7-Hydroxy-DMT (7-HO-DMT), also known as 7-hydroxy-N,N-dimethyltryptamine, is a serotonin receptor modulator of the tryptamine family related to dimethyltryptamine (DMT). It is the 7-hydroxy derivative of DMT and is a positional isomer of psilocin (4-HO-DMT), bufotenin (5-HO-DMT), and 6-HO-DMT. The drug shows affinity for serotonin receptors in the rat fundus strip. However, it had the lowest serotonin receptor affinity of any other assessed compounds in a series of assessed tryptamines. In a later study, its affinity (K<sub>i</sub>) for the serotonin 5-HT<sub>2A</sub> receptor was >10,000nM. 7-Hydroxy-DMT is said to be biologically active in animals but to show low potency. The drug was first described in the scientific literature by at least 1962. It is a Schedule I controlled substance in the United States as a positional isomer of psilocin.