For your skin
The UVB workhorse behind most chemical sunscreens: effective, well-tolerated, and found in over 90% of chemical-filter formulas in the US. Important caveat: it covers UVB only, so it always needs a UVA partner (typically avobenzone). Also banned in Hawaii and reef-sensitive areas due to coral toxicity, so check the label if environmental impact matters to you.
Want the science? Keep reading ↓Mechanism of action
Octinoxate (ethylhexyl methoxycinnamate) is a cinnamate ester that absorbs UVB radiation (290–320 nm) with peak absorption at ~311 nm. It does not cover UVA wavelengths (320–400 nm) and must be combined with a UVA filter for broad-spectrum protection. The most frequently used UVB filter in US chemical sunscreen formulations; FDA-approved OTC drug active at up to 7.5%. Banned in Hawaii, Palau, and several other jurisdictions due to evidence of aquatic toxicity to coral reefs.
Why we tier this moderate
2 cited papers across 2 countries. The mechanism is well-described and there's at least one controlled trial in the literature, but we tier this Moderate rather than Strong to stay honest about how many specific papers we cite directly.
Cited research
Rai R, Shanmuga SC, Srinivas CR. Update on Photoprotection. Indian J Dermatol. 2012;57(5):335-42.
Golmohammadzadeh S et al., Evaluation of liposomal and conventional formulations of octyl methoxycinnamate on human percutaneous absorption using the stripping method, J Cosmet Sci 2008;59(5):385-98 — controlled comparison, liposomal octyl methoxycinnamate SPF efficacy
Sources: 10 clinical journals and regulatory databases across the US, EU, Korea, Japan, and China. Every entry points to a specific document. See methodology for the full list and what each outcome label means.