Panthenol is the alcohol form of pantothenic acid (vitamin B5), used in supplements, cosmetics, and some nutritional products as a stable precursor that the body converts to the vitamin. Chemically it is 2,4-dihydroxy-N-(3-hydroxypropyl)-3,3-dimethylbutanamide, most commonly supplied as dexpanthenol, the biologically active enantiomer. In the body it is oxidised to pantothenic acid, a component of coenzyme A, which is central to fatty acid metabolism and energy production. Cosmetic formulators value panthenol as a humectant and conditioning agent for skin and hair, where it is marketed as provitamin B5. In nutrition, pantothenic acid deficiency is rare because the vitamin is widespread in foods, so panthenol’s dietary role is minor, though it appears in B-complex supplements and fortified products.