Shirt a Phobia

Sample Page

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

See also: Psychedelic drug § Interactions, and Trip killer § Serotonergic psychedelic antidotes

Pharmacology

Pharmacodynamics

4-HO-MPT activities
Target Affinity (Ki, nM)
5-HT1A 106–910 (Ki)
490 (EC50Tooltip half-maximal effective concentration)
90% (EmaxTooltip maximal efficacy)
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
SERTTooltip Serotonin transporter 910–1,180 (Ki)
575 (IC50Tooltip half-maximal inhibitory concentration)
DATTooltip Dopamine transporter IA
Notes: The smaller the value, the more avidly the drug binds to the site. Footnotes: a = Stimulation of IP1Tooltip inositol phosphate formation. Sources: [3][4][7]

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.[7]

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.[8]

Canada

4-HO-MPT is not an explicitly nor implicitly controlled substance in Canada as of 2025.[9]

United States

4-HO-MPT is not scheduled at the federal level in the United States,[10] 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.[11]

See also

References

  1. ^ a b c d e f g h i 4-HO-MPT Entry in TIHKAL @ Erowid.org
  2. ^ a b c d e f g Halberstadt AL, Chatha M, Klein AK, Wallach J, Brandt SD (May 2020). “Correlation between the potency of hallucinogens in the mouse head-twitch response assay and their behavioral and subjective effects in other species” (PDF). Neuropharmacology. 167 107933. doi:10.1016/j.neuropharm.2019.107933. PMC 9191653. PMID 31917152. Table 4 Human potency data for selected hallucinogens. […]
  3. ^ a b c d e f g Klein AK, Chatha M, Laskowski LJ, Anderson EI, Brandt SD, Chapman SJ, et al. (April 2021). “Investigation of the Structure-Activity Relationships of Psilocybin Analogues”. ACS Pharmacology & Translational Science. 4 (2): 533–542. doi:10.1021/acsptsci.0c00176. PMC 8033608. PMID 33860183.
  4. ^ a b c d Glatfelter GC, Naeem M, Pham DN, Golen JA, Chadeayne AR, Manke DR, et al. (April 2023). “Receptor Binding Profiles for Tryptamine Psychedelics and Effects of 4-Propionoxy-N,N-dimethyltryptamine in Mice”. ACS Pharmacology & Translational Science. 6 (4): 567–577. doi:10.1021/acsptsci.2c00222. PMC 10111620. PMID 37082754.
  5. ^ a b Repke DB, Ferguson WJ, Bates DK (1981). “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. doi:10.1002/jhet.5570180131. ISSN 0022-152X. Retrieved 9 October 2025.
  6. ^ a b Tanaka R, Kawamura M, Hakamatsuka T, Kikura-Hanajiri R (2021). “Identification of six tryptamine derivatives as designer drugs in illegal products”. Forensic Toxicology. 39 (1): 248–258. doi:10.1007/s11419-020-00556-5. ISSN 1860-8965. Retrieved 9 October 2025.
  7. ^ a b c Kozell LB, Eshleman AJ, Swanson TL, Bloom SH, Wolfrum KM, Schmachtenberg JL, et al. (April 2023). “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. doi:10.1124/jpet.122.001454. PMC 10029822. PMID 36669875.
  8. ^ “Convention on Psychotropic Substances, 1971”. Archived from the original on 2022-01-19. Retrieved 2016-06-10.
  9. ^ “Controlled Drugs and Substances Act”. Department of Justice Canada. 5 December 2025. Retrieved 20 January 2026.
  10. ^ “§1308.11 Schedule I.” Archived from the original on 2009-08-27. Retrieved 2016-06-10.
  11. ^ Erowid Analog Law Vault : Federal Controlled Substance Analogue Act Summary