Editing Humectant (section)

===Cosmetics===
Humectants are frequently used in cosmetics as a way of increasing and maintaining moisture in the skin and hair, in  products including shampoo, conditioner, frizz serum, lotions, creams, lip treatments, cleansers, after-sun lotion, and some soaps or body lotions. As hygroscopic moisturizers, humectants work by attracting water to the upper layer of the skin (stratum corneum).<ref>Making Cosmetics, Inc. http://www.makingcosmetics.com/articles/13-humectants-moisturizing-agents-in-cosmetics.pdf {{Webarchive|url=https://web.archive.org/web/20150319054049/http://www.makingcosmetics.com/articles/13-humectants-moisturizing-agents-in-cosmetics.pdf |date=2015-03-19 }} (Accessed 5/10/14{{Clarify|reason=ambiguous date format|date=November 2016}})</ref> All humectants have common hydroxyl groups which allow them to participate in hydrogen bonding and attract water. This process attracts moisture from the outer layer of the skin or, in high humidity, from the atmosphere. The moisture is then trapped against the [[Epidermis (skin)|epidermis]] or the shaft of the hair, depending on where the humectant is applied. Various humectants have different ways of behaving because they differ in water binding capacity at different humidities.<ref>Elsner, P., Maibach, H. (2005) Cosmecuticals and Active Cosmetics – Drugs Versus Cosmetics.</ref>

Humectants used in cosmetics include [[triethylene glycol]],<ref>{{cite journal | year = 2006 | title = Final Report on the Safety Assessment of Triethylene Glycol and PEG-41 | journal = International Journal of Toxicology | volume = 25 | issue = 2_suppl| pages = 121–138 | doi = 10.1080/10915810600964642 | pmid = 17090481 | s2cid = 208154098 }}</ref> [[Tripropylene|tripropylene glycol]],<ref>{{cite journal |author1=Fiume M. M. |author2=Bergfeld W. F. |author3=Belsito D. V. |author4=Hill R. A. |author5=Klaassen C. D. |author6=Liebler D. |author7=Andersen F. | year = 2012 | title = Safety Assessment of Propylene Glycol, Tripropylene Glycol, and PPGs as Used in Cosmetics | journal = International Journal of Toxicology | volume = 31 | issue = 5| pages = 245S–260S | doi = 10.1177/1091581812461381 |pmid=23064775 |s2cid=24754435 |doi-access=free }}</ref> [[propylene glycol]], and [[Polypropylene glycol|PPGs]]. Other popular humectants in cosmetics include [[glycerin]], [[sorbitol]] (sugar alcohol), hexylene and butylene glycol, urea, and collagen.<ref>{{cite journal |author1=Peng Y. |author2=Glattauer V. |author3=Werkmeister J. A. |author4=Ramshaw J. A. M. | year = 2004 | title = Evaluation for collagen products for cosmetic application | journal = International Journal of Cosmetic Science | volume = 26 | issue = 6| page = 313 | doi = 10.1111/j.1467-2494.2004.00245_2.x |citeseerx=10.1.1.504.6688 }}</ref> Glycerin is one of the most popular humectants used because it produces the desired result fairly frequently and is low in cost. A category of humectants called nanolipidgels allow skin to retain moisture, but also possess antifungal properties.<ref>{{cite journal|title=Nanolipidgel for enhanced skin deposition and improved antifungal activity|first1=Preeti|last1=Wavikar|first2=Pradeep|last2=Vavia|date=1 March 2013|journal=AAPS PharmSciTech|volume=14|issue=1|pages=222–233|doi=10.1208/s12249-012-9908-y|pmid=23263751|pmc=3581678}}</ref> Scientists are also working to discover different types of humectants; a study published in 2011 concluded that extracts from wine cakes have the potential to be used as a humectant in cosmetics.<ref>{{cite journal |author1=Chiang H. |author2=Ko Y. |author3=Shih I. |author4=Wen K. | title = Development of Wine Cake as a Skin-Whitening Agent and Humectant | journal = Journal of Food & Drug Analysis | volume = 19 | issue = 2| pages = 223–229 }}</ref>

Humectants have been added to skin moisturizing products to treat [[xerosis]]. Some moisturizers tend to weaken the skin barrier function, but studies on xerosis have proven that moisturizers containing humectants increase desired moisturizing effects on the affected area without damage to the skin barrier function.<ref name=Loden>{{cite journal | author = Lodén, M., Scheele, J., & Michelson, S. | date = 2013 | title = The influence of a humectant-rich mixture on normal skin barrier function and on once- and twice-daily treatment of foot xerosis. A prospective, randomized, evaluator-blind, bilateral and untreated-control study | journal = Skin Research & Technology | volume = 19 | issue = 4 | pages = 438–445}}</ref> In this xerosis treatments study, some "smarting and stinging" was also reported from the use of humectant-rich treatment products.<ref name=Loden/>

When the humectant glycerol was added to soaps for the cleansing of wounds, similar effects were found. There was an increase in moisture in the areas that the soap was applied, however, "further consideration of conditioning the use of glycerol to improve the absorption of exudates from wounds for an advanced wound healing is needed."<ref>{{cite journal | author = Gwon, H., Lim, Y., Nho, Y., & Baik, S. | date = 2010 | title = Humectants effect on aqueous fluids absorption of γ-irradiated PVA hydrogel followed by freeze thawing | journal = Radiation Physics & Chemistry | volume = 79 | issue = 5 | pages = 650–653 | doi=10.1016/j.radphyschem.2009.12.011| bibcode = 2010RaPC...79..650G }}</ref> The healing properties of humectants are therefore uncertain.

Humectants are also added to toothpaste (dentifrice) to stop the product drying out and cracking in the tube.  Sorbitol is commonly used as this also contributes a sweet flavour to the toothpaste without contributing to tooth decay.<ref>{{Cite web|url=https://www.colgate.com/en-us/oral-health/basics/selecting-dental-products/what-is-in-toothpaste-five-ingredients-and-what-they-do-0814|title=What is in Toothpaste? Five Ingredients and What They do}}</ref>