5-Hydroxytryptophan

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

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.

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.

Learn more

 * Wikipedia - 5-Hydroxytryptophan