2C-MMDA-3a, also known as 2C-3a, MMDPEA-3a, or 2-methoxy-3,4-methylenedioxyphenethylamine (2-methoxy-MDPEA), is a psychoactive drug of the phenethylamine and MDxx families related to 3,4-methylenedioxyphenethylamine (MDPEA). It is the phenethylamine (2C) analogue of MMDA-3a and the 2-methoxy derivative of MDPEA. According to Alexander Shulgin in his 1991 book PiHKAL (Phenethylamines I Have Known and Loved), 2C-MMDA-3a has a dose range of 40 to 120mg orally with marginal effects. At 40mg, there was perhaps the hint of a psychic energizer (antidepressant); at 65mg, there was pleasant mood elevation; and at 80 and 120mg, there was brief parasthesia. Shulgin has noted the modest change in effects with the drug over a three-fold dose range and has wondered whether it might be useful as an antidepressant or might be a serotonin reuptake inhibitor. The chemical synthesis of 2C-MMDA-3a has been described. It was first described in the scientific literature by Shulgin and colleagues by 1969.