Lanolin is a greasy yellow substance made from secretions (sebum) from the skin glands of sheep to condition their wool. It is a natural, animal-derived product harvested from shorn wool. Unrefined lanolin has been used for thousands of years by various cultures, and refined lanolin has been used for more than a hundred of years in ointments. Lanolin is a long-chain waxy ester that contains cholesterol, but with a different composition than human sebum.

There are two common forms: lanolin and lanolin alcohol. The latter, the one that’s more commonly used in skin care, adds a molecule to provide a smoother skin feel. Because of its high fat content, lanolin is occlusive, meaning it prevents the evaporation of water from the skin (transepidermal water loss). This keeps skin moisturized and helps the skin heal.