3,4,5-Trimethoxytranylcypromine (TMT), also known as MCPA as well as trans-2-(3,4,5-trimethoxyphenyl)cyclopropylamine, is a possible psychedelic drug of the phenethylamine, scaline, and phenylcyclopropylamine families related to mescaline (3,4,5-trimethoxyphenethylamine). "The placement of the methyl group between the two carbons (so to speak) produces a cyclopropyl system. The simplest example is 2-phenylcyclopropylamine, a drug with the generic name of tranylcypromine and the trade name Parnate. It is a monoamine oxidase inhibitor and has been marketed as an antidepressant, but the compound is also a mild stimulant causing insomnia, restlessness and photophobia. Substitutions on the benzene ring of this system have not been too promising. The DOM analogue, 2,5-dimethoxy-4-methyltranylcypromine is active in man, and is discussed in its own recipe under DMCPA. The inactive mescaline analogue TMT is also mentioned there." [...] "This compound, DMCPA, was modeled directly after the structure of DOM, with the 2,5-dimethoxy-4-methyl substitution pattern. Another analogue of tranylcypromine, similarly modeled, is 3,4,5-trimethoxytranylcypromine, or trans-2-(3,4,5-trimethoxyphenyl)cyclopropylamine (TMT). It has been evaluated at levels of only 13 milligrams orally, and at this dose there were no hints of central activity." It is a cyclized phenethylamine and the analogue of mescaline in which the α and β positions of the ethyl side chain have been cyclized to form a cyclopropane ring. The drug may also be thought of as a structural hybrid between mescaline and the antidepressant tranylcypromine.
Use and effects In his book PiHKAL (Phenethylamines I Have Known and Loved), Alexander Shulgin reported that TMT produced no central effects at a dose of 13mg orally. Higher doses were not assessed.
Pharmacology TMT has been reported to produce mescaline-like effects in animals with similar or slightly greater potency than mescaline but a slightly shorter duration. TMT is the trans isomer of a pair of cis and trans isomers, and it is specifically the trans isomer that is active.
History TMT was first described in the scientific literature by G. C. Walters and P. D. Cooper in 1968. Alexander Shulgin subsequently described evaluating a low dose of TMT in humans in his 1991 book PiHKAL (Phenethylamines I Have Known and Loved). TMT was one of the earliest psychedelic-related cyclized phenethylamines to be evaluated. Subsequently, the much more potent 2,5-dimethoxy-4-methylphenylcyclopropylamine (DMCPA) was developed.
Society and culture Legal status Canada TMT is not a controlled substance in Canada as of 2025.
See also Substituted methoxyphenethylamine Cyclized phenethylamine Phenylcyclopropylamine Scaline 2,5-Dimethoxy-4-methylphenylcyclopropylamine (DMCPA)
References
External links MCPA - Isomer Design