Trimethoxyamphetamine (TMA or TMA-1), also known as 3,4,5-trimethoxyamphetamine (3,4,5-TMA), α-methylmescaline, or mescalamphetamine, is a psychedelic drug of the phenethylamine and amphetamine families.

[1][3] For comparison, mescaline is typically used at doses of 200 to 500 mg and is said to have a duration of 10 to 12 hours or longer.

[7] In contrast, it is inactive as a releasing agent and reuptake inhibitor of dopamine and norepinephrine (EC50 > 100,000 nM).

[7] Despite its apparent SRA activity in vitro, TMA did not increase brain serotonin or dopamine levels in rodents in vivo.

[9][8] The low potency of TMA as a serotonin 5-HT2A receptor agonist is analogous to the case of mescaline, which is a well-known and widely used psychedelic but is likewise a very low-potency agonist of this receptor, showing an affinity (Ki) of 9,400 nM, an EC50 of 10,000 nM, and an Emax of 56% in the same study.