4-HO-TMT
4-HO-TMT, or 4-OH-TMT, also known as 4-hydroxy-N,N,N-trimethyltryptammonium or as dephosphorylated aeruginascin, is a substituted tryptamine derivative and the active form of aeruginascin (4-PO-TMT), analogously to how psilocin (4-HO-DMT) is the active form of psilocybin (4-PO-DMT). 4-HO-TMT is closely related to bufotenidine, the N-trimethyl analogue of serotonin.