Less known facts about: Lanolin

This article is part of the “Less Known Facts About Excipients” series by Philippe Tschopp.

Lanolin Excipient: Origin, Chemistry, and Pharmacopoeial Grades

Lanolin is a wax secreted by the sebaceous glands of sheep, not an extract of the wool fiber itself. It is recovered from raw wool during scouring, then refined until it meets compendial specifications, and it works in topical formulations as an emollient and a water-in-oil emulsifying excipient [7,8].

Where lanolin actually comes from

Lanolin is one of the oldest pharmaceutical excipients still in widespread use today, and despite that history its origin and unique chemistry are often overlooked [8]. It is not extracted from the wool fibers themselves. It is a natural wax secreted by the sebaceous glands of sheep, where it protects the skin and fleece against moisture and environmental exposure [8]. After shearing, the wax is recovered from the raw wool during the scouring process and subsequently refined to pharmaceutical quality [8].

The compendia describe the same material in procedural terms. USP-NF defines lanolin as “the purified, wax-like substance from the wool of sheep, Ovis aries L. (Fam. Bovidae), that has been cleaned, decolorized, and deodorized” [1].

How pharmaceutical lanolin is produced

The production process consists of four main steps [8]:

• Raw wool contains wool fibers, wool grease (lanolin), suint (perspiration salts), and environmental contaminants.
• The wool is washed with warm water and detergents. The wool grease separates from the fibers and is collected from the wash liquor.
• Centrifugation and purification steps recover the crude lanolin from the aqueous phase.
• Pharmaceutical-grade lanolin undergoes multiple purification steps to remove water, free fatty acids, pigments, odors, pesticide residues, and other impurities until it complies with pharmacopoeial specifications.

What compliance means is set out in numbers. USP-NF lanolin contains not more than 0.25% water and not more than 0.02% of a suitable antioxidant [1]. A separate USP-NF monograph covers modified lanolin, which has been processed to reduce the contents of free lanolin alcohols and residues of detergent and pesticide, and which limits pesticide residues to not more than 1 ppm for any individual specified residue and not more than 3 ppm in total [2]. Grade selection in practice is covered in the portal’s lanolin manufacturing FAQ.

What makes lanolin chemically unusual

Chemically, lanolin is one of the most complex natural waxes known. Rather than being a single substance, it consists of thousands of different esters, together with sterols, sterol esters, fatty alcohols, and long-chain fatty acids [8]. This complex composition gives lanolin several remarkable properties, including the ability to absorb significant quantities of water while maintaining its semi-solid, lipophilic character. As a result it functions as an emollient and a water-in-oil emulsifying excipient [8].

The sterol fraction carries much of that character. In the Cosmetic Ingredient Review Expert Panel’s assessment, 68% of lanolin alcohols are sterols, divided into 42% dimethyl sterols (cholesterols) and 26% pentamethyl sterols (lanosterols), the latter also described as triterpene alcohols [3].

Where it is used in formulation

Pharmaceutical-grade lanolin is used in numerous topical formulations, including ointments, creams, dermatological preparations, wound care products, nipple creams, ophthalmic preparations (in highly purified grades), and transdermal formulations [8]. Its primary functions include improving skin hydration, reducing transepidermal water loss, enhancing spreadability, providing consistency to semi-solid formulations, and supporting water-in-oil emulsions [8]. Related formulation work appears in ointment formulations and semi-solid transdermal dosage forms.

Nipple preparations show how far purification can be taken. The LactMed record notes that lanolin has traditionally been used topically to treat sore, cracked nipples during breastfeeding, and that highly purified products have the pesticide and detergent residues removed and their natural free alcohols reduced to below 1.5% to improve safety and reduce the allergic potential [4].

Considerations for formulators

As an animal-derived excipient, lanolin requires extensive purification and quality control. Modern pharmacopoeial grades are highly refined and tested for identity, purity, and residual contaminants. Formulators may nevertheless prefer synthetic or plant-derived alternatives for vegan products, for certain regulatory strategies, or for patients with known lanolin hypersensitivity [8].

That last consideration has a substantial evidence base behind it. The American Contact Dermatitis Society named lanolin its Allergen of the Year for 2023, identifying the responsible components as mainly the free lanolin alcohols, especially alkanediols, and reporting a prevalence of lanolin contact allergy in dermatitis patients ranging from 1.2% to 6.9% [5]. The same review describes lanolin as a rare sensitizer in patients with healthy skin, with allergic contact dermatitis appearing most often in those who have stasis dermatitis, chronic leg ulcers, atopic dermatitis, or perianal and genital dermatitis [5]. A patch-test series covering 30,629 patients in northeastern Italy between 1997 and 2021 returned a lanolin positivity rate of 1.64% [6]. Even highly purified lanolin should be avoided in patients with a known allergy to wool [4].

By Philippe Tschopp
Philippe Tschopp writes about pharmaceutical excipients, formulation and oral drug delivery, with a focus on excipient functionality, practical formulation considerations and lesser-known material properties.

Sources

1. United States Pharmacopeia-National Formulary (USP-NF). Monograph: Lanolin. https://doi.usp.org/USPNF/USPNF_M44300_01_01.html
2. United States Pharmacopeia-National Formulary (USP-NF). Monograph: Modified Lanolin. https://doi.usp.org/USPNF/USPNF_M44310_01_01.html
3. Cosmetic Ingredient Review Expert Panel. Amended Safety Assessment of Lanolin and Lanolin-Derived Ingredients as Used in Cosmetics, 2024. https://www.cir-safety.org/sites/default/files/FAR_Lanolin_092024.pdf
4. Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development. Lanolin. Revised January 15, 2025. https://www.ncbi.nlm.nih.gov/books/NBK501842/
5. Lanolin: The 2023 American Contact Dermatitis Society Allergen of the Year. Cutis, 2023. https://cdn.mdedge.com/files/s3fs-public/CT112002078.pdf
6. Sensitization to Lanolin in North-Eastern Italy, 1997-2021: Prevalence, Risk Factors and the Impact of Occupation. https://pmc.ncbi.nlm.nih.gov/articles/PMC11355248/
7. Rowe RC, Sheskey PJ, Quinn ME (Eds.). Handbook of Pharmaceutical Excipients. Pharmaceutical Press / American Pharmacists Association.
8. Source newsletter: Philippe Tschopp, “Less Known Facts About Excipients #1: Lanolin,” LinkedIn newsletter, August 5, 2026. https://www.linkedin.com/pulse/less-known-facts-excipients-1-lanolin-philippe-tschopp-bumze/

Disclaimer

This article is based on publicly available information and industry sources at the time of writing and supported by AI. While every effort has been made to ensure accuracy, completeness, and fair representation, the author does not guarantee that all information is current, error-free, or reflective of the latest developments.

This article is for informational purposes for pharmaceutical industry professionals and does not constitute regulatory advice. Always refer to the current pharmacopoeial monograph, the supplier’s current technical data sheet, and applicable regulatory guidance for your dosage form, route of administration, and market. Pharma Excipients International AG is not a manufacturer of the excipients discussed.

Read also the other article from the series “Less known facts about…” here:

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• Pullulan- coming soon
• Carnauba Wax- coming soon
• Gum Arabic- coming soon