4-HO-EPT
Width200px
Width 2225px
Routes of administrationOral
ClassNon-selective serotonin receptor agonist; Serotonin 5-HT2A receptor agonist; Serotonergic psychedelic; Hallucinogen
Atc prefixNone
Cas number2595431-59-5
Pubchem138454310
Chemspiderid129433801
UniiY3J8M5UX6G
Synonyms4-OH-EPT; 4-Hydroxy-N-ethyl-N-propyltryptamine; Eprocin
Iupac name3-{2-[ethyl(propyl)amino]ethyl}-1H-indol-4-ol
C15
H22
N2
O1
SmilesCCCN(CC)CCC1=CNC2=CC=CC(O)=C12
Stdinchi1S/C15H22N2O/c1-3-9-17(4-2)10-8-12-11-16-13-6-5-7-14(18)15(12)13/h5-7,11,16,18H,3-4,8-10H2,1-2H3
StdinchikeyJQELEPKHBXEAHR-UHFFFAOYSA-N

4-HO-EPT, also known as 4-hydroxy-N-ethyl-N-propyltryptamine or as eprocin, is a psychedelic drug of the tryptamine family, which is structurally related to psilocin (4-HO-DMT).[1] It was encountered as a novel designer drug in Japan by 2021.[1]

Use and effects

4-HO-EPT was not included nor mentioned in Alexander Shulgin's book TiHKAL (Tryptamines I Have Known and Loved).[2] Subsequently, however, an assumed prodrug of 4-HO-EPT, 4-AcO-EPT, has emerged as a novel designer drug, and has been said based on online anecdotal reports to have a dose of 20 to 30 mg orally.[3][4]

Interactions

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

Pharmacology

Pharmacodynamics

4-HO-EPT activities
TargetAffinity (Ki, nM)
5-HT1A163
5-HT1B1,097
5-HT1D644
5-HT1E591
5-HT2A546 (Ki)
3.2 (EC50)
100% (Emax)
5-HT2B62 (Ki)
4.3 (EC50)
89% (Emax)
5-HT2C1,272 (Ki)
129 (EC50)
89% (Emax)
5-HT5A1,576
5-HT6284
5-HT7438
α2A2,073
α2B, α2C>10,000
D23,010
D3985
D4, D5>10,000
H1406
H2>10,000
M4>10,000
σ11,400
σ21,773
KOR>10,000
NR2B5,947
SERT1,257
DAT>10,000
Notes: The smaller the value, the more avidly the drug interacts with the site. Sources: [5][6]

4-HO-EPT is a potent full agonist of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors.[5][6] It has one to two orders of magnitude greater potency as a serotonin 5-HT2A and 5-HT2B receptor agonist than as a serotonin 5-HT2C receptor agonist.[5] The drug also shows affinity for other serotonin receptors, such as the serotonin 5-HT1A and 5-HT6 receptors.[6] 4-HO-EPT produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents.[5]

Pharmacokinetics

The metabolism of 4-HO-EPT has been studied.[7]

Chemistry

Analogues

Analogues of 4-HO-EPT include ethylpropyltryptamine (EPT), 5-MeO-EPT, 5-fluoro-EPT, 4-HO-MPT, 4-HO-PiPT, 4-HO-DET, and 4-HO-DPT, among others.

Society and culture

Canada

4-HO-EPT is not a controlled substance in Canada as of 2025.[8]

United Kingdom

4-HO-EPT is illegal in the United Kingdom as a result of the Psychoactive Substances Act of 2016.[9]

United States

4-HO-EPT may be considered an analogue of psilocin, which is a Schedule I drug under the Controlled Substances Act. As such, the sale for human consumption would be illegal under the Federal Analogue Act.[citation needed]

See also

References

  1. ^ 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.
  2. ^
  3. ^ "4-OH-EPT AC (4-AcO-EPT)" (in Russian). АИПСИН. Retrieved 2 January 2026.
  4. ^ "4-HO-EPT AC (4-AcO-EPT)" (in Russian). АИПСИН. Retrieved 2 January 2026.
  5. ^ Klein AK, Chatha M, Laskowski LJ, Anderson EI, Brandt SD, Chapman SJ, McCorvy JD, Halberstadt 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
  6. ^ Glatfelter GC, Naeem M, Pham DN, Golen JA, Chadeayne AR, Manke DR, Baumann MH (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
  7. ^ Bergh MS, Bogen IL, Grafinger KE, Huestis MA, Øiestad ÅM (December 2024). "Metabolite markers for three synthetic tryptamines N-ethyl-N-propyltryptamine, 4-hydroxy-N-ethyl-N-propyltryptamine, and 5-methoxy-N-ethyl-N-propyltryptamine". Drug Testing and Analysis. 16 (12): 1544–1557. doi:10.1002/dta.3668. PMC 11635065. PMID 38459837
  8. ^ "Controlled Drugs and Substances Act". Department of Justice Canada. Retrieved 19 January 2026.
  9. ^ "Misuse of Drugs Act 1971 (Legislation.gov.uk)"