Retinolin

Retinolin is not a term with a distinct, widely recognized chemical definition in standard nomenclature. In scientific literature, the name does not designate a single confirmed compound, and it may reflect a misspelling, a brand name, or an informal shorthand for retinoid-related substances.

Retinol, or vitamin A1 alcohol, is a fat-soluble vitamin involved in vision, cellular growth, and immune function. It has the chemical formula C20H30O and exists in several isomeric forms. In humans, retinol is stored in the liver and can be oxidized to retinal, a key cofactor in the visual cycle, and further oxidized to retinoic acid, which regulates gene expression by activating nuclear receptors (RARs and RXRs). Dietary sources include animal products; provitamin A carotenoids in plants can be converted to retinol in the body. In cosmetics, retinol is used to promote cell turnover and reduce signs of aging, typically formulated at low concentrations to minimize irritation.

Retinoids encompass a broader class of related compounds, including retinoic acid, tretinoin, and isotretinoin. They are used topically for acne and photoaging and, in some cases, systemically for severe skin conditions. Their mechanism involves binding to retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which modulate gene expression and cellular differentiation.

Safety considerations include potential teratogenic risks, so retinoids are generally contraindicated during pregnancy. Topical formulations can cause irritation, dryness, and increased photosensitivity, necessitating gradual introduction and sun protection.

See also: Vitamin A, Retinol, Retinoids.