Lanolin is a natural waxy substance originating from sheep’s wool. This secretion, also known as wool fat or wool grease, naturally protects and conditions the animal’s fleece. Its moisturizing and protective properties have led to its widespread use in various human applications, particularly in the cosmetic and pharmaceutical industries.
The Raw Material: Wool Grease
The journey of lanolin begins with wool grease, the raw, waxy substance found on sheep’s wool. This material is secreted by the sebaceous glands of domestic sheep, acting as a natural protective coating that waterproofs and moisturizes their wool and skin. Chemically, wool grease is classified as a wax, not a true fat, because it lacks glycerides. Instead, it is a complex mixture predominantly composed of long-chain waxy esters, making up approximately 97% of its weight, alongside smaller amounts of lanolin alcohols, acids, and hydrocarbons. This natural coating can constitute about 5% to 25% of the weight of freshly shorn wool, depending on factors like sheep breed and wool quality.
From Wool to Crude Lanolin: The Extraction Process
The initial separation of wool grease from shorn fleece occurs through scouring. This process involves washing raw wool in hot water with detergents to remove impurities like dirt, suint (sweat salts), and the wool grease. During washing, the wool grease forms a fine emulsion within the scouring liquid. To extract crude lanolin from this emulsion, the wash water is fed into high-speed centrifugal separators. Heavier impurities like sand are often removed by gravity settlement before centrifugation, and the centrifugal force then separates and concentrates the wool grease, yielding a dark, viscous substance known as crude lanolin.
Refining Lanolin: Purification and Grades
Once crude lanolin is extracted, it undergoes extensive refinement to remove impurities and enhance its quality, making it suitable for various applications. This multi-stage purification typically begins by breaking down soaps and removing acid-soluble contaminants, often involving treatment with aqueous acid solutions. The free fatty acids are then neutralized using alkaline treatments, such as sodium hydroxide. Subsequent steps include extracting resulting soaps with alcohol mixtures to eliminate undesired substances.
Additional purification involves treating lanolin with adsorbents, such as activated carbon, followed by filtration. Deodorization and pesticide residue removal are achieved by exposing lanolin to high vacuum and simultaneous heating, which also helps reduce free lanolin alcohols, contributing to hypoallergenic properties. Decolorization, or bleaching, often using agents like hydrogen peroxide, achieves a paler yellow or nearly white product, though color does not impact efficacy. The final step removes residual water through vacuum drying, which yields anhydrous lanolin.
The level of purification dictates the various grades of lanolin available.
Anhydrous lanolin is a water-free, highly concentrated form valued for its intense moisturizing capabilities.
Pharmaceutical grade lanolin (e.g., USP, BP, EP) meets stringent quality and safety standards, featuring ultra-purity and very low pesticide content, making it suitable for medical uses.
Cosmetic grade lanolin is processed for use in beauty products, while ultra-refined or hypoallergenic grades are highly purified to be nearly odorless and minimize allergic reactions.
Less refined technical grades are utilized in industrial applications, including rust-preventative coatings and lubricants.