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Other names | 7-OH; 7α-Hydroxy-7H-mitragynine; [1] 9-Methoxycorynantheidine hydroxyindolenine [1] |
Dependence liability | Moderate |
Addiction liability | Moderate [2] |
Routes of administration | Oral |
Drug class | Opioid |
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Pharmacokinetic data | |
Metabolites | Mitragynine pseudoindoxyl |
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Chemical and physical data | |
Formula | C23H30N2O5 |
Molar mass | 414.502 g·mol−1 |
3D model (JSmol) | |
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7-Hydroxymitragynine (7-OH-MIT, often simply referred to as 7-OH) is a terpenoid indole alkaloid present in the plant Mitragyna speciosa , commonly known as kratom. [3] It was first described in 1994. [4] In humans, it is produced as an active metabolite of mitragynine via hepatic oxidation. [5] 7-OH exhibits greater binding affinity to μ-opioid receptors (MOR) than mitragynine.[ citation needed ]
Frequent consumption of 7-OH is known to cause dependence, addiction, and—upon cessation of use—withdrawal symptoms similar to those caused by most opiates and opioids.[ citation needed ]
7-OH-MIT, like mitragynine, appears to be a mixed opioid receptor agonist/antagonist, with recent research indicating that it acts as a partial agonist at μ-opioid receptors and as a competitive antagonist at δ- and κ-opioid receptors. [6] [7] Both 7-OH-MIT and mitragynine do not appear to activate the β-arrestin pathway, distinguishing it from traditional opiate and opioid chemicals. [6] A study has found the binding affinity of 7-OH-MIT to be μ-opioid receptor (MOR) 37 (± 4) nM and δ-opioid receptor (DOR) 91 (± 8) nM and κ-opioid receptor (KOR) 132 (± 7) nM. [8] Another study found the binding affinity of 7-OH-MIT to be MOR 16 (± 1) nM and DOR 137 (± 21) nM and KOR 133 (± 37) nM. [9] Another study found the binding affinity of 7-OH-MIT to be MOR 13.5 nM, DOR 155 nM, and KOR 123 nM. [9] Cross-tolerance to morphine was evident in mice rendered tolerant to 7-hydroxymitragynine and vice versa. Naloxone-induced withdrawal signs were elicited equally in mice chronically treated with 7-hydroxymitragynine or morphine. [10]
In natural kratom leaves, 7-hydroxymitragynine is only present in small amounts, comprising less than 2% of overall alkaloid content. [11] Therefore, extracting 7-OH-MIT in high concentrations directly from natural kratom leaves is not practical. Instead, 7-hydroxymitragynine can be produced semisynthetically via the oxidation of mitragynine. [5]
7-OH has been rising in popularity as a recreational drug, particularly in the United States. Its ability to bind to opioid receptors can cause addictive effects. In an electrical stimulation test using guinea-pig ileum, 7-OH performed 13 times greater pain relief than that of morphine. [12] The drug's novelty has meant that it has increasingly been sold unregulated over the counter in gas stations and smoke shops, often in highly concentrated "candy-like" or pill form alongside kratom powder and other supplements with little to no information provided to consumers about its effects. [11]
According to the United States Poison Control Center, the number of cases relating to kratom-based products such as 7-OH have increased from under 200 in 2014 to 1600 in 2024, with approximately 40% of 7-OH reports coming from individuals who were abusing the drug. [13]
In July 2025, the US Food and Drug Administration (FDA) formally recommended that the Drug Enforcement Administration (DEA) classify 7-hydroxymitragynine as a controlled substance. [14] Despite claims by 7-OH products that they can be used to treat anxiety and pain, the drug is not approved by the FDA for any medical use or as a food supplement. [15]
On August 13, 2025, Florida attorney general James Uthmeier announced an emergency rule placing 7-hydroxymitragynine into schedule I status under Florida state law. [16] [17] [18]
Studies on 7-hydroxymitragynines safety have been unable to identify an LD50 orally with no deaths occurring. [19] 7-hydroxymitragynine has been described as a "prototypical" compound to develop a new generation of opioids with a better safety profile. [20]
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: CS1 maint: bibcode (link)7-OH is a naturally occurring substance in the kratom plant (Mitragyna speciosa), but only a minor constituent that comprises less than 2% of the total alkaloid content in natural kratom leaves.
7-OH displayed approximately 13-fold greater potency than morphine