Octocrylene

Octocrylene is an oil-soluble organic UV filter that mainly absorbs UVB and short wave UVA II light.

Its real superpower is teamwork: octocrylene is remarkably photostable and is most famous for stabilizing avobenzone (the workhorse UVA filter).

This ingredient is commonly used to enhance both UVB and UVA protection due to its unique property in stabilizing avobenzone. It also pulls double duty by boosting water resistance and giving formulas a smooth, spreadable feel.

The EU's Scientific Committee on Consumer Safety (SCCS) has deemed octocrylene to be safe as a UV-filter at concentrations up to 10% (capped at 9% in propellant sprays). The US also permits it up to 10%.

Two things worth knowing:

1. It's a fairly rare contact allergen but people who have had a photoallergy to the topical painkiller ketoprofen can cross-react with it.
2. Over time, a small amount of Octocrylene can break down into a substance called Benzophenone, which is why brands monitor it and keep levels in check.

You'll usually see this ingredient used in concentrations between 2-10% (higher amounts when used as a stabilizer for avobenzone).