GlycerinvsPanthenol (Pro-Vitamin B5)

Glycerin (glycerol) is a small three-carbon polyol (92 Da) that penetrates the stratum corneum via intercellular lipid and transcellular routes. It acts as a humectant through osmotic mechanisms—creating a concentration gradient that draws water from the atmosphere (when humidity >65%) and from deeper epidermal layers. Glycerin upregulates aquaporin-3 (AQP3), a glycerol-permeable water channel in keratinocyte membranes that facilitates water and glycerol transport. It supports the natural moisturizing factor (NMF)—amino acids, lactate, and urea that maintain stratum corneum water-holding capacity. Glycerin modulates keratinocyte differentiation and may enhance lipid lamellae organization. Mild antimicrobial activity occurs through osmotic stress. Clinical studies demonstrate hydration efficacy comparable to or exceeding hyaluronic acid.

Panthenol (D-pantothenic acid alcohol) penetrates the stratum corneum and is converted to pantothenic acid (vitamin B5) by pantetheinase and alkaline phosphatase enzymes in the skin. Pantothenic acid is a precursor to coenzyme A (CoA), which is required for the synthesis of fatty acids (via acetyl-CoA carboxylase and fatty acid synthase) that form the ceramides, cholesterol, and free fatty acids of the stratum corneum lipid barrier. This supports barrier repair, improves lamellar structure, and reduces transepidermal water loss (TEWL). Panthenol has direct humectant properties—its hydroxyl groups attract and bind water in the stratum corneum. It stimulates fibroblast proliferation and migration, accelerating wound healing and re-epithelialization. Panthenol may also have mild anti-inflammatory effects. As a provitamin, it is stable in formulations and well-tolerated. The Bepanthen/Bepanthol healing creams leverage these mechanisms for wound care and barrier repair.