Photoreaction, Phototoxicity, and Photocarcinogenicity of Retinoids

Abstract

Sunlight is a human carcinogen. Many retinoid-containing cosmetics are used to protect damages caused by sunlight irradiation. Since retinol is thermally unstable and retinyl palmitate (RP) is relatively more stable, RP is also widely used as an ingredient in cosmetic formulations. In general, little is known about the photodecomposition of retinoids and the toxicity of retinoids and their photodecomposition products on the skin's responses to sunlight. This review focuses on the update information on photoreactions, phototoxicity, and photocarcinogenicity of the natural retinoids including retinol, retinal, retinoid acid (RA), retinyl acetate, and RP.

^#This article is not an official guidance or policy statement of US Food and Drug Administration (FDA) or National Toxicology Program (NTP). No official support or endorsement by the US FDA and NTP is intended or should be inferred.

Keywords:

• Retinol
• Vitamin A
• Retinoid acid
• Retinyl palmitate
• Phototoxicity
• Photocarcinogenicity

Acknowledgments

We thank Dr. Frederick A. Beland for critical review of this manuscript. This research was supported in part by an Interagency Agreement #224-0001 between the Food and Drug Administration/National Center for Toxicological Research (FDA/NCTR) and the National Institute for Environmental Health Sciences/National Toxicology Program (NIEHS/NTP). Through this agreement, Q. Xia and S.-H. Cheng were supported by appointments to the Postgraduate Research Program at the NCTR administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the FDA.

Notes

^#This article is not an official guidance or policy statement of US Food and Drug Administration (FDA) or National Toxicology Program (NTP). No official support or endorsement by the US FDA and NTP is intended or should be inferred.