Tetrahydroharmine

Tetrahydroharmine (THH) is a fluorescent indole alkaloid that occurs in the tropical liana species Banisteriopsis caapi. THH weakly inhibits serotonin reuptake.

Two other harmala alkaloids in B. caapi, harmaline and harmine, are reversible inhibitors of monoamine oxidase A. Tetrahydroharmine, however, does not inhibit monoamine oxidase B.