Avobenzone vs Erythorbic 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 Erythorbic Acid?

Erythorbic acid is a stereoisomer of ascorbic acid (vitamin C) produced by fermentation of sucrose. While it has similar antioxidant properties to vitamin C, it has very little vitamin C activity (approximately 5%). It is primarily used in meat curing to accelerate the conversion of nitrite to nitric oxide, thereby speeding up the development of the characteristic pink color in cured meats.

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.

Erythorbic Acid: Erythorbic acid is generally recognized as safe. It is not carcinogenic, mutagenic, or teratogenic. At very high doses in animal studies, no toxicity was observed. It is metabolized similarly to ascorbic acid. When used alongside nitrites in cured meats, it serves the beneficial function of reducing nitrosamine formation, potentially making cured meats somewhat safer. No significant adverse effects have been documented at food use levels.