Absorbs UVA (310–400 nm) via keto-enol tautomerisation. Photo-unstable alone — degrades ~40% in 1 hour of sun exposure. Stabilised by combination with octocrylene / Mexoryl / Tinosorb. Minimal systemic absorption (FDA 2019 study detected plasma levels but clinical significance unclear).
Target Organ Systems
integumentary
Interactions
Octinoxate (caution): Octinoxate destabilises avobenzone on photoexposure — combinations need additional photo-stabilisers.