Your sunscreen is supposed to protect you from damaging UV rays, right? According to the Environmental Working Group (EWG), however, which put out a safe sunscreen guide this year, if the ingredient list contains “retinyl palmitate,” the formula may actually be encouraging the formation of malignant, potentially cancer-causing cells in the skin.
How solid is the science behind this claim? Should you be avoiding retinyl palmitate in your sunscreen formulas? What about your other skin care products that contain this ingredient?
If your sunscreen has retinyl palmitate,
is it doing your skin more harm than good?
What is Retinyl Palmitate?
Both retinol and retinyl palmitate are widely used ingredients in skin care products. Both are forms of vitamin A. Retinol is a pure form of the vitamin found in green and yellow vegetables, egg yolks, whole milk, beef, chicken, and fish-liver oil. It's essential to vision and bone development and plays a role in vision health. Retinol is also hugely popular in skin care products because the skin naturally converts it to retinoic acid, which helps to stimulate collagen production, increase cellular rejuvenation, and decrease pore size, creating softer, smoother skin.
Retinyl palmitate is considered to be a gentler, milder form of vitamin A. A combination of retinol and palmitic acid, it has been found in studies to be an effective antioxidant. The skin must first convert it to retinol, then retinoic acid, for it to have the same anti-aging effects, so higher concentrations are used to stimulate skin repair.
What are the Concerns?
Retinyl palmitate is often used in sunscreen because of its antioxidant properties and gentle nature. It's gentle enough to be used on sensitive skin, yet theoretically adds antioxidant protection to help the skin ward off damage caused by UV rays.
The concern about retinyl palmitate in sunscreen (or in other products, really) came about when the EWG, a non-profit organization, highlighted a 2009 animal study by the National Toxicology Program (NTP). Researchers subjected hairless mice to simulated UV rays from lamps in the morning for five days a week, for 40 weeks. The mice received topical applications of either a control cream containing 0.001% retinoic acid or 0.1%, 0.5%, 1.0%, or 2.0% retinyl palmitate in the afternoon of the same days they were exposed to the light.
The conclusions: retinoic acid enhanced the photocarcinogenic activity of UVB rays in the mice and increased multiplicities of skin lesions. Retinyl palmitate also enhanced photocarcinogenicity, increased skin lesions, and increased the presence of squamous cell neoplasm's—the beginnings of skin cancer.
This study actually confirmed the results of other research. In 2006, for instance, scientists found in laboratory studies that when subjected to UVA light, retinyl palmitate acted as a “photosensitizer,” leading to free radical formation and the peroxidation of fatty cells.
Another study in 2005 found the same thing. Researchers wrote: “These results suggest that RP [retinyl palmitate] is photomutagenic in combination with UVA exposure in mouse lymphoma cells….” In other words, when retinyl palmitate was exposed to UV rays, it created changes in the skin that could lead to damage, aging, and cancer.
Because of these and other studies, the EWG issued a statement recommending that manufacturers of cosmetics, sunscreens, and other personal care products remove retinyl palmitate from all products to be used on sun-exposed skin, and that consumers avoid buying products that contain this chemical.
Some agencies disagree with the EWG's conclusions. In 2010, the American Academy of Dermatology defended the use of retinyl palmitate in sunscreen, stating there was “no convincing evidence” that the ingredient causes cancer. Their scientists assert that the ingredient acts differently in the real world, outside of the laboratory. In a commentary in the AAD journal, dermatologist Steven Wang stated:
“If studied on its own—outside of this environment [in combination with other antioxidants when applied to the skin], its antioxidant properties can rapidly be exhausted, allowing the production of oxygen radicals. In these non-human studies, retinyl palmitate was the only compound studied—making the biological relevance of these findings to humans unclear.”
AAD dermatologists also added that the mice used in the animal studies have a “marked propensity” to develop skin cancer because of their extra thin skin, and so the results should not be extrapolated to humans.
The Skin Cancer Foundation came up with similar conclusions, stating that the evidence did not support the claims that retinyl palmitate is a photocarcinogen.
Reviewing all this evidence is enough to make anyone confused. Should we worry about retinyl palmitate or not? Regardless of whether or not the ingredient is photocarcinogenic, we do know that if you're using vitamin A ingredients on your skin, you must avoid the sun. Look at any skin care product with retinol or retinyl palmitate or retinoic acid, and you'll see the warnings—use sunscreen, stay out of the sun, avoid sun exposure, etc. The warnings state that vitamin A products increase cell turnover and exfoliation, leaving skin more susceptible to damage from UV rays.
So regardless, vitamin A products make UV rays more dangerous to your skin. It seems to me that including them in sunscreens doesn't make a lot of sense? Dermatologists may argue that in combination with sunscreen ingredients and other antioxidants, they work well. I would not feel comfortable with that conclusion, particularly with what we know so far.
Why take the risk? There are plenty of sunscreens out there without vitamin A ingredients in them. I would suggest checking out the EWG's guide and using some of those safer options. Then, if you're using vitamin A in your skin care products, please go overboard in protecting yourself from the sun. The truth is, most people don't. They forget sunscreen, or forget to reapply. And we have no idea really, how effective those sunscreens are that we find in moisturizers or foundation products.
Do you avoid the use of retinyl palmitate? How about other vitamin A products?
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Photo courtesy tilak.dutta via Flickr.com.
Xia Q, et al., “Photoirradiatio of retinyl palmitate in ethanol with ultraviolet light—formation of photodecomposition products, reactive oxygen species, and lipid peroxides,” Int J Environ Res Public Health 2006 Jun;3(2):185-90.
Mei, N., et al., “Photomutagenicity of retinyl palmitate by ultraviolet a irradiation in mouse lymphoma cells,” Toxicol Sci. 2005 Nov;88(1):142-9, http://www.ncbi.nlm.nih.gov/pubmed/16107546.
Katie Bird, “Retinyl palmitate is safe for use in sunscreens, says AAD,” Cosmetic Design, August 10, 2010, http://www.cosmeticsdesign.com/Formulation-Science/Retinyl-palmitate-is-safe-for-use-in-sunscreens-says-AAD.