Avobenzone vs Lactic Acid: which is worse?

What is Avobenzone?

Avobenzone (INCI: Butyl Methoxydibenzoylmethane) is a chemical UV filter that is the only FDA-approved broad-spectrum UVA-absorbing active sunscreen ingredient in the US that covers the full UVA spectrum (320–400 nm). It is inherently photounstable and must be combined with photostabilizers.

What is Lactic Acid?

Lactic acid is an organic acid naturally produced during fermentation of carbohydrates by lactic acid bacteria. It gives fermented foods such as yogurt, cheese, and sauerkraut their characteristic tangy flavor. Commercial lactic acid used in food is produced by bacterial fermentation of glucose or lactose, or in some cases by chemical synthesis.

Documented risks

Avobenzone: Avobenzone is effective and considered safe at approved concentrations (up to 3% in US OTC sunscreens). A 2019 FDA study found that several sunscreen actives including avobenzone were systemically absorbed above the 0.5 ng/mL threshold after repeated use, triggering a call for additional safety data. This does not indicate harm, but the FDA requested more studies under its proposed sunscreen monograph. Current evidence supports its continued safe use. No clear endocrine disruption or carcinogenicity at human exposure levels is established.

Lactic Acid: Lactic acid is a normal byproduct of human metabolism (produced during anaerobic exercise). It is generally recognized as safe at food additive levels. Excessive consumption of foods acidified with lactic acid could theoretically contribute to dental erosion, as with all acidulants. For individuals with rare inborn errors of lactate metabolism, dietary lactic acid may require monitoring.