4-HO-NiPT, also known as 4-hydroxy-N-isopropyltryptamine, is a serotonin receptor modulator and putative psychedelic drug of the tryptamine and 4-hydroxytryptamine families related to psilocin (4-HO-DMT). It is an analogue of 4-HO-MiPT (miprocin) and 4-HO-DiPT (iprocin) and a derivative of norpsilocin (4-HO-NMT) and 4-HO-NET. The drug has been encountered online as a possible novel designer drug.
4-HO-NiPT was not included nor mentioned in Alexander Shulgin's book TiHKAL (Tryptamines I Have Known and Loved).
4-HO-NiPT shows affinity for serotonin receptors, including for the serotonin 5-HT<sub>1D</sub>, 5-HT<sub>1E</sub>, 5-HT<sub>2A</sub>, 5-HT<sub>2B</sub>, 5-HT<sub>2C</sub>, 5-HT<sub>6</sub>, and 5-HT<sub>7</sub> receptors (K<sub>i</sub> = 229âÂÂ2,461nM). Conversely, it did not show affinity for the serotonin 5-HT<sub>1B</sub> or 5-HT<sub>5A</sub> receptors, whereas the serotonin 5-HT<sub>1A</sub> receptor was not reported. 4-HO-NiPT is a partial agonist of the serotonin 5-HT<sub>2A</sub>, 5-HT<sub>2B</sub>, and 5-HT<sub>2C</sub> receptors, with () values of 24nM (88.4%), 188nM (69.9%), and 963nM (45.2%), respectively. It was also a weak agonist of other serotonin receptors, including the serotonin 5-HT<sub>1B</sub>, 5-HT<sub>1E</sub>, 5-HT<sub>1F</sub>, and 5-HT<sub>7A</sub> receptors ( = 1,400âÂÂ23,000nM, = 20.4âÂÂ123%), but not of the 5-HT<sub>1A</sub>, 5-HT<sub>1D</sub>, 5-HT<sub>4</sub>, 5-HT<sub>5A</sub>, or 5-HT<sub>6</sub> receptors.
In contrast to norpsilocin, but similarly to psilocin and certain other N-monoalkyltryptamines like 4-HO-NET, 4-HO-NPT, 4-HO-NALT, and 4-HO-NBnT, the drug produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents. It showed 30-fold lower potency than psilocin in this action in mice, but produced about the same maximal response. Similarly to 4-HO-NiPT, other N-monoalkyltryptamines were also much less potent than psilocin, in the range of 10- to 26-fold less potent. In addition to the head-twitch response, 4-HO-NiPT produces hypothermia in rodents.
4-HO-NiPT is a known metabolite of 4-AcO-DiPT and presumably also of 4-HO-DiPT.
The chemical synthesis of 4-HO-NiPT has been described.
Analogues of 4-HO-NiPT include 4-hydroxytryptamine (4-HT or 4-HO-T), 4-HO-MiPT (miprocin), 4-HO-DiPT (diprocin), psilocin (4-HO-DMT), norpsilocin (4-HO-NMT), 4-HO-NET, 4-HO-NPT, 4-HO-NALT, and 4-HO-NBnT, among others.
4-HO-NiPT was first described in the scientific literature, as a metabolite of 4-AcO-DiPT, in 2022. Subsequently, its synthesis was described in 2023 and its pharmacology was reported in 2024. The drug was reported as a possible novel designer drug online in 2022.