For Relaxation Positive Mood & Sleep. L-tryptophan is an essential amino acid and hence cannot be synthesized by the body but must be obtained from food or supplements. Because L-tryptophan is converted to serotonin (5-hydroxytryptamine) and melatonin in the body it plays an important role in promoting relaxation restful sleep and positive mood. L-tryptophan may also help in reducing carbohydrate cravings. Jarrow FORMULAS® L-Tryptophan TryptoPure® is manufactured at a GMP facility via fermentation from vegetable materials. Suitable for vegetarians/vegans.