Serotonin (C₁₀H₁₂N₂O) — Properties, Uses & Safety

Overview

Serotonin (C10H12N2O), chemically known as 5-hydroxytryptamine or 5-HT, is one of the most important neurotransmitters in the human body, often called the feel-good molecule for its role in regulating mood and emotional well-being. With a molar mass of 176.21 g/mol, serotonin is a monoamine neurotransmitter derived from the essential amino acid tryptophan through a two-step biosynthetic pathway involving hydroxylation and decarboxylation. Structurally, serotonin features an indole ring system (a bicyclic aromatic structure consisting of a benzene ring fused to a pyrrole ring) with a hydroxyl group at the 5-position and an ethylamine side chain. This indole core is shared with many other biologically active compounds, including the amino acid tryptophan, the hormone melatonin, and the psychedelic compound psilocybin. Surprisingly, about 90% of the body's serotonin is found not in the brain but in the gastrointestinal tract, where it regulates intestinal motility and function. In the brain, serotonin modulates mood, anxiety, happiness, sleep-wake cycles, appetite, memory, and learning. Low serotonin levels are associated with depression, anxiety disorders, and obsessive-compulsive disorder. Selective serotonin reuptake inhibitors (SSRIs) like fluoxetine (Prozac) and sertraline (Zoloft) are among the most prescribed medications worldwide — they work by blocking the reabsorption of serotonin in the synapse, increasing its availability to bind to postsynaptic receptors. Serotonin is also the precursor to melatonin, the hormone that regulates circadian rhythms and sleep. In the cardiovascular system, serotonin released by platelets helps regulate blood clotting and vasoconstriction. GHS classifications for pure serotonin include irritant and health hazard warnings. For chemistry students, serotonin is a fascinating molecule for exploring heterocyclic aromatic chemistry (the indole ring system), biosynthetic pathways (enzymatic hydroxylation and decarboxylation), neurotransmitter chemistry and receptor binding, the relationship between molecular structure and biological activity, and the chemistry of mental health. It demonstrates how a relatively small organic molecule can have profound effects on human behavior and well-being, making it one of the most captivating compounds at the intersection of chemistry, biology, and psychology.

IUPAC Name

3-(2-aminoethyl)-1H-indol-5-ol

CAS Number

50-67-9

PubChem CID

5202

Molecular Formula

C₁₀H₁₂N₂O

Molar Mass

176.215 g/mol

State at STP

solid

Appearance

White to light pink crystalline solid