Melatonin is a member of the class of acetamides that is acetamide in which one of the hydrogens attached to the nitrogen atom is replaced by a 2-(5-methoxy-1H-indol-3-yl)ethyl group. It is a hormone secreted by the pineal gland in humans. It has a role as a hormone, an anticonvulsant, an immunological adjuvant, a radical scavenger, a central nervous system depressant, a human metabolite, a mouse metabolite and a geroprotector. It is a member of acetamides and a member of tryptamines. It is functionally related to a tryptamine.