5-Hydroxytryptophan

5-Hydroxytryptophan (5-HTP) is a precursor to the neurotransmitter serotonin.

Theory
The reaction that causes 5-HTP to become serotonin requires the action of the enzyme aromatic-L-amino-acid decarboxylase (AADC). Vitamin B6 is also required as a cofactor. The same enzyme catalyzes a number of other reactions, including:


 * L-DOPA to dopamine
 * L-phenylalanine to phenethylamine
 * L-tyrosine to tyramine
 * L-histidine to histamine
 * L-tryptophan to tryptamine

5-HTP has been shown to increase serotonin levels in the central nervous system.

Evidence
Reports about serotonin levels in ME/CFS patients are mixed. One study hypothesized, based off of their findings on tryptophan, that ME/CFS patients fell into two groups: a group with high brain serotonin, and a group with normal serotonin. Multiple studies have found high, low, or normal serotonin, due either to different diagnostic criteria or ME/CFS subgroups.

Risks and safety
Because 5-HTP increases brain serotonin, users are at risk for serotonin syndrome if they also take other medications which increase brain serotonin,. Medications which come under this category and which are commonly taken be ME/CFS patients include: Other medications, including other supplements, may also increase brain serotonin - make sure you tell your pharmacist and your doctor if you are taking 5-HTP.
 * Anti-depressant drugs
 * Dextromethorphan (Robitussin DM, and others)
 * Tramadol (Ultram)

Learn more

 * Wikipedia - 5-Hydroxytryptophan