Avobenzone (2.80%)
Butyl Methoxydibenzoylmethane, commonly known as Avobenzone, is a chemical UV filter and the only globally available sunscreen agent providing broad UVA protection across the full UVA range (310–400 nm), with peak absorption at 360 nm. It is used at a maximum concentration of 3% in the US and 5% in the EU. A key limitation is its photostability: it degrades upon sun exposure, losing approximately 36% of its UV-absorption capacity after one hour of sunlight. It is often combined with stabilizing agents such as octocrylene, Tinosorb S, or Ensulizole to address this issue.
Avobenzone provides comprehensive UVA1 and UVA2 protection, making it the global gold standard for UVA defense in sunscreen formulations. It has a favorable safety profile, is considered non-irritating, and shows no estrogenic effect unlike some other chemical sunscreen agents.
Photounstable — degrades significantly after one hour of sun exposure; must be reapplied regularly. Combination with mineral sunscreens (titanium dioxide, zinc oxide) destabilizes avobenzone and is prohibited in the US. Stabilizing co-filters (e.g., octocrylene, Tinosorb S, Ensulizole) are recommended but do not fully resolve photodegradation.
