Mechanisms of Action
5-HT
Serotonin
A neurotransmitter regulating mood, sleep, appetite, and the precursor to melatonin.
Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter synthesized from the amino acid tryptophan. Approximately 95% of serotonin is produced in the gut, with the remaining 5% in the brain. Serotonin regulates mood, anxiety, appetite, pain perception, and gastrointestinal motility. Crucially, serotonin is the biochemical precursor to melatonin — the conversion occurs in the pineal gland via the enzyme aralkylamine N-acetyltransferase. This serotonin-melatonin pathway is why adequate tryptophan and vitamin B6 (required cofactors) influence both mood and sleep quality.