Lanolin

Lanolin is a waxy substance secreted by the sebaceous glands of wool-bearing sheep. It is an effective moisturizer that works as both a humectant and emollient.

As a humectant, it is able to absorb up to 400% of its own weight in water; this also gives it emulsifying properties as it can help stabilize water-in-oil emulsions.

On the other hand, lanolin is able to reduce transepidermal water loss (TEWL) by about 20-30%. It can also incorporate into the lipid matrix to surround skin cells and reinforce the skin barrier.

This is why you'll see lanolin as an ingredient for heavy-duty moisturizers.

You might have seen an "allergy concern" that gives lanolin a bad reputation. The rate of lanolin contact allergy in the general population is estimated to be under 0.5%, and most of these are seen in people with compromised-skin dealing with eczema, atopic dermatitis, or leg ulcers.

Healthy, intact skin tolerates lanolin well. Even people who have previously reacted to it test negative on patch tests when the test is done on normal skin.

Is Lanolin vegan?

Because lanolin comes from an animal, it is not considered vegan. Sheep secrete lanolin through sebaceous glands to help protect their skin from the environment.

Pore clogging

Lanolin has a reputation as pore clogging but that comes almost entirely from rabbit ear testing done decades ago (and that model has aged badly).

This ingredient does have a comedogenic rating of 0-1; the tests state this score means the ingredient has low or non-existent chance of clogging your pores.

Keep in mind that the authors of the rabbit ear test proposed that a material needs to score consistently above 3 in the rabbit assay before it means anything for real skin.

A separate review found the model has serious performance problems and no correlation with human experience. Concentration matters a lot too: in one study, Acetylated Lanolin Alcohol scored 4 to 5 at full strength but dropped to a 1 when diluted to 2.5%, and finished products containing "comedogenic" ingredients didn't raise microcomedone counts in people.

Fungal acne

Lanolin contains esters exactly in the range that the Malassezia yeast can synthesize, making this ingredient not fungal acne safe.