Glycerin

Clinics in Dermatology · 2012 · systematic review

Review of how moisturizers affect the epidermal barrier: humectants such as glycerin increase stratum corneum hydration and can strengthen barrier function and resistance to irritation, although effects depend on formulation and some moisturizers may weaken the barrier; supports well-formulated glycerin-containing emollients for dry, barrier-impaired skin.

British Journal of Dermatology · 2008 · systematic review

Review establishing glycerin as the gold standard humectant: attracts water to stratum corneum via hydrogen bonding, improves skin mechanical properties (elasticity, pliability), enhances desmosome degradation for smooth desquamation, and modulates aquaporin-3 channels; effective at 2-20% in topical formulations

Dermatologic Therapy · 2004 · systematic review

Comprehensive review of moisturization mechanisms: glycerin contributes to corneocyte hydration by replacing lost natural moisturizing factor (NMF) components; maintains stratum corneum fluidity at low humidity; superior humectant performance vs propylene glycol, sorbitol, and urea in controlled comparisons

Skin Pharmacology and Physiology · 2007 · rct · n=30

Placebo-controlled, double-blind RCT (n=24, atopic dermatitis): a glycerol-based emollient applied twice daily for 4 weeks significantly improved stratum corneum hydration and restored epidermal barrier function versus a glycerol-free placebo; no significant differences from placebo were found for erythema, SCORAD, or local severity scores.

Acta Dermato-Venereologica · 2002 · rct · n=97

RCT (n=197 atopic dermatitis patients): a 20% glycerin cream, its glycerin-free base, and a 4% urea/4% NaCl cream were applied daily for 30 days. Glycerin and the comparators had equal effects on skin dryness; glycerin caused significantly less smarting than the urea-saline cream (10% vs 24%, p<0.0006).

International Journal of Cosmetic Science · 2001 · rct · n=40

Bilateral double-blind study (n=17): a cream containing 20% glycerin significantly increased skin hydration (corneometer) versus its vehicle, but did not significantly affect transepidermal water loss or skin sensitivity to sodium lauryl sulfate-induced irritation—glycerin's benefit was on hydration, not barrier function.