<unk>  <unk>  is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain,<unk>  regulates monoamine neurotransmission by binding to trace amine-associated receptor 1 (TAAR1) and inhibiting vesicular monoamine transporter 2 (VMAT2) in monoamine neurons. To a lesser extent, it also acts as a neurotransmitter in the human central nervous system. In mammals,<unk>  is produced from the amino acid L-phenylalanine by the enzyme aromatic L-amino acid decarboxylase via enzymatic decarboxylation. In addition to its presence in mammals,<unk>  is found in many other organisms and foods, such as chocolate, especially after microbial fermentation.<unk>  is sold as a dietary supplement for purported mood and weight loss-related therapeutic benefits; however, in orally ingested<unk> , a significant amount 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 for significant concentrations to reach the brain, the dosage must be higher than for other methods of administration. Some authors postulated its role in people's falling-in-love without substantiating it with any direct evidence.<unk> s, or more properly, substituted<unk> s, are the group of<unk>  derivatives that contain<unk>  as a "backbone"; in other words, this chemical class includes derivative compounds that are formed by replacing one or more hydrogen atoms in the<unk>  core structure with substituents. The class of substituted<unk> s includes all substituted amphetamines, and substituted methylenedioxyphenethylamines (MDxx), and contains many drugs which act as empathogens, stimulants, psychedelics, anorectics, bronchodilators, decongestants, and/or antidepressants, among others.
Phenethylamine
Chlorphenamine
Methoxyphenamine
Phenoxyethanol
Pseudophenmetrazine
Trimethobenzamide
Carctol
Triprolidine