FDA has been assessing the safety of alpha hydroxy acids (AHAs) in an effort to ensure that these products are safe for use by consumers. (For more background, see FDA's previous statement on AHAs.) Two FDA-sponsored clinical studies of AHAs have been completed as part of this effort. The agency will release the final reports in the near future.
These studies (1) compared the effect of AHAs on the sensitivity of human skin to ultraviolet (UV) radiation contained in sunlight with the effect of the same substance containing no AHAs, (2) measured how fast the skin returns to normal after use of the product is discontinued, and (3) investigated whether AHAs enhance UV-induced damage to DNA in the skin.
The studies clearly show a correlation between AHA use and a decrease in the time it takes for UV-induced redness to become visible on the skin (called the "minimum erythemal dose" or MED). In another measure of the effect of AHAs on the skin, the study found a correlation between the use of AHAs and an increase in the number of "sunburn" cells formed in the skin. Sunburn cells are skin cells that become damaged by UV light and, because of the damage, are eliminated from the body.
A study of the potential effects of AHAs on UV-induced DNA damage to skin cells failed to establish a conclusive link, although the data leave the question open and suggest a possible effect.
Finally, the studies demonstrated that, under the test conditions, the skin will return to normal within a week of discontinuing use of the product. This information is important in determining how best to protect oneself from the harmful effects of sunlight when using AHA products.
FDA provided the reports from these studies during a meeting of the Cosmetic Ingredient Review (CIR) on September 10, 1999 (1). The results, along with those of previous studies, help the agency to decide how best to protect the public health.
FDA is also collaborating with the National Toxicology Program to assess the safety of the long-term use of AHAs. The results of this investigation will not be available for several years. In the meantime, the agency will continue to work with the cosmetics industry to ensure that consumer health is protected.
For more information, see AHAs and UV Sensitivity: Results of New FDA-Sponsored Studies
See also: Suntan Products, Sunscreens, and Tanning, AHAs and BHAs
Hypertext updated by cjm/dms 2001-JUN-14