L-tryptophan

L–tryp·to·phan

noun \ˈel-ˈtrip-tə-ˌfan\

Definition of L-TRYPTOPHAN

: the levorotatory form of tryptophan that is a precursor of serotonin and was formerly used in some health food preparations in the belief that it promoted sleep and relieved depression—see eosinophilia-myalgia syndrome