2C-D

2C-D, also known as 4-methyl-2,5-dimethoxyphenethylamine, is a psychedelic drug of the phenethylamine and 2C families. It has an unusually wide and gradual dose range and at low doses produces claimed cognitive enhancer-like effects, mild stimulant effects, and mild perceptual effects, whereas at high doses, it produces robust psychedelic effects. The drug is taken orally.

It acts as an agonist of the serotonin 5-HT2 receptors, including of the serotonin 5-HT2A receptor. The drug is structurally related to other psychedelic and related phenethylamines such as its higher homologues DOM and Ariadne (4C-D) and other 2C psychedelics like 2C-B and 2C-E.

2C-D was first described in the literature by Beng T. Ho and colleagues in 1970. Its properties and effects in humans were described by Alexander Shulgin and colleagues in 1975. The drug was extensively studied by Hanscarl Leuner under the names DMM-PEA and LE-25 in psychedelic-assisted psychotherapy in Germany in the 1970s and 1980s. It was also informally studied by Darrell Lemaire as a potential "smart drug" in the 1970s and 1980s. 2C-D was first encountered as a novel designer drug by 2005. It became a controlled substance in the United States in 2012.