MOLECULE

Phenylethylamine

Phenylethylamine (PEA) is an aromatic amine which has a constitutional isomer (+)-phenylethylamine (1-phenylethylamine), which has two stereoisomers: (R)-(+)-1-phenylethylamine and (S)-(-)-1-phenylethylamine. It is a strongly basic, colorless liquid at room temperature which is soluble in water, ethanol, and ether. Similar to other low-molecular-weight amines, it has a fishy odor. Upon exposure to air, it forms a solid carbonate salt with carbon dioxide. Phenylethylamines can be biosynthesized in mammals from the amino acid phenylalanine by enzymatic decarboxylation. Phenylethylamine is produced after microbial fermentation and is a metabolite of Bacillus, Enterococcus, Pseudomanas and Lactobacillus (PMID: 22953951; PMID: 17307265; PMID: 16630269) and has anti-microbial properties against pathogenic strains of E. coli. It is found in many foods such as chocolate. However, trace amounts from food are quickly metabolized by the enzyme monoamine oxidase (MAO-B) into phenylacetic acid, preventing significant concentrations from reaching the brain. In the human brain, phenylethylamine is a central nervous system stimulant that binds to the human trace amine-associated receptor 1 (hTAAR1) as an agonist (PMID: 27424325). It is a precursor to the neurotransmitter phenylethanolamine. High levels of PEA have been found in the urine of schizophrenics, but it is not significantly elevated in the serum or CSF of schizophrenics (PMID: 7906896, PMID: 7360842). Urinary levels of PEA are significantly lower in children with attention deficit hyperactivity disorder (ADHD) (PMID: 12205654). Phenylethylamine is also a skin irritant and possible sensitizer. PEA is the primary compound found in carnivore urine (especially cat) that repels mice and rats. Quantitative HPLC analysis across 38 mammalian species has shown that PEA production in urine is especially high in carnivores, with some producing >3,000-fold more than herbivores (PMID: 21690383). PEA is also found in Cannabis plants (PMID: 6991645).