveillance, Epidemiology, and End Results (SEER) population-based analysis. 2015 ASCO Annual Meeting. Abstract 9058. Presented June 1, 2015.

    The SEER study commented that in addition to genetic factors, excessive unprotected sun exposure and the growing use of commercial tanning beds were the major culprits of this increase, not the use of sunscreens.

    Thank you for your insights. I believe we share a mutual concern for the well being of planet and each other.

    • Thank you for sharing your perspective on the subject … I agree that it is the dose and not the poison that is the problem (this is first rule of toxicology). However, if you have time to review my comments to FDA on the safety of these chemicals … https://www.regulations.gov/docketBrowser?rpp=25&so=DESC&sb=commentDueDate&po=0&s=Joe%2BDiNardo&dct=PS&D=FDA-1978-N-0018, especially the 27 page tox review, I think you might find several references interesting, especially how 6% oxybenzone and 10% octocrylene when used in formulas together produce 78 ppm of benzophenone (a carcinogen that has recently been banned in foods by FDA, listed by IARC and is listed on CA Prop 65 law), concerns that after just one hour of sun exposure with sunscreens allows enough UV into the skin that free radicals are released producing caspases (part of the melanoma pathway) and there are several reproductive effects in humans referenced as well. I believe this is why FDA is requesting carcinogenicity data and reproductive toxicology on the sunscreen actives in questions – especially oxybenzone. There are literally hundreds of publications outlining numerous reactions in many species – aquatic and terrestrial – let’s see if industry will conduct any of the studies requested by FDA. Also, there are many reasons why the melanoma rates have increased significantly all over the world – you can search the WHO 5 continent report, there isn’t a place that melanoma hasn’t increased … I do believe that sunscreens are not enough to protect anyone … sun avoidance/protective clothing are mainly the way to stop the global melanoma epidemic until better products can be developed.

    • All of your remarks about dose and toxicity have nothing to do with teratogenicity and hormone disruption in a fetus, particularly at 3-12 weeks. Please suggest how you would ever ethically carry out carry out a study on the effects of EDCs on a developing fetus. You would ask thousands of women to apply not just oxybenzone but combinations of all the PAH filters that all attain blood levels and follow their offspring for 40-60 years, and then their progeny to determine epigenetic effects.

      Human hormone receptor function has nothing in common with rodents and lower species. First, even infinitesimally low levels of exposure— indeed, any level of exposure at all—may cause endocrine or reproductive abnormalities, particularly if exposure occurs during a critical developmental window. Surprisingly, low undetectable doses may even exert more potent effects than higher doses. Second, EDCs may exert non-traditional dose-response curves, such as inverted-U or U-shaped curves. Both of these concepts have been known for hormone and neurotransmitter actions, but only in the past decade have they begun to be appreciated for EDCs.

      Effects of different classes of EDCs may be additive or even synergistic. EDCs may affect not only the exposed individual but also the children and their progeny in subsequent generations. effects may be transmitted not due to mutation of the DNA sequence, but rather through modifications to factors that regulate gene expression such as DNA methylation and histone acetylation. This is a very scary consequence and a risk that most would not wish to take.

      EDCs are proven to have a Non monotonic Dose Response Curve (NMDRC). Low-dose endocrine activity is to be expected. Low dose/response comparisons are impossible, as they occur in cells, tissues, animals and human populations in response to nutrients, vitamins, pharmacological compounds, hormones and endocrine disrupting chemicals (EDCs). Some argue that NMDRCs are not common, are not found for adverse outcomes, and are not relevant for regulation of EDCs. Under the linear dose response model, high dose testing is used to extrapolate to lower doses that are assumed to be ‘safe’ for human exposures. NMDRCs that occur below the toxicological NOAEL would falsify a fundamental assumption, that high dose hazards can be used to predict low dose safety.

      I would suggest reading Diffey’s paper on UVB-BIASED sunscreens (Diffey BL, Osterwalder U, Herzog B. Suntanning with sunscreens: a comparison with sunbed tanning. Photodermatol Photoimmunol Photomed 2015;31:307-314). Unless a sunscreen provides broad-spectrum protection with high UVA-PF values, a 2-week sunbathing vacation that avoids sunburn, using a UVB-BIASED sunscreen, can result in double the UV exposure with a greater health risk than a 10-session sunbed course. This landmark analytic photometric study proves that the wrong sunscreen – UVB-biased – may be more dangerous than tanning bed exposure. Just three days in the sun using a UVB-BIASED sunscreen would be equivalent to two trips to the tanning salon. Both exposures provide asymmetric UVA radiation to your skin. There is another cautionary aspect to this. The 2 week vacation model is extreme but not unrealistic. It is more acute and intense but consider the cumulative everyday exposure from using a UVB-BIASED sunscreen over many years. Many outdoor occupations reach or exceed the vacation exposure. Dermatologists all accept the increased risk for skin cancer from tanning bed exposure- mostly UVA 95% usually – but fail to see the similarity to transmission through a UVB BIASED sunscreens. Tanning bed exposure is mentioned in the SEER study as a factor in increased skin cancer so why not UVB-BIASED sunscreens – there being little difference in the cumulative radiation profiles.

      Another very instructive paper – a recent study from Godar et al presents intriguing data on the respective roles of UVB and UVA in photocarcinogenesis (Godar DE, Subramanianb M, Merrill SJ. Cutaneous malignant melanoma incidences analyzed worldwide by sex, age, and skin type over personal Ultraviolet-B dose shows no role for sunburn but implies one for Vitamin D3. Dermato-Endocrinology 2017, VOL. 9, NO. 1, e1267077 (12 pages) http://dx.doi.org/10.1080/19381980.2016.1267077. There was no correlation of increasing UVR doses, which represent erythemally weighted doses comprised primarily of UVB (290–315 nm) radiation, with increasing melanoma incidence for any skin type anywhere in the world. Even more of a paradox was the significant correlations between increasing melanoma and decreasing UVB dose in Europeans with skin types I-IV. Both Europeans and Americans in some age groups have significant increasing melanoma incidences with decreasing UVB dose, which shows UVB is not the main driver in melanoma and suggests a possible role for lower cutaneous vitamin D3 levels and UVA (315–400 nm) radiation. Melanoma may be initiated or promoted by UVA radiation because people are exposed to it indoors through windows and outdoors through some sunscreen formulations. Another argument to avoid UVB-BIASED sunscreens. All the ultra UVA filters are insoluble large MW filters > 500 Daltons. No permeation, better protection. There are sunscreens using bemotrizinol, bisoctrizole, and zinc oxide with a UVA-PF of 45 measured by HDRS – this is approaching the protection afforded by textiles. Compare this with 3% avobenzone at 8. Mexoryl XL (drometrizole trisiloxane) can attain decent UVA-PF values around 16-18 but it is always used with undesirable PAH filters.

      There is a tendency to focus on extinction as the amount prevented from passing through a sunscreen film. A more useful principle is to quantify the transmission or amount of harmful UV radiation that actually reaches the skin. Clothing has a UV protection Factor of 10-100 or more with uniform attenuation of the entire UVB-UVA spectrum, if made of dense material with medium or deep-color dyes or optical brighteners. Their extinction profile provides the best model for the ideal and maximally effective sunscreen. Many brand name sunscreens using avobenzone or inadequate amounts of zinc oxide that attain the FDA and Health Canada standard of a CW ≥ 370 nm still show considerable UVB bias, and allow transmission of undesirable levels of UVA (mostly UVA1 or the most damaging UV rays). This is best described as a monochromatic protection factor (MPF), defined as the reciprocal value of the transmittance, i.e. 1/T, at a particular wavelength. For a SPF 30 sunscreen the average MPF over the whole UVA I ranges varies from 1 (no protection) to 30 (equivalent to the SPF). Many sunscreens with 3% avobenzone that meet the CW of 370 nm only provide an average protection factor of around 3-5 in the UVA I range for an SPF 30 sunscreen.This means that 1/3 or more (> 33%) of the UVA I radiation is still transmitted onto the skin, whereas < 4% (3.7%)of the UVB radiation (i.e. 1/30) is transmitted through this kind of SPF 30 sunscreen. This is the hallmark of the typical brand name UVB-BIASED sunscreen dominating the market – an extreme UVB protection bias where up to 10 times more UVA than UVB reaches the skin. Asymmetric UVA exposure similar to a tanning bed- less acute and less intense but likely posing the same risks.

      There is a harmony and confluence between the first precept or sacred trust in medicine – “primum non nocere” (first do no harm) and the Precautionary Principle”, when exercised by regulators like the FDA. Eventually, the FDA will develop a regulatory framework and a new Sunscreen Monograph based on the tests that prove safety 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 and certainly the fetus, even low dose aspirin and many other OTC non-prescription items.

      Since the FDA has provided further proof of bioavailability, industry and their consultants should have no issue with a LABEL WARNING, while they work to meet the requirements to establish safety. This allows the consumer to also share the responsibility and burden of protection against harm with their regulators. An informed choice to use an insoluble mineral sunscreen that is not ordinarily bioavailable, instead of the Category III filters, avoids all the controversy and any risks, including the serious often irreversible effects from hormone disruption, and all the minor self limiting problems like photocontact allergy.

      With the FDA proposal, I would humbly suggest that all physicians begin to advise patients that permeation occurs when using A PAH filter, particularly if expectant or nursing mothers, parents of young or adolescent children, and couples trying to conceive are involved. To the skeptics about how serious the toxicity from PAH filters is likely to be, I would encourage them to exercise caution for their families and patients, and err on the side of caution to spare them the serious consequences of rubbing on these congeners of petrochemicals, DDT, BPA, and human estrogen. Health and lifestyle decisions are personal. I will exercise the Precautionary Principle every time where my grandchildren are concerned. For patients, I will continue to sustain the first precept in medicine – Primum non Nocere (first do no harm). A lot of adjectives are being thrown around – irresponsible, unfounded, irrational. Everyone is entitled to their opinion – those who are confident that there is no need for the FDA to invoke the Precautionary Principle and no need to counsel patients on permeation, should feel free to continue using PAH filters personally and professionally. Most patients elect to use insoluble filters when given the information on PAH filters.

  3. I am married to a dermatologist. She is also a photobiologist and sub-specialist in cutaneous laser surgery & medicine. In 2008 CDC in the USA reported that 96.8% of Americans had benzophenone (oxybenzone) in urine from its pervasive use in sunscreens and cosmetics She stopped recommending sunscreens using Polycyclic Aromatic Hydrocarbon (PAH) since then, when it also became apparent from earlier European studies that several of the group – oxybenzone, octocrylene, homosalate, and 4-methyl benzylidene camphor had hormone disrupting effects in animals and humans. In the EU, 85.2% of nursing mothers had at least one UV filter in breast milk (Schlumpf et al Chemosphere 2010), and oxybenzone was found in the urine (99%) and amniotic fluid (61%) of patients having amniocentesis (Philippat et al Environ Health Perspect 2013). Our review of the literature over 2 decades suggests that 6-11% of the amount applied to skin is absorbed into blood. FDA data now confirms permeation through human skin does occur, and even ecamsule with a borderline MW around the 500 Dalton mark was able to do so at a low level still exceeding the FDA threshold for toxicity testing.

    No further studies are needed in our opinion. We believe in the first precept – Primum non nocere – First do no harm. Particularly since it is now very likely that these PAH sunscreens do not have the requisite UVA protection to inhibit the UVA mutagenesis and the disabling of the repair p53 gene essential to prevent cancer. There are over 15 papers in contemporary literature that show a primary role for UVA (particularly UVA1) in the genesis of skin cancer (and photoaging). UVA also may be crucial in melanoma. Godar et al (Dermato-Endocrinology 2017) established this by showing was no correlation between UVB exposure and increasing melanoma incidence, and in some cases, there was an inverse relationship (certain ages and skin types in Europe/Italy/America). There was no difference in the incidence of melanoma between outdoor and indoor workers who are exposed to UVA through clouds, auto and window glass, and UVB-BIASED sunscreens. It explains why most UVB-BIASED sunscreens have failed to prevent melanoma. Decreasing vitamin D levels that could be a factor as it helps to kill both virally infected cells and cancer cells. This argues for more sunscreens with better UVA coverage.

    The FDA is applying the Precautionary Principle for the first time with respect to PAH UV filters. The risks from any PAH filter is shown by over 100 studies in peer-reviewed literature. Where efficacy is concerned – just look at cancer statistics in the 5 decades where these PAH filters and their UVB-BIASED products dominated global markets. Melanoma rates in the United States tripled between 1975 and 2014. Skin cancer is now the most common cancer in the USA and in N. America, and accounts for more than 50% of all human cancers. Data from the Global Burden of Disease Study 2015 reported that from 2005 to 2015 there was a 27.2% and 42.9% increase in the global death rate from melanoma and NMSC respectively.

    For safety, perhaps reading toxicology and endocrinology literature provides a different perspective that reproductive organs and central nervous system represent sensitive targets for developmental effects of endocrine active xenobiotics. Contemporary studies document widespread effects in human and wildlife from PAH UV filters and their structural analogues like DDT, BPA, and other EDCs. A 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 confirm that UV hydrocarbon filters, and other phenols like parabens, clearly change levels of virtually sex, pituitary, 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 very recent publication showed evidence that the PAH UV filters can affect the timing of puberty in boys and girls. Neonatal effects are also being reported – urinary levels of benzophenone in early and late pregnancy may delay fetal growth – girls more than boys ; Hirschsprung’s Disease, a neonatal intestinal abnormality that is derived from a failure of enteric neural crest cells migration during embryogenesis (5 – 12 weeks) is linked to oxybenzone exposure in pregnancy; and other neural tube defects like spina bifida are associated with maternal PAH exposure. Toxicity to human reproductive function is also a major concern.

    It is impossible to perform definitive studies on toxicity,mutagenic or epigenetic effects, or to assess the NOAEL (No Observed Adverse Effect Level) in a fetus. In the situation with PAH UV filters, the Benefit Risk Assessment equation has only risk to the fetus and no intended benefit. The industry will never provide evidence of human safety for PAH UV filters – for the simple reason they are not.

    Everyone should use a sunscreen as a part of overall sun protection strategy. First rule. Avoid every filter that could pollute your body. Second rule. Select one with the better UVA filters from the insoluble group- zinc oxide, bisoctrizole, bemotrizinol (both approved in Canada and the rest of the world), and drometrizole trisiloxane (Mexoryl XL).

    Permeation and bioavailability is now an established fact in humans. There is a common pathway for toxicity to humans and the marine eco-system. First PERMEATION then HORMONE DISRUPTION, DNA mutation and genotoxicity. If we humans use only large sized insoluble filters we protect human health and likely protect the coral as well.

    Not everything needs a study. Basic science can instruct us. The 500 Dalton rule establishes the probability of permeation into humans. Over the past 20 years (and now the FDA) many studies have confirmed the basic physiologic premise. All 12 Category III and ecamsule will permeate. There is another instructive often forgotten first principle from basic endocrinology – isoform function – chemicals with the same structure will act at a cellular level in a similar manner, and bind to the same receptors. Hence if oxybenzone exhibits endocrine disrupting properties, the entire group should be considered as doing so, and the Precautionary Principle applied.

    This article talks about true versus untrue. Yet it perpetuates a 20 y/o falsehood. Mineral filters DO NOT reflect and scatter UVR to any degree. Even the larger sized older pigment grade zinc oxide never physically impeded > 10-15% of incident radiation. Nikiforos Kollias PhD (biophysicist, photobiologist, medical physicist, bio-engineer, Professor of Dermatology, Harvard and University of British Columbia), spent the last 20 years of his life trying to dispel the myth – that there is a difference in the way “mineral or natural” and so called “chemical” sunscreens protect against UV radiation. 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 thicker mineral based make-up will achieve some reflection or a “barrier” effect but all sunscreens absorb photons of light in reducing sun damage. All UV filters, hydrocarbon or mineral absorb photons and use the 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. Harmful rays are converted to more benign spectra – usually heat.

    To comment on all questionable aspects of this article is not possible with the format, which creates a largely one-way discourse to the advantage of the writer. If regulators apply the Precautionary Principle and physicians practice the first precept the entire issue may be resolved. Insoluble UV filters with MW > 500 Daltons (G/mol) avoid all the controversy in humans, provide higher UVA protection against skin cancer, and may be a better choice for the coral, marine life, and the environment in general.

  4. The article was supposed to clarify truth versus misinformation Material here is dated and does not reflect the current body of science but contains the same platitudes from the dermatology/industry alliance. “Sunscreens prevent cancer”. Earlier studies supported the belief that intensive use of sunscreens increased the risk of skin cancer (Haywood et al J Invest Dermatol 2003). Possible explanation never discussed by dermatologists: Early sunscreens used UV filters with UVB and some UVA2 extinction but with minimal or no UVA1 filtering. These UVB-BIASED sunscreens still dominate the global sunscreen market. They prevent UVB effects like sunburn to varying degrees but offer inadequate protection against the most damaging and deeper penetrating UVA1 rays. Global skin cancer rates have doubled and tripled in some countries since 1960. Hardly surprising, as contemporary science suggests that UVA plays a primary role [24]. Autier from the International Agency for Research on Cancer, Lyon, France, warned in 2009 about the implications of intentional sun exposure using sunscreens with low UVA attenuation ability, to extend the duration of sun exposure. He called this ‘sunscreen abuse’ as it allowed outdoor behavior that would not be otherwise possible. Polycyclic Aromatic Hydrocarbon (PAH) UV filters even with avobenzone can only give UVB-BIASED protection. They have little chance of preventing the UVA mediated cascade of DNA mutations – 94% UVA versus 6% UVB – and most importantly protecting the repair p53 gene from being disabled by UVA.

    Whatever the reason for banning Polycyclic Aromatic Hydrocarbon (PAH) sunscreens to protect coral, there is little dispute about prohibiting their use in HUMANS. If there is little benefit to using the typical sunscreen with combinations of the proposed Category III UV filters, the whole Benefit Risk Assessment (BRA) paradigm takes on a different perspective, where any level of risk, however low, may be unacceptable.

    Earlier studies suggest that reproductive organs and central nervous system represent sensitive targets for developmental effects of endocrine active xenobiotics. Contemporary studies document widespread effects in human and wildlife from PAH UV filters and their structural analogues like DDT, BPA, and other EDCs like parabens. A 2016 review of 85 scientific papers in humans and lower species concluded that PAH UV filters are generally involved in the disruption of the hypothalamic–pituitary–gonadal system. More recent studies in 2017-2019 confirm that UV hydrocarbon filters, and other phenols (like 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. In one of several recent studies in healthy premenopausal women, various phenols, including oxybenzone and parabens changed the levels of key reproductive hormones – FSH (Follicle Stimulating Hormone), (LH) Luteinising Hormone, estradiol, and progesterone. The numerous clinical consequences are another matter, and may not be evident for up to 40 years or more. A very recent publication showed evidence that the PAH UV filters can affect the timing of puberty in boys and girls. Neonatal effects are also being reported. Maternal urinary levels of benzophenone in early and late pregnancy appear to delay fetal growth with more pronounced effects in girls compared to boys. Hirschsprung’s Disease, an uncommon neonatal problem from a failure of enteric neural crest cells migration during embryogenesis from 5 to 12 weeks.has been linked to oxybenzone exposure in pregnancy. Neural tube defects like spina bifida have been reported to be associated with maternal PAH exposure. Toxicity to human reproductive function is also a major concern.

    It is impossible to carry out definitive studies or to assess the NOAEL (No Observed Adverse Effect Level) in a fetus. for toxicity, and mutagenic or epigenetic effects. In the situation with PAH UV filters, the BRA equation has only risk to the fetus and no intended benefit. The Precautionary Principle as integrated into various jurisdictions, recognizes that the absence of full scientific certainty shall not be used as a reason for postponing decisions where there is a risk of serious or irreversible harm. The application of precaution is distinctive within science-based risk management and is characterized by three basic tenets: the need for a decision, a risk of serious or irreversible harm and a lack of full scientific certainty. The precautionary principle permits decision makers to take decisions in the absence of scientific certainty if there is a sufficiently serious risk. So it requires the exercise of judgement, in other words it is a principle of policy making.

    I will leave the debate about taking a precautionary approach for the marine habitat to the divided group of coral scientists and marine biologists. The skeptics in the marine world can afford to ignore the Precautionary Principle. I cannot. As a physician, I march to a more exacting drummer – the sacred trust in medicine – “primum non nocere” or first do no harm.

  5. Sorry, one more point. The only thing that is laughable about sunscreens harming coral is that the damage is only caused by one thing – “global warming”. Corals have been bleaching in Hawaii at 3 to 6 degrees Fahrenheit below what is normally seen with global warming. A study just published a few days ago demonstrated that nitrogen run-off plays a very important role in coral bleaching/death https://link.springer.com/article/10.1007/s00227-019-3538-9 … many sunscreen products contain nitrogen as well and too many tourists in an area can also be problematic … the list goes on. Also, it’s not just coral, many aquatic species are negatively impacted by these chemicals. No one that I have ever conducted research with ever said “if we ban sunscreens the coral will all come back”… remember doubt is the $10 billion sunscreen industry’s way of continuing to make money!

    We need to do as much as we can, as soon as we can to stop the environmental damage that is occurring everywhere on our planet … banning damaging sunscreens is just the start and it is something we can all do NOW.

    • Joe Dinardo is exactly right. Permeation and bioavailability is now an established FACT in humans. There is a common pathway for toxicity to humans 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. The finding of PAH filters in rivers, lakes, remote estuaries, coral reefs, and even in the surface and coastal waters of the Arctic, with further contamination of fish and other marine food sources, should concern all of us. It may also be a secondary route for human contamination.

      The FDA is applying The Precautionary Principle at long last, to these petrochemicals that are structural analogues to DDT, BPA, human estrogen, and numerous phenols. Physicians are remiss in not advising patients about permeation even if there was no risk of harm.

      The physicians (who are now on every media platform) denouncing the FDA Proposal, appear to ignore the fact that many EDCs are proven to have a Non monotonic Dose Response Curve (NMDRC). Low-dose endocrine activity is to be expected. Low dose/response comparisons are impossible, as they occur in cells, tissues, animals and human populations in response to nutrients, vitamins, pharmacological compounds, hormones and endocrine disrupting chemicals (EDCs). Some argue that NMDRCs are not common, are not found for adverse outcomes, and are not relevant for regulation of EDCs. Under the linear dose response model, high dose testing is used to extrapolate to lower doses that are assumed to be ‘safe’ for human exposures. NMDRCs that occur below the toxicological NOAEL would falsify a fundamental assumption, that high dose hazards can be used to predict low dose safety. Furthermore, the fact that a substance with endocrine biological activity is accepted for pharmaceutical use does not imply that its effect can be used as a comparison for other chemicals or mixtures. A substance with similar or even much lower effects on the reproductive cycle should still be regarded as an EDC when used outside an intended therapeutic purpose. While a substance that blocks reproduction may be viewed as safe as an ingredient for a contraceptive, it is clear that a reduction or loss of fertility should be interpreted as an “adverse effect” when resulting from a mixture not specifically designed for this, such as a cosmetic, PAH UV filter, or a drug with another purpose.

      Eventually, the FDA will develop a regulatory framework and a new Sunscreen Monograph based on the tests that prove safety 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 and certainly the fetus, even low dose aspirin and many other OTC non-prescription items. There is a harmony and confluence between the first precept or sacred trust in medicine – “primum non nocere” (first do no harm) when applied by physicians and the Precautionary Principle”, when exercised by regulators like the FDA.

      Not everything in clinical medicine needs a study. Fundamental physiology and first principles are instructive. All of the Category III filters share common properties. They are low Molecular Weight (MW) soluble chemicals that will be absorbed through human skin, at different rates and perhaps to different peak levels. The 500 Dalton rule establishes this probability (Bos & Meinardi 2000) and over the past 20 years many studies have confirmed the basic physiologic premise.

      The FDA proposal questions 40 years of policy. We should let consumers make their own informed choice on the fact of permeation into blood, breast milk, and crossing into our brains and the unborn. The golden rule in endocrinology is “isoform function”, same structure – same actions – where permeation and hormone disruption are concerned. For over two decades, I have said that if oxybenzone reaches blood, all PAH filters will 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.

      Think of the enormity of this : there is no other OTC, drug, pollutant, or pesticide that is found in 96.8% of humans tested, in the breast milk of 85.2% of nursing mothers tested, is present in global municipal wastewater, found in coastal waters around resorts and in remote estuaries, in rivers all over the world, in most swimming pools and hot-tubs of most resort or public pools – from North America, to Japan to Switzerland to Australia, even the Arctic – literally the entire globe when looked for, as is the case for oxybenzone and other hydrocarbon UV filters. All of this for UVB-BIASED sunscreens – that cannot and as statistics show – DO NOT prevent skin cancer to any useful degree.

  6. These are all very important points to consider: however, currently FDA has changed what is “approved”. Only Zinc Oxide and Titanium Dioxide are currently consider safe and effective for human use (Category I). PABA and Trolamine Salicylate have been removed from the FDA list because they are not considered safe and effective (Category II). The remaining 12 chemicals FDA is requesting additional testing (Category III), specifically, human absorption, what happens to the chemical when it enters your body, can it cause cancer and can it cause effects to unborn babies. These points have come up because scientists from all over the world have already published several studies that demonstrate that these risks are possible. The question is will the $10 billion a year sunscreen industry spend the money to show FDA that these 12 chemicals are safe (this is required by law, our tax $ are not supposed to be used). Short answer – NO; they hardly ever do and it is highly unlikely they will do it now. Industry will more than likely continue to cast doubt on the issue with phrases like “?sunscreens save lives?” “?sunscreens prevent skin cancer” and alike confusing as many people as possible for as long as they can, in order to make as much money selling these products before they are told to remove them from the store shelves!

    Should you use a sunscreen? If you do, you should minimize your exposure to them as much as possible by applying them to only the exposed areas! Until then, PLEASE avoid direct sun exposure when possible – especially at peak hours (10 AM – 3 PM), wear protective clothing – including hats and sunglasses, if going to the beach use a beach umbrella or cabana and LASTLY apply a non-nano zinc oxide or titanium dioxide (Category I) sunscreen to any areas exposed to sunlight.

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