The Index · Polyol humectant
Glycerin
Glycerin
The workhorse humectant: cheap, endlessly studied, and better than the fashionable alternatives at holding water.
StrongMultiple RCTs, consistent
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Glycerin is a small three-carbon polyol and the skin's own humectant — aquaporin-3 channels transport it into the epidermis, where it helps regulate hydration, desquamation and lipid organisation[1].
The evidence
Decades of work show glycerin increases stratum corneum water content, speeds barrier recovery after irritation, and improves the appearance of dry skin[1]. In atopic dermatitis, 20 % glycerin performed as well as 4 % urea with fewer sensations of stinging[2].
It is unglamorous, which is why marketing leads with hyaluronic acid instead. Formulators know better: glycerin is usually the reason a moisturiser works.
Evidence by claim
Graded separately; the entry grade is the best-supported claim
Improves dry skin in atopic dermatitis comparably to urea[2]
ModerateSafety & limits
Source and region, always
all — No restrictions; one of the safest ingredients in the category. CA US EU UK
Sources · 2
Numbered as cited in the text
- [1]Fluhr JW, Darlenski R, Surber C. Glycerol and the skin: holistic approach to its origin and functions. British Journal of Dermatology (2008)doi:10.1111/j.1365-2133.2008.08643.x
- [2]Lodén M, Andersson AC, Andersson C, et al.. Instrumental and dermatologist evaluation of the effect of glycerine and urea on dry skin in atopic dermatitis. Skin Research and Technology (2001)doi:10.1034/j.1600-0846.2001.70405.x
Revision history
16 Sept 2026Entry createdTheSkindex Desk