Alanine is an amino acid. It is classed as a non-essential amino acid, because the body can naturally make as much as it needs. However, alanine is a very popular sports supplement, because it has been shown to help boost anaerobic endurance.
Alanine's main function in the body is to aid the conversion of glucose into energy, and to remove toxins from the liver. In terms of endurance and high level sports, alanine is important because it is involved in the production of carnosine. Carnosine helps to prevent muscles becoming too acidic – and it's this change of pH in muscles which contributes to muscle fatigue.
Alanine supplements are more effective than supplementing with carnosine alone, as carnosine is broken down in the digestive system and has to be re-made by muscles; it is therefore thought to be more efficient to take alanine.
Once synthesised by the body, alanine is transformed by the liver into pyruvate, which is essential for the regulation of blood sugar. Alanine is therefore sometimes used to help diabetics avoid hypoglycaemia.
Beef, lamb, turkey and chicken are good sources of alanine in the diet. As a supplement, alanine can be taken in powder or tablet form; it's also found as an ingredient in many sports drinks.