Hydroxyproline (proline derivative) is an endogenous amino acid included in the basic protein of connective tissue (collagen and elastin), created from the reaction of the enzyme catalysis in the presence of ascorbic acid. It differs from proline by the presence of hydroxyl (OH). It affects the structure of collagen and the proper functioning of connective tissue. The naturally present in animal origin products, processed from connective tissue (e.g. Jelly jelly). In the supplements used in enhancing the proper functioning of the locomotor system (also in the treatment and rehabilitation of injuries and sports injuries), and in supplements of health and beauty category, as a component of collagen hydrolysates and concentrates.