Crystal structure of serotonin

The title compound, serotonin or 5-hy­droxy­tryptamine (5-HT) [systematic name: 3-(2-amino­eth­yl)-1H-indol-5-ol], C(10)H(12)N(2)O, has one mol­ecule in the asymmetric unit. The conformation of the ethyl­amino side chain is gauche–gauche [C(a)—C(a)—C(m)—C(m) and C(a)—C(m)—C(m)—N (a = aromatic, m = methyl­ene) torsion angles = −64.2 (3) and −61.9 (2)°, respectively]. In the crystal, the mol­ecules are linked into a three-dimensional network by N—H⋯O and O—H⋯N hydrogen bonds.