A long-used UVB filter, and part of the sunscreen that cut skin cancer in the landmark trial. Unstable next to avobenzone; banned in Hawaii over reef concerns.
Octinoxate is a cinnamate that absorbs UVB (peak around 310 nm). It has been one of the most widely used filters worldwide and is also added in small amounts to perfumes (where this catalogue lists it) and hair products to protect the product from light.
It degrades in sunlight, and it destabilises avobenzone when the two are combined without a stabiliser. Hawaii banned sunscreens containing it (and oxybenzone) from 2021 over coral-reef concerns.
The Nambour randomised trial sunscreen was 8% octinoxate + 2% avobenzone, and it reduced squamous-cell cancer and photoageing. Octinoxate is absorbed (around 5-8 ng/mL in the FDA trial) and is oestrogen-active in lab and high-dose rodent studies, but a human whole-body study at 10% found no hormone changes, and the EU's safety committee in 2025 concluded it is safe up to 10% given the large margin of safety. FDA lists it as needing more data.
In 903 adults under 55, daily broad-spectrum sunscreen for 4.5 years led to 24% less skin ageing (measured by skin-surface microtopography) than discretionary use; the daily group showed no detectable increase in ageing over the trial.
32 volunteers applied cream with 10% each of oxybenzone, octinoxate and 4-MBC over the whole body daily for a week. All three were absorbed (oxybenzone up to 200-300 ng/mL), but reproductive hormones showed no changes attributable to the filters.
Oxybenzone, homosalate, octinoxate and two other filters made breast-cancer cells proliferate in a dish; in immature rats, octinoxate and oxybenzone raised uterine weight only at very high oral doses (around 935 and 1,525 mg/kg/day). Avobenzone was inactive. Hazard screening, not evidence of effects at human exposure.
48 healthy adults applied one of four sunscreens to 75% of the body, up to 4 times a day for 4 days. Avobenzone, oxybenzone, octocrylene, homosalate, octisalate and octinoxate all exceeded the FDA's 0.5 ng/mL screening threshold after a single application; oxybenzone reached about 258 ng/mL from lotion. The authors state this does not mean people should stop using sunscreen.