2C-T-9 is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin, sometimes used as an entheogen.

2C-T-9 is 2,5-dimethoxy-4-(n)-butylthiophenethylamine.

The IUPAC name of 2C-T-9 is 1-(4-(n-butylthio)-2,5-dimethoxyphenyl)-2-aminoethane.

In his book PiHKAL (Phenethylamines i Have Known And Loved), Shulgin lists the dosage range as 60 - 100 mg.

It is generally taken orally, and effects typically last 12 to 18 hours. There have been no reported deaths from 2C-T-9. The drug is said to taste like motor oil, and experiences have focused primarily on energy as opposed to creativity or insight.

The mechanism that produces 2C-T-9’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT_2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.

The toxicity of 2C-T-9 is not well documented. 2C-T-9 is considerably less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other hard drugs such as alcohol, ecstasy or cocaine.