Abstract
5-Hydroxytryptophan (5-HTP) is the intermediate metabolite of the amino acid L-tryptophan (LT) in the serotonin pathway. Therapeutic use of 5-HTP bypasses the conversion of LT into 5-HTP by the enzyme tryptophan hydrolase, which is the rate limiting step in the synthesis of serotonin. Tryptophan hydrolase can be inhibited by numerous factors, including stress, insulin resistance, vitamin B6 deficiency, and insufficient magnesium. In addition, these same factors can increase the conversion of LT to kynurenine via tryptophan oxygenase, making LT unavailable for serotonin production.
