Butyl Methoxydibenzoylmethane
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 the most widely used UVA sunscreen in the world and is permitted up to 5% in the EU and 3% in the US. A notable drawback is its photostability: it degrades upon sun exposure, losing approximately 36% of its UV-absorption capacity after one hour of sunlight. It is incompatible with mineral sunscreens (titanium dioxide and zinc oxide), a combination that is outright prohibited in the US.
Provides comprehensive UVA1 and UVA2 protection, making it the global gold standard for UVA defense. It shows no estrogenic effect and is considered non-irritating, giving it a favorable safety profile among chemical sunscreen agents. Photostability can be improved by combining it with stabilizing UV filters such as octocrylene, Tinosorb S, or Ensulizole, or through encapsulation.
Photounstable — degrades significantly after approximately one hour of sun exposure, necessitating regular reapplication. Combination with mineral sunscreens (titanium dioxide, zinc oxide) destabilizes avobenzone and is prohibited in the US. Maximum permitted concentration is 3% (US) and 5% (EU).
