Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate

MCE is a synthetic chemical sunscreen filter that L'Oreal and BASF developed to cover "ultra-long" UVA-I rays in the 370-400nm range.

Older UVA filters taper off around 370m, leaving the deep-penetrating wavelengths uncovered. These wavelengths are heavily linked to pigmentation, dark spots, and photoaging.

The evidence behind it is solid for a newer filter: adding MCE extended a sunscreen's absorption all the way to 400 nm, reduced UVA-I damage at the cellular + molecular level, and decreased UVA-I trigger pigmentation in a randomized controlled trial plus 3D-skin-model work. The 1.5% version also outperformed a reference sunscreen.

Later, a set of three randomized controlled trials under both lab and real-sun conditions backed up the added real-world protection.

The EU's Scientific Committee on Consumer Safety has concluded MCE is safe as a UV filter up to a maximum of 3% except in sprayable products. This isn't because MCE is dangerous, but because lung exposure hasn't been assessed yet.

You'll also find this ingredient in South Korea and Australia, but it hasn't been approved in the US or Canada yet.

Most formulas typically use somewhere in the ~0.7-1.5% range.

While MCE is generally well-tolerated, there's a single published case of allergic contact dermatitis to it.