The Index · Organic UVA filter
Avobenzone
Butyl Methoxydibenzoylmethane
The main UVA1 organic filter in US sunscreens; photounstable unless paired with stabilisers.
StrongMultiple RCTs, consistent
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Avobenzone is the organic filter that gives most US chemical sunscreens their UVA coverage[1]. Its weakness is photostability: it degrades under UV, and in doing so can accelerate breakdown of octinoxate[2]. Modern formulas use octocrylene, bemotrizinol or encapsulation to stabilise it.
The US cap is 3 %; the EU allows 5 %[1]. In the US it cannot be formulated with zinc oxide or titanium dioxide, a monograph quirk rather than a chemistry problem.
Evidence by claim
Graded separately; the entry grade is the best-supported claim
Absorbs across UVA including UVA1[1]
StrongDegrades on UV exposure and can destabilise octinoxate unless stabilised[2]
StrongSafety & limits
Source and region, always
5 % · all — Annex VI entry 8: permitted to 5 %. EU UK
3 % · all — Sunscreen monograph: up to 3 %; FDA has requested more safety data on systemic absorption. US
5 % · all — Permitted to 5 %. CA AU
Sources · 2
Numbered as cited in the text
- [1]Sambandan DR, Ratner D. Sunscreens: an overview and update. Journal of the American Academy of Dermatology (2011)doi:10.1016/j.jaad.2010.01.005
- [2]Sayre RM, Dowdy JC, Gerwig AJ, et al.. Unexpected photolysis of the sunscreen octinoxate in the presence of the sunscreen avobenzone. Photochemistry and Photobiology (2005)doi:10.1562/2004-11-19-RA-378
Revision history
16 Sept 2026Entry createdTheSkindex Desk