Betaine HCL What Is Betaine HCL? Betaine hydrochloride (Betaine HCL) is an acidic form of betaine, a vitamin-like substance found in grains and other foods. It is an excellent source of hydrochloric acid – an acidifying compound naturally produced by the stomach during the digestion of food. https://www.nationalnutrition.ca/digestive-supplements/digestive-acids/betaine-hcl.html #betainehydrochloride