Taurine is a semi-essential amino acid and is not incorporated into proteins. Taurine is considered conditionally essential because it cannot be synthesized by infants younger than 4-6 weeks, and it may not be adequately synthesized in patients receiving long-term parenteral nutrition and patients with short-term hypermetabolic conditions. In mammalian tissues, taurine is ubiquitous and is the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. Taurin occurs naturally in fish and meat. The mean daily intake from omnivore diets was determined to be around 58 mg. Taurine is a component of energy drinks, with many contain 1000 mg per serving. In medicine, taurine supplementation demonstrated efficacy in relieving symptoms of heart failure, hepatitis, hypertension and psychotic disorder. Taurine exerts many physiological functions, including membrane stabilization, osmoregulation and cytoprotective effects, antioxidant and anti-inflammatory actions as well as modulation of intracellular calcium concentration and ion channel function. In addition taurine may control muscle metabolism and gene expression, through yet unclear mechanisms. The cellular and biochemical mechanisms mediating the actions of taurine are not fully known.