5-Hydroxytryptophan

5-Hydroxytryptophan, also known as 5-HTP and oxitriptan, is a naturally occurring amino acid and chemical precursor as well as a metabolic intermediate in the biosynthesis of the neurotransmitters serotonin and melatonin from tryptophan. It is available over the counter in the United States, United Kingdom, and Canada as a dietary supplement and often used as an antidepressant, sleep aid, and appetite suppressant. In some European countries, it is marketed as a prescription drug for the treatment of major depression.[1]

5-HTP is also used by users of MDMA to reduce the negative after effects that occur during the drug's come down period, including anxiety, depression, and cognitive fatigue.[4] Since 5-HTP is a precursor for the neurotransmitter serotonin and MDMA depletes serotonin levels in the brain, it is believed that taking 5-HTP after coming down will speed the production of serotonin. It is important to not take the 5-HTP until 12 hours after the MDMA was last dosed because combining the two drugs could result in a dangerous and fatal condition called serotonin syndrome.