Lanolin (from latin lana “wool” and oleum “oil”) is the wax secreted by the sebaceous glands of wool-bearing animals, to protect the wool and skin from climate and the environment. Lanolin used by humans comes from domestic sheet breeds, raised for their wool. Lanolin is retrieved when freshly trimed sheep wool is washed.
Lanolin is not a pure molecule, but a complex mix of esters, fatty acids and high molecular alcohols. More 180 fatty acids and 80 alcohols were identified.
It is an amphiphilic ingredient (i.e. both lipophilic and hydrophilic), that forms very stable emulsions with water.
Lanolin has several functions in cosmetic products : antistatic, emollient, emulsifier, conditioner.
Lanolin is an extremely versatile ingredients, with many benefits for skin, hair, nails, lips. Some studies showed the similarity between human stratum corneum lipids and lanolin. Lanolin’s skin soothing action is very long lasting, forming semiocclusive (breathable) films on the skin. It would have superior barrier repair properties compared to petrolatum and glycerin.
Only issue with Lanolin, it cannot be used in vegan cosmetics, as being from animal origin.