Betaine, the trimethyl derivative of glycine, is an endogenous anti-inflammatory metabolite of plants and animals. Betaine acts as an osmoprotectant against salt and temperature stress in plants. In animals, betaine is the product of choline oxidation or is obtained from from nutritional sources. Mechanistically, betaine ameliorates sulfur amino acid metabolism against oxidative stress, inhibits nuclear factor-κB activity and NLRP3 inflammasome activation, regulates energy metabolism, and mitigates endoplasmic reticulum stress and apoptosis. Betaine hydrochloride Betaine hydrochloride is marketed as a complementary medicine for hypochlorhydria.