(PEA) is an organic compound, natural monoamine alkaloid, and trace amine that acts as a stimulant to the central nervous system in humans. Phenethylamine regulates monoamine neurotransmission in the brain by binding to trace amine-associated receptor 1 (TAAR1) and inhibiting vesicular monoamine transporter 2 (VMAT2). It also functions as a neurotransmitter in the human central nervous system to a lesser extent. In mammals, phenethylamine is synthesized from the amino acid L-phenylalanine via enzymatic decarboxylation by the enzyme aromatic L-amino acid decarboxylase.In addition to mammals, phenethylamine can be found in a variety of other organisms and foods, including chocolate, especially after microbial fermentation.
Phenethylamine is sold as a dietary supplement for purported mood and weight loss-related therapeutic benefits; however, a significant amount of orally ingested phenethylamine is metabolized in the small intestine by monoamine oxidase B (MAO-B) and then aldehyde dehydrogenase (ALDH), which converts it to phenylacetic acid. This means that in order for significant concentrations to reach the brain, the dosage must be higher than in other methods of administration. Some authors speculated on its role in people falling in love without providing any direct evidence.
Phenethylamines, or more precisely, substituted phenethylamines, are a class of phenethylamine derivatives that contain phenethylamine as a “backbone”; in other words, this chemical class includes derivative compounds formed by substituting one or more hydrogen atoms in the phenethylamine core structure. The class of substituted phenethylamines includes all substituted amphetamines and substituted methylenedioxyphenethylamines (MDxx), as well as many drugs that act as empathogens, stimulants, psychedelics, anorectics, bronchodilators, decongestants, and/or antidepressants, among others.
Phenethylamine is produced by a wide variety of species throughout the plant and animal kingdoms, including humans; it is also produced by certain fungi and bacteria (genera: Lactobacillus, Clostridium, Pseudomonas, and the family Enterobacteriaceae) and acts as a potent antimicrobial against certain pathogenic strains of Escherichia coli (e.g., the O157:H7 strain).
The amino-group of phenethylamine is attached to a benzene ring via a two-carbon, or ethyl group, making it a primary amine. At room temperature, it is a colorless liquid with a fishy odor that is soluble in water, ethanol, and ether. It has a density of 0.964 g/ml and a boiling point of 195°C. It combines with carbon dioxide in the presence of air to form a solid carbonate salt. Phenethylamine has a strong basicity of pKb = 4.17 (or pKa = 9.83) when measured with the HCl salt, and it forms a stable crystalline hydrochloride salt with a melting point of 217 °C.