5 hydroxy-L-tryptophan is a derivative of the essential amino acid tryptophan. 5-HTP is converted in the liver and brain to the neurotransmitter serotonin, a substance that plays an important role in behavior and mood swings. Increased intake also means increased serotonin levels, which can help with conditions such as depression, anxiety, irritability and other mood disorders. It is also helpful in cases of overeating, but also in headaches. Recommended daily intake has not been set for 5-HTP. The therapeutic dose ranges from 50-100 mg.