This is the fumarate-salt. 4-HO-MET is chemically similar to Psilocin and described as a more recreational version of it. It binds to the 5-HT2A receptor with a Ki of 57nM, and the 5-HT2C receptor with a Ki of 141nM. It is also a serotonin-reuptake-inhibitor with a Ki of 200nM and acts as a direct dopamine agonist.
4-HO-MET was first synthesized by Alexander Shulgin and published in 1997 in his book TiHKAL (‘Tryptamines I Have Known and Loved’). Reports of its use in humans appeared in the late 2000s after it had appeared on the market for online research chemicals.