Methyl-TMA, or N-methyl-TMA, also known as N-methyl-3,4,5-trimethoxyamphetamine, is a psychedelic drug of the phenethylamine, amphetamine, and 3C families. It is the N-methyl derivative of 3,4,5-trimethoxyamphetamine (TMA) as well as the ñ,N-dimethyl derivative of mescaline (3,4,5-trimethoxyphenethylamine).
N-Methylation of psychedelic phenethylamines has invariably greatly reduced or eliminated their hallucinogenic activity. Examples of this include related compounds like Beatrice (N-methyl-DOM) and methyl-DOB (N-methyl-DOB), which at assessed doses appear to be inactive as psychedelics in humans. According to Alexander Shulgin in his book PiHKAL (Phenethylamines I Have Known and Loved) however, methyl-TMA showed "some mental disturbances" at the highest assessed dose of 240mg orally. For comparison, the active dose range of TMA is 100 to 250mg orally.
Methyl-TMA was first described in the scientific literature by at least 1984. It was subsequently described further by Shulgin in PiHKAL in 1991.
Methyl-TMA is a controlled substance in Canada under phenethylamine blanket-ban language.