Acetylated Lanolin Alcohol

Lanolin is the waxy stuff that sheep make to waterproof their wool, and Acetylated Lanolin Alcohol is one of its refine spin-offs.

It's basically the alcohol fraction of lanolin that gets reacted with acetic acid (the same acid in vinegar). This turns the stuff, sticky wax into a light, slippery oil.

In cosmetics, this ingredient is used as an emollient and occlusive that softens skin, spreads pigment nicely, and slows water loss.

The Cosmetic Ingredient Review panel has cleared it as safe up to 16% and you'll usually see it well under that in leave-on skincare.

There's no direct study on this ingredient for fungal acne, but you may want to avoid this ingredient if you have been diagnosed. This is because the Malassezia yeast can't build its own fatty acids and has to scavenge them from skin lipids. Lanolin-derived materials are long-chain esters that the yeast's lipases could in principle break down.

This ingredient has tested to be non-sensitizing in animal studies with only a low incidence of reactions across decades of widespread human use. People with already-compromised skin or lanolin allergies should patch-test because that's where the risk concentrates.

Is it comedogenic?

Old rabbit-ear testing scored it 4-5/5 for pore-clogging at full strength and at 50%, but only 1 once diluted to 2.5%.

Human testing later showed that finished products containing "comedogenic" ingredients aren't necessarily comedogenic themselves. Just remember that concentration and formulation matter far more than the ingredient's presence on the label.