Tryptophan 100% pure tryptophan powder, an essential amino acid used by the body to produce serotonin & melatonin. Tryptophan is an essential amino acid, meaning it can’t be produced by your body, & must be obtained through your diet or nutritional supplements. Our Tryptophan comes in powdered form & is great for mixing in with your favourite shake formula to up your intake of tryptophan. Tryptophan is best known as a precursor for the production of serotonin & melatonin in the body.