What is bemotrizinol, and why does the new sunscreen ingredient matter?

Shoppers can now buy sunscreens made with the first new active ingredient to reach the U.S. market in more than 25 years, a filter that guards against both major types of ultraviolet radiation without the chalky residue common to mineral products.

The Food and Drug Administration approved bemotrizinol, known as BEMT, on June 9. It was the first addition to the federal list of permitted over-the-counter sunscreen ingredients since the late 1990s. The Associated Press reported Wednesday that the first products containing it, including a Neutrogena formula, are reaching retailers.

HHS Secretary Robert F. Kennedy Jr. said at the time that the action would “increase competition and consumer confidence in sunscreen products.” The FDA considers the ingredient safe and effective for adults and for children 6 months and older, at concentrations up to 6%. The agency finalized the order within seven months of proposing it, using a streamlined process Congress created in 2020. DSM Nutritional Products, a Dutch manufacturer, requested the change.

The practical appeal is coverage. Sunscreens must block UVB rays, which cause most sunburn, and UVA rays, which carry the greatest risk of skin cancer and premature aging. Until now, chemical formulas had to combine several ingredients to do both. Mineral sunscreens made with zinc oxide or titanium dioxide cover both, but some users, particularly those with darker skin, avoid them because of white streaking or texture.

David Andrews of the Environmental Working Group, which advocates for tougher sunscreen standards, said the ingredient fills “a big gap” in strong UVA protection. Dermatologist Jennifer Stein of NYU Langone Health told the AP it is a good option for people who dislike how mineral products feel.

Safety data also favors BEMT, according to the AP. FDA reviewers found that studies of more than 500 patients showed nearly undetectable absorption into the skin. Daily use for up to three weeks caused no irritation or allergic reactions. Experts say it also holds up better in sunlight than avobenzone, the only other chemical UVA filter.

The AP also reported that the FDA revoked approval of the older ingredient oxybenzone last month, citing greater skin absorption than previously understood.

Environmental effects remain an open question. The European Union’s environmental agency has found limited evidence of toxicity to the environment from BEMT but says longer-term research is needed, the AP reported. Federal regulators do not classify sunscreens’ environmental impact, and labels such as “reef safe” have no standard definition.

Dr. Stein cautioned that sunscreen is only one layer of protection. Reapplying every few hours, seeking shade and wearing protective clothing all matter.