Glycerol

What it is and how it works. Glycerol (glycerin) is a small trihydroxy alcohol that works as a humectant. It draws water into the stratum corneum and holds it there, in the same way as urea and the skin’s own Natural Moisturising Factor. In a moisturiser it complements the occlusives (such as Petrolatum and liquid paraffin) that slow evaporation (AAD guideline, Eichenfield 2014). This is why it appears in many ordinary pharmacy and NHS emollients. For example, Doublebase Gel (isopropyl myristate 15%, liquid paraffin 15%) lists glycerol as an excipient and is licensed for infants and children (emc SmPC). Glycerol is a standard pharmaceutical ingredient, not a “natural remedy”. Glycerol [part-of] Emollient Therapy Glycerol [relates] Natural Moisturising Factor

Evidence. In the only placebo-controlled trial of glycerol on its own (Breternitz 2008), 24 patients with AD applied 20% glycerol cream to one side and glycerol-free vehicle to the other, twice daily for 4 weeks. Stratum corneum hydration and barrier function improved significantly on the glycerol side, but erythema, SCORAD and local severity did not differ, and both sides improved with regular emollient use. The 2017 Cochrane emollients review included three studies of glycerol moisturisers against vehicle or placebo. In one (134 participants), more participants reported improvement (RR 1.22, 95% CI 1.01–1.48; moderate quality). In another (249 participants), investigator-rated SCORAD fell slightly (MD −2.20; high certainty), below the minimal important difference. Adverse events did not increase (2 studies, RR 0.90). Most other trial evidence is for glycerol combined with paraffin or petrolatum, where the effects appear additive (Wollenberg 2025 review). Cochrane [supports] Glycerol Glycerol [treats] Atopic Dermatitis

Conflict: [Breternitz, 2008] found no significant difference in SCORAD between 20% glycerol cream and its vehicle. [Cochrane, 2017] reports high-certainty evidence of a small SCORAD reduction (MD −2.20) for glycerol versus control. The Cochrane SCORAD estimate comes from a single larger trial (249 participants) and is the stronger evidence, but the gain is below most clinically important thresholds. Unresolved — add to open_questions.

Glycerol versus urea, and toddler practicalities. Loden’s trials compared glycerol with urea. In one (109 patients), urea cream did better than 20% glycerol. In a larger trial (197 patients), the two improved dryness to a similar degree, but glycerol caused less “smarting” (Wollenberg 2025). Because stinging is a common reason toddlers refuse moisturiser, glycerol-containing products are a reasonable everyday choice for 1–4-year-olds. The BEE Trial found that no emollient type (lotion, cream, gel or ointment) beat the others. Stinging was reported with 19% of gels compared with 9% of ointments, so if a glycerol gel stings, switching type is sensible. The best product is the one the child accepts and the family applies generously. Glycerol [relates] Urea Creams BEE Trial [relates] Glycerol

Connections

• Urea Creams — alternative humectant; no excess adverse events vs urea’s RR 1.65, source: Cochrane 2017
• Lanolin — humectant alternative for lanolin-allergic patients, source: Cutis 2023
• BEE Trial — gels (often glycerol-containing) equal to other types; 19% stinging, source: Ridd 2022
• Transepidermal Water Loss — glycerol restored barrier function vs vehicle, source: Breternitz 2008
• Natural Moisturising Factor — humectant like the skin’s own NMF, source: AAD guideline (Eichenfield 2014)
• Emollient Therapy — common excipient in standard emollients, e.g. Doublebase Gel, source: emc SmPC