4C-TFM, also known as TFM-Ariadne or 4C-DOTFM, as well as 4-trifluoromethyl-2,5-dimethoxy-ñ-ethylphenethylamine, is a serotonin 5-HT<sub>2</sub> receptor agonist of the phenethylamine, phenylisobutylamine, and 4C families related to Ariadne (4C-D). It is a close analogue of the psychedelic drugs 2C-TFM and DOTFM, with 2C-TFM having no substitution at the ñ carbon, DOTFM having an ñ-methyl group, and 4C-TFM having an ñ-ethyl group. The drug is a potent agonist of the serotonin 5-HT<sub>2A</sub>, 5-HT<sub>2B</sub>, and 5-HT<sub>2C</sub> receptors. It shows similar efficacy as an agonist of these receptors as Ariadne, but shows about 6.4-fold higher potency as a serotonin 5-HT<sub>2A</sub> receptor agonist in comparison. Like Ariadne, 4C-TFM produces an attenuated head-twitch response relative to the psychedelic drug DOPR, with a similar maximal response as Ariadne. The chemical synthesis of 4C-TFM has been described. 4C-TFM was first described in the scientific literature by Michael Cunningham and colleagues in 2023.