Monoamine precursor
Monoamine precursors are precursors of monoamines and monoamine neurotransmitters in the body. The amino acids L-tryptophan and L-5-hydroxytryptophan (5-HTP; oxitriptan) are precursors of serotonin and melatonin, while the amino acids L-phenylalanine, L-tyrosine, and L-DOPA (levodopa) are precursors of dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline).