Synthetic sunscreen ingredient (also known as Parsol 1789 and butyl methoxydibenzoylmethane) that can protect against the entire range of the sun’s UVA rays (Sources: Photodermatology, Photoimmunology, and Photomedicine
, August 2000, pages 147–155; and International Journal of Pharmaceutics
, June 2002, pages 85–94).
Avonenzone is sometimes cited as an endocrine-disrupting agent and this has some consumers concerned about using sunscreens with avobenzone. The facts: Ironically, the endocrine-disrupting potencies of sunscreen ingredients, including avobenzone, “are several orders of magnitude lower than that of the natural estrogens” (Source: Environment International, July 2007, pages 654–669). Other human endocrine-disrupting sources have a plant origin, such as marijuana (Source: Toxicology, January 2005, pages 471–488), or are found in medicines such as acetaminophen (Tylenol) (Source: Water Research, November 2008, pages 4578–4588). In the grand scheme of things, avobenzone’s endocrine-disrupting ability is inconsequential.
Research has also shown that avobenzone is safe for topical use and does not have a negative effect on skin cells. Some in vitro studies have indicated that there is a possibility that certain sunscreen ingredients can be absorbed into skin, and there are a handful of in vivo studies as well. However, there are still many researchers who believe that most sunscreen ingredients stay on the surface of skin (where skin cells are dead) and do not penetrate into the lower layers of skin where the real damage occurs. If that’s the case, it means the negative effects seen for surface skin in test tube studies may be irrelevant. Even when absorption has been shown, the related risk has not been demonstrated (Sources: American Journal of Clinical Nutrition, August 2008, pages 570S–577S; Environmental Health Perspectives, July 2008, pages 893–897; Journal of the American Academy of Dermatology, May 2008, pages S155–S159; Journal of the European Academy of Dermatology and Venereology, April 2008, pages 456–461; and Skin Pharmacology and Applied Physiology, July-August 2005, pages 170–174).
Lastly, you may have heard that avobenzone is unstable and shouldn’t be used in sunscreen products or that it cross-reacts with other sunscreen ingredients. The truth is that all sunscreen ingredients break down upon exposure to sunlight. That’s part of how they work to protect your skin and part of why reapplication during prolonged periods of sun exposure is necessary to maintain the level of protection the label states. Specific to avobenzone, it is not some untested, unproven sunscreen ingredient. It has been around since 1981 and is the most-used sunscreen ingredient in the world. It is the number-one sunscreen agent used in Canadian, Australian, and European sunscreen formulations. In the United States, the FDA approved avobenzone’s use as a sunscreen agent only after more than seven years of study. Avobenzone had to meet scrupulous performance standards when Hoffman LaRoche applied for it to receive new drug status from the FDA. New drug status is the most stringent FDA classification possible and requires more safety studies and efficacy substantiation than you can imagine. Avobenzone held up under all of the FDA’s safety and potency protocols, or it wouldn’t have been approved.