lanolin
Meaning of lanolin: Wax recovered from sheep wool and purified, valued because it holds water against the skin much as the skin's own oils do.
Definition of lanolin
Lanolin is a waxy substance produced by glands in sheep skin and recovered from shorn wool. Purified for use, it forms a soft, sticky ointment base that slows water loss from the skin and can hold a large amount of water mixed into it. It appears in moisturizers, lip and nipple preparations, and as the base of many ointments.
What does it do on the skin?
Two things at once. It forms a film that slows evaporation from the surface, which is what an occlusive does, and it softens the outer layer, which is what an emollient does. Its composition of waxy esters and alcohols resembles the natural oils human skin produces, so it spreads readily and is absorbed into the surface layers rather than sitting on top. It also holds roughly its own weight in water, which is why it works as the base of creams that need to carry water alongside oil.
Where is it used?
| Product | Purpose |
|---|---|
| Ointments for dry or cracked skin | A barrier that reduces water loss |
| Nipple preparations | Soreness during breastfeeding |
| Lip balms | Reduces chapping in wind and cold |
| Ointment bases | Carries other active ingredients into the skin |
| Industry | Rust prevention, leather and cosmetics |
Ointments combining several of these agents, such as a petrolatum, mineral oil, lanolin and ceresin ointment, use each for a different property. Lanolin is also the raw material from which vitamin D is manufactured, because the cholesterol it contains can be converted with ultraviolet light.
Can it cause a reaction?
It is a recognized contact allergen, although the rate is lower than its reputation suggests. The components usually responsible are the wool alcohols, and these are included in the standard series used for patch testing. Sensitization is far more likely on skin that is already damaged or inflamed, such as a leg ulcer or eczema, than on intact skin. Highly purified grades reduce but do not remove the risk, and a positive skin test to wool alcohols concerns the wax rather than wool fiber itself, so it has nothing to do with finding wool clothing itchy. Preparations labeled lanolin-free exist for people who have tested positive, and the substance is otherwise regarded as safe, including in products used on the nipple during breastfeeding.
Also known as
Used in a sentence
A lanolin-based ointment was applied to the cracked skin under an occlusive dressing.
Good to know
Lanolin allergy is tested with wool alcohols in the standard patch test series, and sensitization is much more common on broken or inflamed skin than on intact skin.
Word origin
Where “lanolin” comes from
From the Latin lana, meaning wool, and oleum, meaning oil.