Tyramine

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. When tyramine-rich foods are ingested in conjunction with a monoamine oxidase inhibitor (MAOI), tyramine is responsible for the so-called "cheese effect" sometimes seen with their use.