2-OH-2C-B, also known as 2-O-desmethyl-2C-B (2-DM-2C-B) or as 4-bromo-2-hydroxy-5-methoxyphenethylamine (B-2-HMPEA), is a serotonin receptor modulator of the phenethylamine family related to the 2C psychedelic 2C-B (2,5-dimethoxy-4-bromophenethylamine). It is the 2-O-demethylated analogue of 2C-B. The drug is a potent agonist of the serotonin 5-HT<sub>2A</sub> receptor, with an affinity (K<sub>i</sub>) of 0.92nM, an of 4.3nM, and an of 93%. For comparison, 2C-B had an affinity (K<sub>i</sub>) of 0.64nM, an of 3.3nM, and an of 76%. 2-OH-2C-B is a known metabolite of 2C-B in rodents and humans. The predicted log P of 2-OH-2C-B is 1.5 and of 2C-B is 2.1. The drug was first described in the scientific literature by 2003 and its pharmacology was described by 2013.