Lanolin is a natural wax derived from sheep’s wool, often recognized as a moisturizing ingredient. Chemically, it is classified as a wax composed primarily of complex esters, lacking the glycerides found in true fats. The substance functions as an effective emollient and protective barrier, making it highly valued in various commercial products. Transforming this raw material into a purified, usable product requires a series of manufacturing steps.
The Natural Origin of Wool Grease
Lanolin begins as a waxy secretion from the sebaceous glands of wool-bearing animals, primarily domestic sheep. This raw, unrefined form is referred to as wool grease. Its biological purpose is to provide a natural weatherproofing layer for the sheep’s fleece and skin. Its hydrophobic properties allow it to repel water, helping the animal shed rain and protecting the wool fiber.
Wool grease is a complex mixture, predominantly consisting of long-chain waxy esters. The remainder is composed of lanolin alcohols, lanolin acids, and hydrocarbons. Depending on factors like the sheep’s breed and diet, the grease can constitute between 5% and 25% of the weight of the freshly shorn wool.
Initial Extraction of Crude Lanolin
Harvesting lanolin begins immediately after the sheep are shorn. The first major step is “scouring,” a deep-cleaning wash of the raw wool. The wool is run through wash bowls containing hot water and a mild detergent, which removes dirt, debris, wool grease, and suint (sweat salts). The resulting mixture of water, detergent, and suspended lanolin is known as scour liquor.
Heavy impurities like sand and dirt are often removed from the liquor through gravity settlement before separation. The crude lanolin wax is then separated from the aqueous scour liquor using high-speed centrifugation. This process concentrates the low-density wool grease into a waxy, semi-solid substance. This initial product, known as crude lanolin, is highly impure, appearing dark and sticky with a strong odor, and containing residual water and detergents.
Refining Lanolin for Commercial Use
Crude lanolin must undergo extensive refinement to become the pale, odorless substance required for commercial products. This multi-stage process removes remaining impurities and standardizes the wax’s composition. One of the first steps involves neutralizing the free fatty acids present in the crude material through an alkaline treatment. The resulting soaps are then extracted using a mixture of water and alcohol to wash away these undesired substances, improving stability and reducing potential irritation.
Further purification often involves treating the wax with adsorbents like activated clay to remove color and odor compounds. For high-grade products, the lanolin undergoes bleaching to achieve a pale yellow or near-white color, typically using oxidizing agents. To ensure the highest purity, especially for pharmaceutical applications, the lanolin may be subjected to high-temperature vacuum treatment or steam stripping. This step is effective at eliminating residual pesticides, detergents, and volatile odorous compounds.
Primary Commercial Applications
Once fully refined, lanolin is designated as anhydrous lanolin, meaning it is virtually water-free and ready for commercial use. In the pharmaceutical and personal care sectors, its occlusive and emollient properties make it a staple ingredient. It is frequently used as a hydrophobic carrier in water-in-oil creams and ointments due to its ability to absorb up to twice its weight in water without separating.
Lanolin that meets strict guidelines, such as those from the United States Pharmacopeia (USP), is used in sensitive topical applications, including medicated ointments and baby care products. Beyond personal care, lanolin is valued in industrial applications for its lubricating and anti-corrosive characteristics. It is used in rust-preventative coatings, specialized low-temperature lubricants, and as an additive in cutting emulsion oils.