Urinary mandelic acid: identified in normal individuals following a single oral load of phenylethylamine

1. An increased urinary mandelic acid was identified by gas-liquid chromatography in the urine of 3 healthy subjects following the oral ingestion of phenylethylamine. 2. The pathway for the formation of mandelic acid from phenylethylamine was suggested to involve the intermediate phenylethanolamine. The basic similarity of the metabolism of phenylethylamine and tyramine was suggested by the excretion of 4.5% of phenulethlamine as mandelic acid which correlated well to a reported 7.2% of p-tyramine excreted as p-hydroxy mandelic acid.