Chemistry:4-HO-MPT

From HandWiki

4-HO-MPT, also known as 4-hydroxy-N-methyl-N-propyltryptamine or as meprocin, is a psychedelic drug of the tryptamine and 4-hydroxytryptamine families.[1][2] It is a higher homologue of psilocin (4-HO-DMT) as well as the 4-hydroxyl analogue of N-methyl-N-propyltryptamine (MPT).[1][2] The drug is taken orally.[1][2]

It acts as a non-selective serotonin receptor agonist, including of the serotonin 5-HT2A receptor.[3][4] The drug produces psychedelic-like effects in animals.[2][3]

4-HO-MPT was first described in the scientific literature by 1981.[5] It was encountered as a novel designer drug by 2021.[6]

Use and effects

The dose and duration of 4-HO-MPT are listed as "unknown" in Alexander Shulgin's book TiHKAL (Tryptamines I Have Known and Loved).[1] In more recent publications, the dose has been reported to be 20 to 30 mg orally, with a mean dose of 25 mg.[2] In a single trial of 8 mg 4-HO-MPT hydrochloride orally from TiHKAL, it was described as producing visual distortion, vertigo, and slight insomnia.[1]

Interactions

Pharmacology

Pharmacodynamics

4-HO-MPT activities
Target Affinity (Ki, nM)
5-HT1A 106–910 (Ki)
490 (EC50)
90% (Emax)
5-HT1B 224
5-HT1D 170
5-HT1E 246
5-HT2A 71–114 (Ki)
3.8–64a (EC50)
53%a–98% (Emax)
5-HT2B 8 (Ki)
3.4 (EC50)
58% (Emax)
5-HT2C 150–203 (Ki)
46–66a (EC50)
83–100%a (Emax)
5-HT5A 664
5-HT6 48
5-HT7 99
α2A 3,625
α2B 1,844
α2C IA
D2 IA
D3 921
D4, D5 IA
H1 92
H2 IA
M4 IA
σ1 891
σ2 1,166
KOR IA
NR2B 3,658
SERT 910–1,180 (Ki)
575 (IC50)
DAT IA

4-HO-MPT acts as a potent agonist of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors.[3][4] It is a partial or full agonist of the serotonin 5-HT2A receptor, a moderate-efficacy partial agonist of the serotonin 5-HT2B receptor, and a high-efficacy partial agonist of the serotonin 5-HT2C receptor.[3][7] The drug has more than an order of magnitude higher potency as an agonist of the serotonin 5-HT2A and 5-HT2B receptors than as an agonist of the serotonin 5-HT2C receptor.[3] It also interacts with other serotonin receptors such as 5-HT6 and 5-HT7 receptors with high affinity and non-serotonergic targets.[4] Additionally it inhibits serotonin transporter.[8]

4-HO-MPT produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents.[2][3]

Chemistry

Synthesis

The chemical synthesis of 4-HO-MPT has been described.[1]

Analogues

Analogues of 4-HO-MPT include methylpropyltryptamine (MPT), 4-AcO-MPT, 5-MeO-MPT, psilocin (4-HO-DMT), 4-HO-DET (ethocin), 4-HO-DPT (deprocin), 4-HO-MET (metocin), and 4-HO-PiPT (iprocin), among others.[1]

History

4-HO-MPT was first described in the scientific literature by David Repke and colleagues in 1981.[5] Subsequently, its effects in humans were described by Alexander Shulgin in his 1997 book TiHKAL (Tryptamines I Have Known and Loved).[1] The drug was encountered as a novel designer drug by 2021.[6]

Society and culture

International

4-HO-MPT is not scheduled by the United Nations' Convention on Psychotropic Substances.[9]

Canada

4-HO-MPT is not an explicitly nor implicitly controlled substance in Canada as of 2025.[10]

United States

4-HO-MPT is not scheduled at the federal level in the United States,[11] but it is possible that 4-HO-MPT could legally be considered an analog of psilocin, in which case, sales or possession with intent for human consumption could potentially be prosecuted under the Federal Analogue Act.[12]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 4-HO-MPT Entry in TIHKAL @ Erowid.org
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 "Correlation between the potency of hallucinogens in the mouse head-twitch response assay and their behavioral and subjective effects in other species". Neuropharmacology 167. May 2020. doi:10.1016/j.neuropharm.2019.107933. PMID 31917152. PMC 9191653. http://usdbiology.com/cliff/Courses/Advanced%20Seminars%20in%20Neuroendocrinology/Serotonergic%20Psychedelics%2020/Halberstadt%2020%20Neuropharm%20potency%20of%20hallucinogens%20%20head-twitch.pdf. "Table 4 Human potency data for selected hallucinogens. [...]". 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "Investigation of the Structure-Activity Relationships of Psilocybin Analogues". ACS Pharmacology & Translational Science 4 (2): 533–542. April 2021. doi:10.1021/acsptsci.0c00176. PMID 33860183. 
  4. ↑ 4.0 4.1 4.2 "Receptor Binding Profiles for Tryptamine Psychedelics and Effects of 4-Propionoxy-N,N-dimethyltryptamine in Mice". ACS Pharmacology & Translational Science 6 (4): 567–577. April 2023. doi:10.1021/acsptsci.2c00222. PMID 37082754. 
  5. ↑ 5.0 5.1 "Psilocin analogs II. Synthesis of 3‐[2‐(dialkylamino)ethyl‐, 3‐[2‐( N ‐methyl‐ N ‐alkylamino)ethyl]‐, and 3‐[2‐(cycloalkylamino)ethyl]indol‐4‐ols"]. Journal of Heterocyclic Chemistry 18 (1): 175–179. 1981. doi:10.1002/jhet.5570180131. ISSN 0022-152X. https://onlinelibrary.wiley.com/doi/10.1002/jhet.5570180131. Retrieved 9 October 2025. 
  6. ↑ 6.0 6.1 "Identification of six tryptamine derivatives as designer drugs in illegal products". Forensic Toxicology 39 (1): 248–258. 2021. doi:10.1007/s11419-020-00556-5. ISSN 1860-8965. http://link.springer.com/10.1007/s11419-020-00556-5. Retrieved 9 October 2025. 
  7. ↑ "Pharmacologic Activity of Substituted Tryptamines at 5-Hydroxytryptamine (5-HT)2A Receptor (5-HT2AR), 5-HT2CR, 5-HT1AR, and Serotonin Transporter". The Journal of Pharmacology and Experimental Therapeutics 385 (1): 62–75. April 2023. doi:10.1124/jpet.122.001454. PMID 36669875. 
  8. ↑ "Pharmacologic Activity of Substituted Tryptamines at 5-Hydroxytryptamine (5-HT)2A Receptor (5-HT2AR), 5-HT2CR, 5-HT1AR, and Serotonin Transporter". The Journal of Pharmacology and Experimental Therapeutics 385 (1): 62–75. April 2023. doi:10.1124/jpet.122.001454. PMID 36669875. 
  9. ↑ "Convention on Psychotropic Substances, 1971". https://www.unodc.org/unodc/en/commissions/CND/conventions.html. 
  10. ↑ "Controlled Drugs and Substances Act". 5 December 2025. https://laws-lois.justice.gc.ca/eng/acts/c-38.8/FullText.html. 
  11. ↑ "§1308.11 Schedule I.". http://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_11.htm. 
  12. ↑ Erowid Analog Law Vault : Federal Controlled Substance Analogue Act Summary



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