Retinyl palmitate in sunscreen
In the dermatology world, a controversy is brewing surrounding a possible link between the vitamin A derivative retinyl palmitate (RP) and an increase in skin cancer. In August 2010, an organization called the Environmental Working Group (EWG) reported the results of a study on mice that found that this common anti-aging ingredient speeds the growth of cancer cells when exposed to the sun. The EWG then recommended that all sunscreens containing RP be avoided. However, according to the FDA, they omitted one very significant fact: The mice used in this study were treated with an RP cream alone, not one with sunscreen. It is possible that the addition of a sunscreen ingredient could have altered this finding. (Check out this report that refutes the EWG claim.) This recent study aside, I’m not a big fan of RP anyway as an anti-aging ingredient. RP does provide some sun protection against UVB light but not against UVA light. There are plenty of other members of the vitamin A family that deliver better results.
What is the difference between retinol and retinyl palmitate?
Retinol and retinyl palmitate are members of the vitamin A family, which is also known as the "retinoid” family. The vitamin A family includes retinyl esters such as retinyl palmitate and retinyl linoleate; in addition to retinol, tretinoin, adapalene, tazorotene, oral Accutane and beta carotene. Since retinyl palmitate is a retinoid ester, this means it has a different chemical structure than retinol. In fact, once absorbed into the skin, RP is broken down into retinol. Because of the difference in chemical structure, each member of the retinoid family acts differently. The main thing that retinoids have in common is that they all act on retinoid receptors in the skin.
Retinol and tretinoin are better anti-aging ingredients than retinyl palmitate
All retinoids should be used at night because they break down when exposed to sunlight and lose their efficacy. Although they all bind to retinoid receptors, certain forms of retinoids absorb into skin better and therefore have a stronger action on the skin. Not all of the retinoids have been proven to improve skin aging. Tretinoin and retinol have been shown to improve aged skin when used topically. It does not make sense to add retinoids to a sunscreen formulation, in my opinion, because they lose their efficacy upon sun exposure. In addition, studies have shown that retinyl palmitate does not penetrate the skin well, and because it can remain on the skin surface, it can undergo changes when exposed to the sun. The main concern here is the production of free radicals, which can theoretically cause cellular damage that leads to skin cancer. It is this concern that has led to the EWG’s warnings.
Is vitamin A dangerous in sunscreen?
Retinyl palmitate (also known as retinyl ester) acts differently than other forms of retinol when exposed to UV light, so you can’t lump it together with all other vitamin A derivatives. My issue with the EWG report is that they use the term “vitamin A” when in fact the data refers to only one form of vitamin A—retinyl palmitate. I feel it is prudent to avoid RP in sunscreens but other forms of retinoids have not been shown to be harmful when used in the sun. In fact, many of these ingredients, especially beta carotene, have actually been shown to prevent cancer. However, I am sticking with the belief that in order to avoid the entire issue, retinoids should be used at night.
What retinoid products give the best anti-aging results?
I will admit I’m a bit concerned about these retinyl palmitate findings, but I feel that it is a moot point because I do not recommend RP-containing sunscreens anyway. With this chance of detrimental side effects and minimal benefits, there are much better options. To be on the safe side, I recommend retinoids be used only at night—and the best retinoids are retinol and tretinoin, which are proven to improve skin aging. I do not feel there is enough evidence to show that retinyl palmitate causes skin cancer, but I can’t find any good reasons to use it.
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