Tyramine (4-hydroxyphenethylamine; para-tyramine, mydrial or uteramin) is a naturally occurring monoamine compound and trace amine derived from the amino acid tyrosine. Tyramine acts as a catecholamine releasing agent. Notably, however, it is unable to cross the blood-brain barrier, resulting in only nonpsychoactive peripheral sympathomimetic effects. A hypertensive crisis can result from ingestion of tyramine-rich foods in conjunction with monoamine oxidase inhibitors (MAOIs).