3-Thiosymbescaline (3-TSB), also known as 3-ethylthio-4-methoxy-5-ethoxyphenethylamine, is a chemical compound of the phenethylamine and scaline families related to mescaline. It is the analogue of symbescaline in which the ethoxy group at the 3 position has been replaced with an ethylthio group. The compound is one of two possible thiosymbescaline (TSB) positional isomers, the other being 4-thiosymbescaline (4-TSB).
In his book PiHKAL (Phenethylamines I Have Known and Loved) and other publications, Alexander Shulgin lists 3-TSB's dose as greater than 200mg orally and its duration as unknown. The compound produced no effects whatsoever at a dose of up to 200mg orally.
The chemical synthesis of 3-TSB has been described.
3-TSB was first described in the scientific literature by Shulgin and Peyton Jacob III in 1984. Subsequently, it was described in greater detail by Shulgin in PiHKAL in 1991.