Lanolin, derived from the Latin words for “wool” and “oil,” is a waxy substance secreted by the hair follicles of sheep, covering their fleece. Since sheep were first domesticated, this so-called “wool grease” has been harvested as an unavoidable by-product of processing wool into textile. A fortunate extract, lanolin has a variety of uses, including industrial water-repellent lubrication, but its widest application is in cosmetics and toiletries. Natural lanolin soap is a popular skin-cleansing bar for many people, especially discerning new mothers.
To create lanolin soap, the lanolin must first be extracted from the sheep. The lanolin can be pressed free from its coat, but most processors wash it off with warm, scouring detergent and then separate the liquefied, oil-like product with a spinning centrifuge. Repeated centrifugation, as well as removal of impurities such as sweat salts and organic pesticides used to maintain the healthy husbandry of herds, yields the increasingly higher grades of lanolin necessary to make lanolin soap.
When anhydrous, or purified to the extent of removing all trace of free water, lanolin is as hydrophobic or water-repellent as synthetic petrolatum, more commonly known under the brand name Vaseline®. Lanolin breathes; it is permeable to gases such as oxygen. Increasingly, laboratory studies support its hypoallergenic qualities of lanolin soap because of its resistance to chemical reactions with other human bodily compounds. Lanolin is a protective, anti-bacterial barrier for open skin wounds and a healing salve for skin disorders such as eczema.
There are several other properties of lanolin which make it ideal for lotions, creams, soaps and other cosmetic products. It is a lubricant, a purely physical aid against abrasion. It readily emulsifies, or breaks apart and suspends evenly throughout a liquid medium. It melts and spreads at just above body temperature — about 100 degrees Fahrenheit (38 Celsius).
Lanolin soap takes advantage of its defining emollient function. It water-proofs a sheep’s fur coat and skin; and conversely, prevents the loss of moisture within skin to evaporation. Likewise for human skin, it is a protective barrier for maintaining hydration balance while retaining skin’s other natural functions. Not that a smooth baby’s bottom needs it, lanolin soap is a gentle skin cleanser favored by some new mothers.