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Sunscreen filters

Octinoxate

Also listed as ethylhexyl methoxycinnamate, octyl methoxycinnamate, OMC, EHMC

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.

Strong evidenceTypical strength: Up to 7.5% (US), up to 10% (EU)

What it is

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.

How strong is the evidence?

Strong evidence

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.

What it's used for, checked

UVB protection

Holds up

Effective, but loses strength with sun exposure.

Hormone disruption in people

Unproven

Seen in cells and in rats at very high oral doses; a human study at 10% whole-body use found no attributable hormone change.

Harms coral reefs

Unproven

Mainly lab evidence at concentrations above most measured reef levels; bans are precautionary.

Don't combine with

  • avobenzone, unless the formula includes a stabiliser such as octocrylene or bemotrizinol

Who should be careful

  • Allergy is uncommon.
  • Sunscreens with it cannot be sold in Hawaii (and some other jurisdictions); check local rules when travelling.
  • Those limiting absorbed filters can choose mineral or newer large-molecule filters as a precaution.

The studies

Every citation is checked against its PubMed record.

  1. Sunscreen and prevention of skin aging: a randomized trial.
    Hughes MC, Williams GM, Baker P, Green AC · Ann Intern Med · 2013 · RCT

    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.

  2. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans.
    Janjua NR, Mogensen B, Andersson AM, et al. · J Invest Dermatol · 2004 · Controlled clinical 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.

  3. In vitro and in vivo estrogenicity of UV screens.
    Schlumpf M, Cotton B, Conscience M, et al. · Environ Health Perspect · 2001 · Laboratory and animal study

    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.

  4. Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial.
    Matta MK, Florian J, Zusterzeel R, et al. · JAMA · 2020 · RCT (pharmacokinetic)

    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.