2,5-Dimethoxy-4-propylamphetamine

Use and effects

In his book PiHKAL (Phenethylamines I Have Known and Loved), Alexander Shulgin lists DOPR's dose as 2.5 to 5mg orally and its duration as 20 to 30hours. It is said to have a very slow onset. The effects of DOPR have been reported to include closed-eye imagery, visuals, thinking changes, and insomnia and sleep disruption, among others. In one of the reports, it was described as a "heavy duty psychedelic", including strong and unignorable visuals.

Interactions

Pharmacology

Pharmacodynamics

DOPR acts as an agonist of the serotonin 5-HT2 receptors, including of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors. It has very weak affinity for the serotonin 5-HT1 receptor. The drug has also been assessed at other receptors.

It produces the head-twitch response (HTR), a behavioral proxy of psychedelic effects, in rodents. It is slightly more potent but slightly less efficacious than DOM in producing the head-twitch response. As with many other psychedelics, DOPR shows an inverted U-shaped dose–response curve in terms of the HTR, increasing it at lower doses and having diminished effectiveness at higher doses.

DOPR showed no significant effects on locomotor activity in rodents at the assessed doses, but showed a trend towards hyperlocomotion at the highest dose. In a subsequent study however, it produced hyperlocomotion at lower doses and hypolocomotion at higher doses. The drug has shown pro-motivational effects in rodents at sub-hallucinogenic doses or so-called "microdoses". DOPR's close analogue DOET has also been clinically studied at sub-hallucinogenic doses as a "psychic energizer". DOPR produces antidepressant-like effects in rodents.

At higher doses, DOPR produces hypothermia in rodents.

Pharmacokinetics

DOPR crosses the blood–brain barrier in rodents. The drug showed the highest brain/plasma ratio among DOM homologues in rodents, whereas 2,5-dimethoxyamphetamine (2,5-DMA) showed the lowest. This was involved in potency differences between the drugs.

Chemistry

Synthesis

The chemical synthesis of DOPR has been described.

Analogues

Analogues of DOPR include DOM, DOET, DOiP, DOBU, DOAM, DOPF, 2C-P, and 4C-P, among others.

History

DOPR was first described in the literature by Alexander Shulgin in 1970. Subsequently, it was described in greater detail by Shulgin in his 1991 book PiHKAL (Phenethylamines I Have Known and Loved).

Society and culture

Legal status

Canada

DOPR is a controlled substance in Canada under phenethylamine blanket-ban language.

United States

DOPR is not an explicitly controlled substance in the United States. However, it could be considered a controlled substance under the Federal Analogue Act if intended for human consumption.

References

References

1. (September 1991). "PiHKAL: A Chemical Love Story". Transform Press.
2. (November 2025). "The 4-alkyl chain length of 2,5-dimethoxyamphetamines differentially affects in vitro serotonin receptor actions versus in vivo psychedelic-like effects". Mol Psychiatry.
3. (14 July 1969). "phenethylamines and their pharmacologically-acceptable salts".
4. (February 2025). "Low (micro)doses of 2,5-dimethoxy-4-propylamphetamine (DOPR) increase effortful motivation in low-performing mice". Neuropharmacology.
5. (December 2022). "ACNP 61st Annual Meeting: Poster Abstracts P541 - P809: P572. 2,5-Dimethoxy-4-Propylamphetamine (DOPR) Increased Effortful Motivation in Mice". Neuropsychopharmacology.
6. (January 2023). "Pharmacological Mechanism of the Non-hallucinogenic 5-HT_2A Agonist Ariadne and Analogs". ACS Chemical Neuroscience.
7. (2023). "Binding and functional structure-activity similarities of 4-substituted 2,5-dimethoxyphenyl isopropylamine analogues at 5-HT_2A and 5-HT_2B serotonin receptors". Frontiers in Pharmacology.
8. (January 1987). "Central serotonin receptors as targets for drug research". J Med Chem.
9. (1 October 2023). "Learning about STP: A Forgotten Psychedelic from the Summer of Love". History of Pharmacy and Pharmaceuticals.
10. (1978). "Stimulants". Springer US.
11. (September 1968). "DOM (STP), a new hallucinogenic drug, and DOET: effects in normal subjects". Am J Psychiatry.
12. (July 1969). "A new psychotropic agent. Psychological and physiological effects of 2,5-dimethoxy-4-ethyl amphetamine (DOET) in man". Arch Gen Psychiatry.
13. (January 1971). "DOET (2,5-dimethoxy-4-ethylamphetamine), a new psychotropic drug. Effects of varying doses in man". Arch Gen Psychiatry.
14. (July 1974). "Stereospecific actions of DOET (2,5-dimethoxy-4-ethylamphetamine) in man". Arch Gen Psychiatry.
15. (2026). "ACNP 64th Annual Meeting: Poster Abstracts P584-P872: The psychedelic DOPR improves depression-related behavior in mice". Neuropsychopharmacology.
16. "Controlled Drugs and Substances Act".
17. (January 2026). "Orange Book: List of Controlled Substances and Regulated Chemicals (January 2026)". U.S. [[Department of Justice]]: [[Drug Enforcement Administration]] (DEA): Diversion Control Division.