L-Lysine is an essential amino acid necessary for growth development tissue maintenance and repair.* Jarrow FORMULAS L-Lysine 500 is the hydrochloride (HCl) form of L-Lysine which is twice as stable as the monochloride form. 625 mg of L-Lysine HCl yields 500 mg of elemental L-Lysine.Other products from HerbsPro