Avobenzone vs Sodium Propionate: 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 Sodium Propionate?

Sodium propionate is the sodium salt of propionic acid. Like calcium propionate (E282), it is used as an antimicrobial preservative to prevent mold and bacterial spoilage in bread and baked goods. It is also used in poultry and animal feed applications.

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.

Sodium Propionate: The health profile is essentially the same as calcium propionate. The 2019 Science Translational Medicine study implicating propionate in metabolic changes applies to all propionate salts. Behavioral sensitivity concerns that have been anecdotally reported with calcium propionate may similarly apply. At regulated use levels, sodium propionate is considered safe by global regulatory agencies.