Taurine, a nonessential amino acid, is found in high concentrations in the white blood cells, skeletal muscles, central nervous system as well as the heart muscles. In adults, but not children, this nutrient can be manufactured from methionine in the body and from cysteine in the liver. Vitamin B6 must be present for these processes to be successful.

Taurine is a nonessential sulfur-containing amino acid that functions with glycine and gamma-aminobutyric acid as a neuroinhibitory transmitter. While taurine does not have a genetic codon and is not incorporated into proteins and enzymes, it does play an important role in bile acid metabolism. Taurine is incorporated into one of the most abundant bile acids, chenodeoxychloic acid where it serves to emulsify dietary lipids in the intestine, promoting digestion.

It is a key ingredient of bile, which in turn is needed for fat digestion, absorption of fat-soluble vitamins as well as the control of cholesterol serum levels in the body. (It is incorporated in the bile acid chenodeoxychloic acid, which emulsify the dietary fats). This nutrient is also used in the proper use of potassium, calcium, as well as sodium in the body, and for maintaining cell membrane integrity. It is thought to be helpful with anxiety, hyperactivity, poor brain function and epilepsy as well as hydrating the brain. Taurine, together with zinc, is also required for proper eye health and vision.

A deficiency may impair vision and problems with fat metabolism may appear, and a theory exists that it may also be involved in epilepsy developing.

Vegans who consume no eggs or dairy products ingest virtually no taurine through their diets, but normally have enough since the body can manufacture the requirements. Children with Down's syndrome may benefit from taurine, and women being treated for breast cancer as well as people with metabolic disorders, since metabolic disorders can cause loss of this nutrient via urine. Diabetics may also benefit from this nutrient, since this disease increases the need for this nutrient.

Taurine is found mostly in meat and fish. Except for infants, the human body is able to make taurine from cysteine—another amino acid.