4-HO-DPT is officially known as 4-hydroxy dipropyltryptamine, and occasionally referred to as Procin. 4-HO-DPT is a psychedelic substance of the tryptamine class. 4-HO-DPT is first synthesized by Alexander Shulgin and documented in his book TiHKAL (Tryptamines I Have Known and Loved). Researchers use it as an entheogenic compound. In comparison to other tryptamines such as 4-HO-DMT and 4-AcO-DMT, 4-hydroxy dipropyltryptamine is very similar in outcomes.