Although the government data suggested that retinyl palmitate is carcinogenic on skin exposed to sunlight, however dermatologists did not see the evidence to support that suggestion.

The report from those dermatologists as a response of 2010 Sunscreen Guide from the Environmental Working Group (EWG; a nonprofit research organization in Washington, DC) who suggest consumer to avoid sunscreens with retinyl palmitate and use other brands without that ingredients. EWG’s suggestion also covered by many major media outlets including WebMD.

Based on analysis after looking the government data from the National Toxicology Program (NTP; a part of the Department of Health and Human Services), the lead author of study, Steven Q. Wang, MD, from Memorial Sloan-Kettering Cancer Center in New York City, and colleagues said that they have disagreement over the data.

Dr. Wang and his coauthor write that “other photoprotection practices, such as avoiding excessive sun exposure, seeking shade, and wearing photoprotective clothing, hats, and sunglasses” should “serve as the primary tactic to reduce skin cancers and minimize photoaging changes associated with UV exposure.”

However, in the sunscreen guide of the EWG’ they also write, “Limiting sun exposure and wearing protective clothing are even more important for protecting your skin from cancer and premature aging.”

They explained that in 2000, retinyl palmitate was selected for phototoxicity and photocarcinogenicity testing by the NTP.
The NTP proceeded with the testing on retinyl palmitate but the data are unpublished. Neither the NTP nor the the US Food and Drug Administration (FDA) has issued a final report on the findings, although according to the FDA the draft technical report based on those data will be available in mid-December.

Meanwhile, some of these rough data are available on the NTP’s web site; these have been reviewed by both the EWG and Dr. Wang and his colleagues.

Before delving into the NTP data, Dr. Wang and colleagues provide background on retinyl palmitate. They note that it is the storage form of retinol or vitamin A, which is “an essential and endogenous nutrient for human beings.”

Dr. Wang simplified, “Human beings already have retinyl palmitate in their skin.”
They also stress that a review of retinyl palmitate by the NTP is not damning of the compound.

The authors write, “It should be emphasized that mere selection for testing does not mean the chosen compounds are dangerous or unsafe.”

They added, “Retinyl palmitate was selected because of its widespread use in cosmetics and sunscreen products.”

According to them, it is worthy to note that retinyl palmitate has also been used as a food additive and approved for use in over-the-counter and prescription drugs by the FDA.

However, the EWG claims that the NTP data indicate that tumors and lesions developed up to 21% sooner in lab animals coated in a vitamin A-laced cream than in control animals treated with a vitamin-free cream.

According to the EWG, as part of the NTP testing, the animals (lab mice) were exposed to the equivalent of up to 9 minutes of noontime Florida sunlight each day for a year. The effects were statistically significant for all dose groups tested.

However, the EWG say that Dr. Wang and his colleagues reviewed the data in a different manner which quickly posted an online critique of the analysis from dermatologists.

The EWG write that Dr. Wang and colleagues examine only the absolute number of tumors (neoplasms) in exposed animals and they ignore data on the rate at which animals developed tumors and other skin damage.

Due to about number listing of tumors in mice, Dr. Wang defended his team’s approach and said, “this is the conventional way of showing results.”

Despite contra argument between EWG and Dr. Wang team’s, Dr. Wang believes his team’s work was well done and subject to more scrutiny than the EWG’s analysis. “The critical difference in our 2 presentations is that ours is in a peer-reviewed journal.”

In addition, they also reported that the analysis from Dr. Wang and his coauthors, Stephen Dusza, DrPh, from Memorial Sloan-Kattering, and Henry Lim, MD, from the Henry Ford Hospital in Detroit, Michigan, are free of interest conflict.

In counter, the EWG found these article-based disclosures misleading. Elsewhere, the EWG sayd, Dr. Wang and Dr. Lim have disclosed industry ties.

The EWG writes in their online critique, “Dr. Wang has disclosed that he has been a consultant to La Roche-Posay”, a company that markets sunscreens and uses vitamin A in eye creams.

The EWG added, “Dr. Lim has disclosed a consulting relationship with Johnson & Johnson (the maker of vitamin A-containing Neutrogena and Aveeno sunscreens) and La Roche-Posay.”

The EWG further points out, “Drs. Wang and Lim also volunteer on the Photobiology Committee of the Skin Cancer Foundation, a trade organization supported by the sunscreen industry. This committee sets criteria for the foundation’s Seal of Recommendation and reviews the applications of companies [asking] to use the Seal on their products. Each company seeking the Foundation’s endorsement must pay an annual $100,000 fee.”

However, Dr. Wang suggested this was overblown. He said, “we had no conflict of interest for this manuscript-no funding for this commentary.”

Furthermore, according to Dr. Wang, as part of the publication process at the Journal of the American Academy of Dermatology, the authors were required to fill out forms disclosing involvement with industry.
Referring to EWG, he said, “That’s how they found the other disclosures.”
However, the text of articles does not reveal where to access those forms.