L-proline (proline for short) is one of the 18 amino acids synthesized by the human body. It is colorless to white crystal or crystalline powder at room temperature, slightly smelly, slightly sweet, easily soluble in water, insoluble in ethanol, insoluble in ether and n-butanol. Amino acids are a general term for a class of organic compounds containing amino and carboxyl groups. The existence of amino acids in the human body not only provides important raw materials for the synthesis of proteins, but also provides a material basis for promoting growth, normal metabolism and maintaining life.