Tryptophan is an essential amino acid. It is obtained in the diet from bananas, beans, brewer’s yeast, cottage cheese, dairy products, dates, eggs, fish, legumes, whole grains etc.

Tryptophan is required for the production of vitamin B3 (niacin), which is vital for the brain to manufacture serotonin. Tryptophan is a precursor of the transmitter serotonin, and its ability to boost serotonin levels suggests that it may help to improve mood in people who are low or depressed. Tryptophan may also be of use to people suffering from insomnia, as serotonin is regarded as an effective sleep-inducing agent. Tryptophan also boots the release of growth hormones and helps to suppress the appetite.

Signs and symptoms of tryptophan deficiency include apathy, loss of pigmentation in hair, edema, lethargy, liver damage, muscle loss, fat loss, skin lesions, weakness and slowed growth in children.

Therapeutic doses range from 1.5-6 g per day, depending upon need. Tryptophan is best taken between meals with a low-protein food, for example, bread.

People taking monoamine oxidase inhibitors (MAOIs) should be cautious when taking tryptophan as it can increase the risk of central nervous system excitation. People with kidney disease or liver disease should consult their doctor before taking tryptophan.