6-Methoxyharman, also known as isoharmine, is a ò-carboline and harmala alkaloid. It is an analogue of other ò-carbolines like harman and 6-methoxyharmalan. The compound has been found to be naturally occurring in Peganum harmala and Virola species such as Virola cuspidata and Virola elongata. It is a potent monoamine oxidase inhibitor (MAOI). In addition, 6-methoxyharman has been found to bind to serotonin receptors, including the serotonin 5-HT<sub>2C</sub> receptor (K<sub>i</sub> = 3,700nM), but notably not to the serotonin 5-HT<sub>2A</sub> or 5-HT<sub>1A</sub> receptors (K<sub>i</sub> = >10,000). It may potentiate the effects of psychedelic tryptamines like dimethyltryptamine (DMT) via its MAOI activity, for instance when they are used as Virola-containing hallucinogenic snuffs. According to Alexander Shulgin, Claudio Naranjo might have tested the effects 6-methoxyharman in humans, but this is unclear.