Avobenzone vs Zinc Oxide: 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 Zinc Oxide?

Zinc oxide is an inorganic mineral UV filter and skin protectant that provides broad-spectrum UVA and UVB protection by reflecting and scattering UV radiation. It is also an FDA-approved OTC active for diaper rash, minor skin irritation, and sunburn treatment.

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.

Zinc Oxide: Bulk zinc oxide used in traditional formulations has an excellent safety record. The primary concern is nanoparticle zinc oxide (nano-ZnO) used in transparent sunscreen formulations: the EU has reviewed nano-ZnO and found it safe for use in non-spray sunscreens (SCCS opinion 2022), but restricted it in spray products due to inhalation risk. Nano-ZnO does not penetrate intact skin. Zinc oxide is non-carcinogenic, non-hormone-disrupting, and reef-safer than chemical filters.