7-Hydroxymitragynine

7-Hydroxymitragynine (7-OH-MIT, often simply referred to as 7-OH) is a terpenoid indole alkaloid present in the plant Mitragyna speciosa (the leaves of which are commonly known as kratom). It was first described in 1994. In humans, it is produced as an active metabolite of mitragynine via hepatic oxidation.

7-OH exhibits greater binding affinity to μ-opioid receptors (MOR) than mitragynine. It acts primarily as a partial agonist at μ-opioid receptors while antagonizing δ- and κ-opioid receptors; unlike traditional opioids, it appears not to recruit the β-arrestin pathway, which may influence its side effect profile.

Recreational use has increased in the United States, often in concentrated retail products. 7-OH occurs only in very small amounts in natural kratom leaves (<2% of total alkaloids), so most commercial material is produced semisynthetically through oxidation of mitragynine. In animal studies, the compound has shown strong analgesic potency (reported up to ~13× that of morphine) and produces opioid-like tolerance and withdrawal. Reports to poison control have risen substantially, and in 2025 the U.S. Food and Drug Administration recommended that it be scheduled; it is not approved for any medical or dietary supplement use.

It is being studied as a potential template for developing opioids with improved safety profiles.