5-hydroxy-L-Tryptophan

5-hydroxy-L-Tryptophan (5-HTP) is an intermediate in the biosynthesis of serotonin from tryptophan.{14424} When injected systemically in animals, 5-HTP is converted to serotonin and has both peripheral and central nervous system effects.{32456,32457,21469} In ex vivo studies, 5-HTP can be metabolized to melatonin with circadian rhythmicity, using serotonin as an intermediate.{32455} 5-HTP can also be synthesized by gut microbiota and acts as an activator of the aryl hydrocarbon receptor.{32458}