Panthenol (pro-vitamin B5)

Pro-vitamin B5, precursor of pantothenic acid (vitamin B5), also known as panthenol, is associated, according to available scientific data, with several cosmetic properties of interest.
Hydration and skin comfort: due to its affinity for water and its ability to retain it, panthenol supports skin hydration. In a randomized, double-blind controlled study on 60 volunteers, 2.5% dexpanthenol in a cosmetic formula was linked to improved stratum corneum hydration and reduced TEWL over 7 days compared to placebo.
Skin comfort after exposure to a surfactant: a double-blind controlled study on 25 volunteers highlighted dexpanthenol's role in maintaining hydration after applying a potentially irritating surfactant, associated with visible reduction of discomfort sensations.
Support of visible skin quality over time: in literature, panthenol is linked to skin comfort and visible skin suppleness, contributing to softer, more comfortable-looking skin daily.
Technical note: panthenol exists in two enantiomeric forms D and L. Only D-panthenol (dexpanthenol) is biologically active.

Sources: Topical use of dexpanthenol: a 70th anniversary article, Journal of Dermatological Treatment, 2017; Effect of topically applied dexpanthenol on epidermal barrier function and stratum corneum hydration, Arzneimittelforschung, 2000; Efficacy of dexpanthenol in skin protection against irritation, Contact Dermatitis, 2003.