Editing Lanolin

{{short description|Yellow waxy substance secreted by the sebaceous glands of wool-bearing animals}}
{{About|the sheep grease|the fictional characters|U.S. Acres#Lanolin Sheep{{!}}''U.S. Acres'' § Lanolin Sheep|and|Sonic the Hedgehog (IDW Publishing){{!}}''Sonic the Hedgehog'' (IDW Publishing)}}
[[File:AdepsLanaeCrudus-Lanolin.JPG|thumb|Wool fat tin (adeps lanae), at the ''Centre touristique de la Laine et de la Mode'' in Verviers, Belgium]]

'''Lanolin''' (from [[Latin]] {{wikt-lang|la|lāna}} 'wool', and {{wikt-lang|la|oleum}} 'oil'), also called '''wool fat''', '''wool yolk''', '''wool wax''', '''sheep grease''', '''sheep yolk''', or '''wool grease''', is a wax secreted by the [[sebaceous gland]]s of [[wool]]-bearing animals.<ref>{{Cite journal |last=Malmstrom |first=Ivar |year=1949 |title=Technological aspects of lanolin |url=https://library.scconline.org/v001n04/27 |journal=Journal of Cosmetic Science |volume=1 |issue=4 |access-date=4 November 2021 |archive-date=4 November 2021 |archive-url=https://web.archive.org/web/20211104024404/https://library.scconline.org/v001n04/27|url-status=live}}</ref> Lanolin used by humans comes from [[domestic sheep]] [[Domestic sheep#Breeds|breeds]] that are raised specifically for their wool. Historically, many [[pharmacopoeia]]s have referred to lanolin as wool fat (''[[wikt:adeps#Latin|adeps]] lanae''); however, as lanolin lacks [[glycerides]] (glycerol esters), it is not a true fat.<ref name=lanolin_book>{{cite book |title=The Lanolin Book |editor-first=Udo |editor-last=Hoppe |publisher=Beiersdorf |location=Hamburg |date=1999 |isbn=9783931146054}}</ref><ref name="barnett">{{cite journal |last=Barnett |first=G. |title=Lanolin and Derivatives |journal=Cosmetics & Toiletries |issn=0361-4387 |volume=101 |pages=21–44 |year=1986 }}</ref> Lanolin primarily consists of [[sterol]] esters instead.<ref>{{Ullmann |doi = 10.1002/14356007.a09_565.pub2| title = Esters, Organic |last1=Riemenschneider |first1 = W. |last2 = Bolt |first2 = H. M.}}</ref> Lanolin's [[waterproofing]] property aids sheep in shedding water from their coats. Certain breeds of sheep produce large amounts of lanolin.

Lanolin's role in nature is to protect wool and skin from climate and the environment; it also plays a role in skin ([[Integumentary system|integumental]]) hygiene.<ref name=lanolin_book/> Lanolin and its derivatives are used in the protection, treatment, and beautification of human skin.<ref name=lanolin_book/>

== Composition ==

A typical high-purity grade of lanolin is composed predominantly of [[long chain]] waxy [[ester]]s (approximately 97% by weight) with the remainder being lanolin [[Alcohol (chemistry)|alcohol]]s, lanolin [[acid]]s and lanolin [[hydrocarbon]]s.<ref name=lanolin_book/>

An estimated 8,000 to 20,000 different types of lanolin esters are present in lanolin, resulting from combinations between the 200 or so different lanolin acids and the 100 or so different lanolin alcohols identified so far.<ref name=lanolin_book/><ref name=barnett/>

Lanolin’s complex composition of long-chain esters, hydroxyesters, diesters, lanolin alcohols, and lanolin acids means in addition to its being a valuable product in its own right, it is also the starting point for the production of a whole spectrum of lanolin derivatives, which possess wide-ranging chemical and physical properties. The main [[derivatisation]] routes include [[hydrolysis]], fractional solvent [[crystallisation]], [[esterification]], [[hydrogenation]], [[alkoxylation]] and [[Menshutkin reaction|quaternisation]].<ref name=lanolin_book/><ref name=barnett/><ref>{{cite web|url=http://mw4.m-w.com/medical/quaternizing?show=0&t=1306177224|website=Merriam-Webster Medical Dictionary|title=Quaternise|quote=quaternise: to convert (as an amine) into a quaternary compound|access-date=23 May 2011|archive-url=https://web.archive.org/web/20120315184040/http://mw4.m-w.com/medical/quaternizing?show=0&t=1306177224|archive-date=15 March 2012|url-status=dead}}</ref><ref>{{cite web|url=http://www2.basf.us/businessdevelopment/bcbdevalkoxylation.html|title=Alkoxylation|publisher=BASF|quote=Reaction of ammonia or amines with [[ethylene oxide]] or [[propylene oxide]] to produce aminoalcohols. The process is also adaptable to produce specialty aminoalcohols from other epoxides.|access-date=23 May 2011|archive-date=16 January 2021|archive-url=https://web.archive.org/web/20210116214322/http://www2.basf.us/businessdevelopment/bcbdevalkoxylation.html|url-status=live}}</ref> Lanolin derivatives obtained from these processes are used widely in both high-value [[Cosmetics|cosmetic]]s and [[Dermatology|skin treatment]] products.

[[Hydrolysis]] of lanolin yields lanolin alcohols and lanolin acids. Lanolin alcohols are a rich source of [[cholesterol]] (an important skin lipid) and are powerful water-in-oil [[emulsifier]]s; they have been used extensively in skincare products for over 100 years.<ref name=lanolin_book/> Approximately 40% of the acids derived from lanolin are [[alpha-hydroxy acid]]s (AHAs).<ref name=lanolin_book/><ref name=barnett/> The use of AHAs in skin care products has attracted a great deal of attention in recent years.{{citation needed|date = September 2023}} Details of the AHAs isolated from lanolin can be seen in the table below.

{| class="wikitable"
|-
! Type of lanolic acid
! Carbon chain length
! Number identified
|-
| Alpha-hydroxy normal 
| {{chem|C|13|–C|24}}
| 12
|-
| Alpha-hydroxy iso
| {{chem|C|13|–C|23}}
| 6
|-
| Alpha-hydroxy anteiso
| {{chem|C|12|–C|24}}
| 7
|}

== Production ==

Crude lanolin constitutes about 5–25% of the weight of freshly shorn wool. The wool from one [[Merino sheep]] will produce about 250–300&nbsp;ml of recoverable wool grease. Lanolin is extracted by washing the wool in hot water with a special wool scouring detergent to remove dirt, wool grease (crude lanolin), [[suint]] (sweat salts), and anything else stuck to the wool. The wool grease is continuously removed during this washing process by [[Centrifugation|centrifuge]] separators, which concentrate it into a waxlike substance melting at approximately {{convert|38|°C}}.<ref>{{Cite journal|last1=Sengupta|first1=Amit|last2=Behera|date=2014|title=Comprehensive view on chemistry, manufacturing & applications of lanolin extracted from wool pretreatment,also used in vitamins|url=http://ajer.org/papers/v3(7)/F0373343.pdf|journal=American Journal of Engineering Research|volume=3|issue=7|pages=33–43|access-date=13 November 2018|archive-date=13 July 2019|archive-url=https://web.archive.org/web/20190713075638/http://ajer.org/papers/v3(7)/F0373343.pdf|url-status=live}}</ref>

== Applications ==
[[file:Lanolinezalf - detail.jpg|thumb|Lanolin ointment]]

Lanolin and its many derivatives are used extensively in both the personal care (e.g., high value cosmetics, facial cosmetics, lip products) and health care sectors such as topical liniments. Lanolin is also found in lubricants, rust-preventive coatings, shoe polish, and other commercial products.<ref name="Zirwas 2008">{{cite journal|pmid=21212847|pmc=3016930|year=2008|last1=Zirwas|first1=M. J.|title=Moisturizer allergy: Diagnosis and management|journal=Journal of Clinical and Aesthetic Dermatology|volume=1|issue=4|pages=38–44|last2=Stechschulte|first2=S. A.}}</ref>

Lanolin is a relatively common allergen and is often misunderstood as a wool allergy. However, allergy to a lanolin-containing product is difficult to pinpoint and often other products containing lanolin may be fine for use. Patch testing can be done if a lanolin allergy is suspected.<ref name="Zirwas 2008"/>

It is frequently used in protective baby skin treatment and for sore nipples from breastfeeding<ref>{{cite web |url=https://www.lansinoh.com/products/hpa-lanolin |title=HPA® Lanolin Cream |website=lansinoh.com |access-date=1 December 2014 |archive-url=https://web.archive.org/web/20150404194921/https://www.lansinoh.com/products/hpa-lanolin |archive-date=4 April 2015 |url-status=dead }}</ref> but health authorities recommend alternative methods first, including nipple cleaning<ref>{{Cite web |last=Agence Nationale d'Accréditation et d'Évaluation en Santé (French Health Authority) |date=May 2022 |title=Allaitement maternel - Recommandations (Maternal breastfeeding - advice) |url=https://www.has-sante.fr/upload/docs/application/pdf/Allaitement_recos.pdf |access-date=May 24, 2023 |website=Haute Autorité de Santé}}</ref> and improving baby positioning as well as expressing milk by hand. Lanolin is reported to have soothing properties but the lack of research leads to the previous recommendations being primary.<ref>{{Cite web |last=National Health Service (UK) |title=Sore or cracked nipples when breastfeeding |date=7 December 2020 |url=https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/breastfeeding-problems/sore-nipples/ |access-date=May 24, 2023}}</ref>

Lanolin is used commercially in many industrial products ranging from [[rust]]proof coatings to [[lubricant]]s. Some sailors use lanolin to create slippery surfaces on their [[propeller]]s and stern gear to which [[barnacles]] cannot adhere. Commercial products (e.g. Lanocote) containing up to 85% lanolin<ref>{{cite web |url=http://www.jamestowndistributors.com/userportal/pdfs/MSDS/LanoCote/b65f457msds.pdf |title=MSDS for Lanocote |website=www.forespar.com/products/boat-lubricant-lanocote.shtml |access-date=17 May 2018 |archive-date=18 May 2018 |archive-url=https://web.archive.org/web/20180518055823/http://www.jamestowndistributors.com/userportal/pdfs/MSDS/LanoCote/b65f457msds.pdf |url-status=live }}</ref> are used to prevent corrosion in marine fasteners, especially when two different metals are in contact with each other and saltwater. The [[water-repellent]] properties make it valuable in many applications as a lubricant grease where [[corrosion]] would otherwise be a problem.

[[7-Dehydrocholesterol]] from lanolin is used as a raw material for producing [[cholecalciferol|vitamin D<sub>3</sub>]] by irradiation with ultraviolet light.<ref>{{Cite journal | pmid = 17634462| year = 2007| last1 = Holick| first1 = M. F| title = Vitamin D deficiency| journal = New England Journal of Medicine| volume = 357| issue = 3| pages = 266–81| doi = 10.1056/NEJMra070553| s2cid = 18566028}}</ref>

[[Baseball player]]s often use it to soften and break in their [[baseball glove]]s ([[shaving cream]] with lanolin is popularly used for this).

Anhydrous liquid lanolin, combined with [[paraben]]s, has been used in trials as [[artificial tears]] to treat [[keratoconjunctivitis sicca|dry eye]].<ref name="Wang">{{cite journal |last1=Wang |first1=I. J. |last2=Lin |first2=I. C. |last3=Hou |first3=Y. C. |last4=Hu |first4=F. R. |title= A comparison of the effect of carbomer-, cellulose- and mineral oil-based artificial tear formulations |journal=European Journal of Ophthalmology|volume=17 |issue=2|pages= 151–159 |date=2007 |doi=10.1177/112067210701700202 |pmid= 17415686|s2cid=36508740 }}</ref><ref name="Pucker">{{cite journal |last1=Pucker |first1=A. D. |last2=Ng |first2=S. M. |last3=Nichols |first3=J. J. |title= Over the counter (OTC) artificial tear drops for dry eye syndrome |journal=Cochrane Database of Systematic Reviews|volume=2016 |pages= CD009729 |date=2016 |issue=2 |pmid= 26905373 |pmc= 5045033 |doi= 10.1002/14651858.CD009729.pub2}}</ref> Anhydrous lanolin is also used as a lubricant for [[brass instrument]] tuning slides.

Lanolin can also be restored to [[wool]]len garments to make them water and dirt repellent, such as for [[cloth diaper]] covers.

Lanolin is also used in [[lip balm]] products such as [[Carmex]]. For some people, it can irritate the lips.

Lanolin is sometimes used by people on [[continuous positive airway pressure]] therapy to reduce irritation with masks, particularly nasal pillow masks that can often create sore spots in the [[nostril]]s.

Lanolin is a popular additive to [[moustache wax]], particularly 'extra-firm' varieties.

Lanolin is used as a primary lubricating component in aerosol-based brass [[lubricant]]s in the ammunition reloading process. Mixed warm 1:12 with highly concentrated [[ethanol]] (usually 99%), the ethanol acts as a carrier which evaporates quickly after application, leaving a fine film of lanolin behind to prevent brass seizing in resizing dies.

Lanolin, when mixed with ingredients such as [[neatsfoot oil]], [[beeswax]] and glycerol, is used in various [[leather]] treatments, for example in some [[saddle soap]]s and in leather care products.

== Standards and legislation ==

In addition to general purity requirements, lanolin must meet official requirements for the permissible levels of [[pesticide]] residues. The Fifth Supplement of the [[United States Pharmacopoeia]] XXII published in 1992 was the first to specify limits for 34 named [[pesticide]]s. A total limit of 40&nbsp;[[parts per million|ppm]] (i.e. 40&nbsp;mg/kg) total pesticides was stipulated for lanolin of general use, with no individual limit greater than 10&nbsp;ppm.<ref name=lanolin_book/>

A second monograph also introduced into the US Pharmacopoeia XXII in 1992 was entitled 'Modified Lanolin'. Lanolin conforming to this monograph is intended for use in more exacting applications, for example on open wounds. In this monograph, the limit of total pesticides was reduced to 3&nbsp;ppm total pesticides, with no individual limit greater than 1&nbsp;ppm.

In 2000, the [[European Pharmacopoeia]] introduced pesticide residue limits into its lanolin monograph. This requirement, which is generally regarded as the new quality standard, extends the list of pesticides to 40 and imposes even lower concentration limits.

Some very high-purity grades of lanolin surpass monograph requirements. New products obtained using complex purification techniques produce lanolin esters in their natural state, removing oxidative and environmental impurities resulting in white, odourless, [[hypoallergenic]] lanolin. These ultra-high-purity grades of lanolin are ideally suited to the treatment of dermatological disorders such as [[eczema]] and on open wounds.<ref>{{cite journal |last1=Arden Jones |first1=M. R. |last2=Steel |first2=I. |last3=Powell |first3=S. M. |journal=British Journal of Dermatology |volume=147 |issue=Suppl. 62 |pages=71 |date=July 2002 |doi=10.1046/j.1365-2133.147.s62.19.x  |title=British Contact Dermatitis Group: Summaries of Papers }}</ref>

Lanolin attracted attention owing to a misunderstanding concerning its sensitising potential.<ref name="steel">{{cite journal |last=Steel |first=I. |title=Lanolin Allergy: Hype or Hypersensitivity? |journal=Journal of the National Eczema Society (Exchange) |issue=75 |pages=16–17 |date=1994 }}</ref> A study carried out at New York University Hospital in the early 1950s had shown about 1% of patients with dermatological disorders were allergic to the lanolin being used at that time.  By one estimate, this simple misunderstanding of failing to differentiate between the general healthy population and patients with dermatological disorders exaggerates the sensitising potential of lanolin by 5,000–6,000 times.<ref name = steel/><ref>{{cite conference|last1=Steel |first1=I. |last2=White |first2=I. R. |last3=Beck |first3=M. H. |date=1995 |title=Dilemmas in Lanolin Sensitivity |conference=10th International Symposium on Contact Dermatitis |location=[[Nagoya]]}}</ref>

The European [[Cosmetics Directive]], introduced in July 1976, contained a stipulation that cosmetics which contained lanolin should be labelled to that effect. This ruling was challenged immediately, and in the early 1980s, it was overturned and removed from the directive. Despite only being in force for a short period of time, this ruling did harm both to the lanolin industry and to the reputation of lanolin in general.<ref name=steel/> The Cosmetics Directive ruling only applied to the presence of lanolin in cosmetic products; it did not apply to the many hundreds of its different uses in dermatological products designed for the treatment of compromised skin conditions.

Modern analytical methods have revealed lanolin possesses a number of important chemical and physical similarities to human [[stratum corneum]] lipids; the [[lipids]] which help regulate the rate of water loss across the [[epidermis]] and govern the hydration state of the skin.<ref name=lanolin_book/><ref name="Clark93Poster">{{cite report|first1=E. W.|last1=Clark|first2=I.|last2=Steel|title=Poster No.&nbsp;2|publisher=American Academy of Dermatology|location=Washington, DC|date=1993}}</ref><ref name="Clark93">{{cite journal |last1=Clark |first1=E. W. |last2=Steel |first2=I. |journal=Journal of the Society of Cosmetic Chemists |volume=44 |issue=4 |pages=181–195 |date=1993 |title=Investigations into biomechanisms of the moisturizing function of lanolin |url=http://journal.scconline.org/pdf/cc1993/cc044n04/p00181-p00195.pdf |access-date=29 October 2016 |archive-date=29 October 2016 |archive-url=https://web.archive.org/web/20161029114633/http://journal.scconline.org/pdf/cc1993/cc044n04/p00181-p00195.pdf |url-status=live }}</ref>

[[Cryogenic]] [[scanning electron microscopy]] has shown that lanolin, like human stratum corneum lipids, consists of a mass of liquid crystalline material. [[Polarized light microscopy|Cross-polarised light microscopy]] has shown the [[lamellar|multilamellar]] [[Vesicle (biology)|vesicle]]s formed by lanolin are identical to those formed by human stratum corneum lipids. The incorporation of bound water into the stratum corneum involves the formation of multilamellar vesicles.<ref name=lanolin_book/><ref name=Clark93/>

Skin [[bioengineering]] studies have shown the durational effect of the [[emollient]] (skin smoothing) action produced by lanolin is very significant and lasts for many hours. Lanolin applied to the skin at 2&nbsp;mg/cm<sup>2</sup> has been shown to reduce roughness by about 35% after one hour and 50% after two hours, with the overall effect lasting for considerably more than eight hours.<ref name=lanolin_book/> Lanolin is also known to form semiocclusive (breathable) films on the skin.<ref name = barnett/> When applied daily at around 4&nbsp;mg/cm<sup>2</sup> for five consecutive days, the positive moisturizing effects of lanolin were detectable until 72&nbsp;hours after final application.<ref name=lanolin_book/> Lanolin may achieve some of its moisturizing effects by forming a secondary moisture reservoir within the skin.<ref name=Clark93Poster/><ref name=Clark93/>

The barrier repair properties of lanolin have been reported to be superior to those produced by both [[Petroleum jelly|petrolatum]] and [[glycerol]].<ref name=lanolin_book/> In a small clinical study conducted on volunteer subjects with terribly dry ([[Xeroderma|xerotic]]) hands, lanolin was shown to be superior to petrolatum in reducing the signs and symptoms of dryness and [[Skin condition#Secondary lesions|scaling]], cracks and abrasions, and pain and itch. In another study, a high purity grade of lanolin was found to be significantly superior to petrolatum in assisting the healing of superficial wounds.

==References==

{{reflist}}

== External links ==

* {{MedlinePlusEncyclopedia|002663|Lanolin poisoning}}

{{E number infobox 910-919}}

{{Use dmy dates|date=March 2020}}

[[Category:Animal glandular products]]
[[Category:Waxes]]
[[Category:Non-petroleum based lubricants]]
[[Category:By-products]]