7-Hydroxymitragynine

7-Hydroxymitragynine at a Glance

7-Hydroxymitragynine — almost always shortened to 7-OH — is a minor indole alkaloid of kratom (Mitragyna speciosa) and, simultaneously, the oxidation metabolite of mitragynine formed by cytochrome P450 3A ^{5,11Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}. In the leaf it is a trace component: under 2% of the total alkaloid fraction, averaging roughly 0.02–0.04% of leaf alkaloid extract, and in several studies detectable only in particular cultivars and seasons ^{15,30Reference 15Zhang M et al. · 2025Alkaloid biosynthesis in medicinal crop kratom (Mitragyna speciosa) varies with postharvest, genetic, and seasonal factorsView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Mitragynine, by contrast, makes up the bulk of the alkaloid fraction.

Despite that scarcity, 7-OH is the kratom alkaloid with conventional opioid pharmacology. It is a substantially more efficacious µ-opioid receptor agonist than mitragynine ^{3,4Reference 3Kruegel AC et al. · 2016Synthetic and Receptor Signaling Explorations of the Mitragyna Alkaloids: Mitragynine as an Atypical Molecular Framework for Opioid Receptor ModulatorsView study →Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →}, it is self-administered by rats where mitragynine is not ^{9Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →}, it produces dose-dependent respiratory depression more potent than morphine in rodents ^{8Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →}, and human case reports describe physical dependence requiring medically managed withdrawal ^{27,28Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →}. Two things follow. First, there is a serious argument — contested, and set out below — that 7-OH formed in vivo is what actually delivers kratom’s opioid effect, effectively making mitragynine a prodrug. Second, isolating or enriching 7-OH strips away every attenuating feature of the whole leaf.

This page is a scholarly pharmacology, toxicology, forensic and regulatory reference. It gives no dose for effect and no preparation, extraction, enrichment or synthesis guidance. It states the harms plainly, because they are the dominant clinical facts about this molecule, and it reports the legal status as of July 2026 with the dates the claims were checked.

Metabolite or Constituent?

7-OH occupies an unusual position: it is genuinely both a natural leaf alkaloid and a mammalian metabolite of mitragynine, and the literature disagrees about which of those matters more.

The case for “constituent.” 7-OH was first isolated from the plant, not from plasma — Ponglux and colleagues described it in 1994 as a new indole alkaloid of Thai M. speciosa leaf ^{1Reference 1Ponglux D et al. · 1994A New Indole Alkaloid, 7 alpha-Hydroxy-7H-mitragynine, from Mitragyna speciosa in ThailandView study →}, and León and colleagues subsequently isolated it from US-grown leaf alongside mitragynine, paynantheine, corynantheidine and the oxindoles ^{16Reference 16León F et al. · 2009Phytochemical characterization of the leaves of Mitragyna speciosa grown in U.S.AView study →}. It is measurable in leaf and leaf extracts by validated chromatography, and it partitions unevenly within the plant: one 2026 quantitative study detected 7-OH only in leaves, never in shoots, and found southern-Thai material higher in 7-OH than northern ^{17Reference 17Krongrawa W et al. · 2026Effects of Botanical Variation, Plant Part, and Extraction Technique on Mitragynine and 7-Hydroxymitragynine in Kratom (Mitragyna speciosa) Extracts Quantified by a Validated HPLC-DAD MethodView study →}.

The case for “artefact of handling.” The amounts are tiny and unstable. Post-harvest work found 7-OH averaging only 0.02–0.04% of leaf alkaloid extract and present only in specific seasons, varying by cultivar — a genotype-by-environment pattern rather than a reliable constitutive one ^{15Reference 15Zhang M et al. · 2025Alkaloid biosynthesis in medicinal crop kratom (Mitragyna speciosa) varies with postharvest, genetic, and seasonal factorsView study →}. Marketplace and analytical surveys describe 7-OH as at trace levels or effectively undetectable in fresh leaf ^{20,22Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →}. A German-language review makes the sharpest version of the point: dried leaf, the form typically consumed in Western countries, carries higher 7-OH than the fresh leaf chewed in Southeast Asia — implicating drying and storage in its appearance ^{19Reference 19Gahr M · 2023ReviewKratom (Mitragyna Speciosa): a Psychoactive Plant with Opportunities and RisksView study →}. 7-OH is also chemically fragile, degrading in stored biological matrix within weeks and, under simulated gastric conditions, converting to the byproduct 3-dehydromitragynine ^{23,25Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →Reference 25Osawa KA · 2025Postmortem distribution of mitragynine and 7-hydroxymitragynine in 51 casesView study →}.

The case for “the real actor.” Kruegel and colleagues showed in 2019 that mitragynine is converted to 7-OH by CYP3A isoforms in both mouse and human liver preparations, that 7-OH is formed in mice after mitragynine dosing, and that brain concentrations of the metabolite were sufficient to explain most or all of mitragynine’s opioid-receptor-mediated analgesia — while mitragynine itself reached brain levels far above its own binding affinity without appearing to activate the receptor directly ^{5Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →}. That is the prodrug reading, and it was corroborated in humans in 2024: pretreatment with the CYP3A4 inhibitor itraconazole cut 7-OH exposure by 56% (C_max) and 43% (AUC) after a kratom tea dose, the first direct human evidence of the conversion ^{11Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}.

The case against. Berthold and colleagues dosed mitragynine and 7-OH at equianalgesic oral doses in mice and found the opposite: 7-OH alone was only 2.8-fold more potent than mitragynine, and at equivalent effective doses the maximum brain concentration of 7-OH reached as a metabolite was 11-fold lower than when 7-OH was given directly. Their conclusion was that 7-OH has a negligible role in mitragynine’s antinociception in mice ^{6Reference 6Berthold EC et al. · 2022AnimalThe Lack of Contribution of 7-Hydroxymitragynine to the Antinociceptive Effects of Mitragynine in Mice: A Pharmacokinetic and Pharmacodynamic StudyView study →}. Hill and colleagues land between the two: CYP3A inhibition reduced both mitragynine’s antinociception and its respiratory depression, implying a real metabolic contribution, but the rate of conversion is limiting — which is precisely why mitragynine’s respiratory depression plateaus while 7-OH’s does not ^{7Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →}.

Where that leaves it. The disagreement is about how much of whole-leaf kratom’s opioid effect is metabolite-mediated, and it is not settled. What is not in dispute is the asymmetry it creates: taking mitragynine means generating 7-OH slowly, in small amounts, through a saturable enzyme. Taking 7-OH directly bypasses that bottleneck entirely ^{20,22Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →}.

Abuse Liability & Dependence

This is the section that separates 7-OH from the rest of the kratom alkaloids, and it should be stated without hedging.

In the definitive preclinical study, Hemby and colleagues ran both alkaloids through rat self-administration. 7-OH substituted for morphine dose-dependently and was readily self-administered on its own; mitragynine was not. Pretreatment with naloxonazine (a µ1 antagonist) and naltrindole (a δ antagonist) each reduced 7-OH self-administration, while only the µ1 antagonist reduced morphine intake. More striking, prior exposure to 7-OH increased subsequent morphine intake, while prior exposure to mitragynine decreased it. Their conclusion — that mitragynine lacks abuse potential and reduces opioid intake, while 7-OH “should be considered a kratom constituent with high abuse potential” — is the pharmacological basis for treating the two molecules differently ^{9Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →}.

Drug-discrimination work points the same way: in rats trained to discriminate morphine, 7-OH produced 99.7% morphine-appropriate responding, a full substitution, where mitragynine reached only 72.3% ^{4Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →}. Physical dependence follows the same split — a comparative study of natural and semi-synthetic kratom alkaloids found the atypical alkaloids produced less physical dependence than classical opioids, but 7-OH sits at the classical end of that spectrum ^{10Reference 10Wilson LL et al. · 2021Kratom Alkaloids, Natural and Semi-Synthetic, Show Less Physical Dependence and Ameliorate Opioid WithdrawalView study →}.

The human picture has caught up since 2025. Published case reports describe a patient requiring inpatient medically managed withdrawal from high-dose 7-OH ^{27Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →}, a retrospective case series treating 7-OH use with buprenorphine ^{28Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →}, and a case of prolonged immobilisation from a 7-OH product ending in rhabdomyolysis, renal failure and lasting neurological deficits ^{29Reference 29Dorey A et al. · 2026Case reportRhabdomyolysis, renal failure and chronic neurologic deficits after prolonged immobilization from use of a 7-hydroxymitragynine productView study →}. US regulatory surveillance recorded 86 FAERS cases involving 7-OH as of February 2026, 79 of them serious and 9 fatal, with drug dependence and withdrawal syndrome the most common reported events ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

The Concentrated 7-OH Product Market

Since late 2024 a distinct product category has appeared in the US: tablets, sublingual films, gummies, shots and vapes labelled “7-OH” and sold in smoke shops, gas stations and online, frequently marketed as though they were ordinary kratom ^{21,22Reference 21Smith KE et al. · 2025The rise of novel, semi-synthetic 7-hydroxymitragnine productsView study →Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →}. They are not.

A marketplace audit covering September 2024 to February 2025 catalogued 304 semi-synthetic products: 82.2% were 7-OH-only, 14.5% combined 7-OH with mitragynine pseudoindoxyl, and 3.3% were pseudoindoxyl alone. Almost all were marketed under the kratom banner; 73.3% made effect claims and 12.5% made outright drug claims, and several product names alluded to prescription opioids ^{22Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →}. A 2026 chemical analysis of commercial products found that over 98% of 7-OH-labelled products were of semi-synthetic origin — identifiable from over-oxidised byproducts left by the manufacturing route — with substantial mismatches between labelled and measured 7-OH content, and labelled doses spanning 0.001 to 33.6 mg per serving ^{23Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}. The regulatory record puts the spread even wider, at 1 mg to 700 mg per serving or dose across surveyed products ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Three things make this category pharmacologically distinct from leaf kratom, and all three are consequences of the sections above:

• The metabolic bottleneck is gone. Whole leaf delivers mitragynine and generates 7-OH slowly through a saturable CYP3A step; a concentrated product delivers the active molecule directly ^{5,7,20Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →}.
• The competing alkaloids are gone. Leaf material is a mixture, and the co-occurring alkaloids attenuate the effect of any one of them; an isolate does not ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.
• The delivery is faster. Sublingual tablets and films are designed for rapid systemic absorption, and rapid delivery raises abuse potential independent of the molecule ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Analysts have argued from the outset that these should be understood as de facto opioids sold outside the opioid regulatory system ^{22Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →}, and the review literature now describes concentrated 7-OH products as “pharmacologically and toxicologically distinct from kratom leaf” ^{20Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →}. Whole-leaf products, by contrast, look chemically ordinary: the most comprehensive US survey of whole-leaf material (341 samples) found compositions closely matching the expected M. speciosa fingerprint, with no evidence of adulteration with illicit or prescription drugs ^{32Reference 32Sharma A et al. · 2025Chemical Analysis and Alkaloid Intake for Kratom Products Available in the United StatesView study →}.

What It's Used For

7-OH is characterised almost entirely as an isolated molecule in animals and cell systems. There is no controlled human efficacy trial of 7-OH, and its best-established “applications” are a defined opioid pharmacology and a defined set of opioid harms — not a therapy.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume — and here it tracks how well characterised an action is, not an endorsement. None of these rows is a recommended use; two of them are harms.

01Respiratory Depression (Adverse Pharmacology)Promising62%Rodent plethysmography with naloxone reversal, plus human overdose and poison-centre reports ^{7,8,30Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}

02Reinforcement & Abuse LiabilityPromising60%Rat self-administration and drug discrimination; human dependence/withdrawal case reports ^{4,9,27,28Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →}

03Opioid Analgesia (Antinociception)Promising58%Consistent, orally active, naloxone-reversible antinociception in mice and rats; no human trial ^{2,4,6Reference 2Matsumoto K et al. · 2004AnimalAntinociceptive effect of 7-hydroxymitragynine in mice: Discovery of an orally active opioid analgesic from the Thai medicinal herb Mitragyna speciosaView study →Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 6Berthold EC et al. · 2022AnimalThe Lack of Contribution of 7-Hydroxymitragynine to the Antinociceptive Effects of Mitragynine in Mice: A Pharmacokinetic and Pharmacodynamic StudyView study →}

04Contribution to Whole-Leaf Kratom EffectsShaky35%Directly contradictory mouse PK/PD studies; human CYP3A-inhibition data confirm the conversion only ^{5,6,11Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →Reference 6Berthold EC et al. · 2022AnimalThe Lack of Contribution of 7-Hydroxymitragynine to the Antinociceptive Effects of Mitragynine in Mice: A Pharmacokinetic and Pharmacodynamic StudyView study →Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}

How 7-Hydroxymitragynine Works

7-OH is the 7-hydroxyindolenine of mitragynine — mitragynine with a hydroxyl at C-7 and the indole rearranged accordingly. That single oxidation converts an atypical, low-efficacy, multi-target alkaloid into a straightforward µ-opioid agonist.

The load-bearing point is that the oxidation is not a subtle tweak. Mitragynine’s pharmacology is a mixture — low-efficacy µ activity plus adrenergic and other non-opioid actions, one of which appears to be respiratory stimulation ^{8Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →}. 7-OH’s pharmacology is opioid, full stop ^{4,9Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →}.

β-Arrestin, Bias, and Why It Does Not Rescue 7-OH

The kratom alkaloids became famous partly through biased agonism. In the first receptor-level functional characterisation, Kruegel and colleagues reported that both mitragynine and 7-OH are G-protein-biased µ agonists that do not recruit β-arrestin following receptor activation, and proposed the scaffold as a framework for safer opioids ^{3Reference 3Kruegel AC et al. · 2016Synthetic and Receptor Signaling Explorations of the Mitragyna Alkaloids: Mitragynine as an Atypical Molecular Framework for Opioid Receptor ModulatorsView study →}. Váradi and colleagues extended the idea to mitragynine pseudoindoxyl, a µ agonist/δ antagonist that likewise fails to recruit β-arrestin-2 ^{35Reference 35Váradi A et al. · 2016Mitragynine/Corynantheidine Pseudoindoxyls As Opioid Analgesics with Mu Agonism and Delta Antagonism, Which Do Not Recruit β-Arrestin-2View study →}. Because β-arrestin-2 signalling was, at the time, thought to mediate opioid respiratory depression, the inference was that these molecules should be respiratory-sparing.

That inference does not survive contact with the in vivo data on 7-OH. In mice, 7-OH depressed respiration dose-dependently with no ceiling ^{7Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →}; in rats it halved minute volume at 4.5-fold morphine’s potency ^{8Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →}. Whatever its arrestin behaviour, 7-OH depresses breathing like a conventional opioid.

The field has since moved on from the simple version of the hypothesis. The IUPHAR review of opioid efficacy, bias and selectivity concludes that G-protein bias at the µ receptor may not be the route to safer analgesics after all, and that differences previously attributed to bias are often better explained by intrinsic efficacy ^{34Reference 34Ramos-Gonzalez N et al. · 2023ReviewIUPHAR themed review: Opioid efficacy, bias, and selectivityView study →}. Read through that lens, kratom’s comparatively benign whole-leaf respiratory profile is best explained not by bias but by two efficacy/kinetic facts: mitragynine has low µ efficacy, and the conversion to the high-efficacy metabolite is rate-limited ^{4,7Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →}. Remove the rate limit — which is exactly what a concentrated 7-OH product does — and the protection disappears.

Pharmacokinetics

As a metabolite (whole-leaf exposure). The largest human study — a randomised, double-blind, placebo-controlled dose-escalation of encapsulated dried kratom leaf powder — measured both alkaloids by LC-MS/MS after single and 15 daily doses. Median 7-OH T_max was 1.2–1.8 h after a single dose (mitragynine 1.0–1.3 h), 7-OH reached steady state within 7 days, and its mean terminal half-life ran 4.7 h after one dose and 24.7 h after multiple doses — far shorter than mitragynine’s 43.4 h and 67.9 h. Critically, the mean 7-OH : mitragynine concentration ratio was only 0.20–0.31 after a single dose and fell to 0.15–0.21 with repeated dosing ^{12Reference 12Huestis MA et al. · 2024Human Mitragynine and 7-Hydroxymitragynine Pharmacokinetics after Single and Multiple Daily Doses of Oral Encapsulated Dried Kratom Leaf PowderView study →}. Whole-leaf exposure is dominated by mitragynine.

The conversion is CYP3A4-mediated, and demonstrated in humans. Kratom tea containing 23.6 mg mitragynine produced a mitragynine C_max of about 159 ng/mL at 0.84 h and a 7-OH C_max of about 12.8 ng/mL at 1.77 h — 7-OH accounting for roughly 9% of mitragynine’s C_max and 20% of its AUC. Four days of itraconazole 200 mg reduced 7-OH exposure by 56% (C_max) and 43% (AUC) while raising mitragynine C_max 1.5-fold: the first direct human evidence of CYP3A4-mediated conversion ^{11Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}. In liver preparations from both species the same CYP3A dependence holds ^{5Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →}. In rats, dedicated in vitro/in vivo characterisation of 7-OH confirms its disposition as an active metabolite in its own right ^{13Reference 13Chiang YH et al. · 2025In vitroIn Vitro and In Vivo Pharmacokinetic Characterization of 7-Hydroxymitragynine, an Active Metabolite of Mitragynine, in Sprague-Dawley RatsView study →}.

Brain entry is restricted — and this matters. Blood–brain-barrier work found mitragynine had higher blood-to-brain permeability than 7-OH, that 7-OH tends to efflux (ratio ~1.39), that both are P-glycoprotein substrates and inhibitors, and that under 10% of unbound plasma drug crossed the barrier for either. Mitragynine showed 18-fold higher brain-tissue uptake in slice assay; 7-OH’s cellular barrier transport was restricted ^{14Reference 14Yusof SR et al. · 2019Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studiesView study →}. This is part of why the metabolite’s contribution to whole-leaf effects is contested — it is efficacious at the receptor but not efficiently delivered to it.

As an isolate, none of that applies. A concentrated oral or sublingual 7-OH product introduces the high-efficacy molecule directly and, in sublingual form, rapidly — bypassing both the saturable enzymatic step and first-pass metabolism ^{20,30Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. 7-OH is also chemically labile: it degrades to 3-dehydromitragynine under simulated gastric conditions, a byproduct of uncertain toxicity ^{23Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}.

Clinical Trials

There are no clinical trials of 7-hydroxymitragynine as a therapeutic. It has no approved medical use, and as of the 2026 regulatory review there were no investigational new drug applications and no approved new drug applications for it ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Human research involving 7-OH is confined to pharmacokinetic studies where it appears as mitragynine’s metabolite ^{11,12Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →Reference 12Huestis MA et al. · 2024Human Mitragynine and 7-Hydroxymitragynine Pharmacokinetics after Single and Multiple Daily Doses of Oral Encapsulated Dried Kratom Leaf PowderView study →}, and to clinical case reports and poison-centre surveillance ^{27,28,29,38Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →Reference 29Dorey A et al. · 2026Case reportRhabdomyolysis, renal failure and chronic neurologic deficits after prolonged immobilization from use of a 7-hydroxymitragynine productView study →Reference 38Leonard JB et al. · 2026Kratom exposure cases reported to United States Poison Centers: 2016-July 2025View study →}.

Last checked: July 2026.

Isolate vs. Plant Studies

The split here is unusually clean and unusually consequential.

Essentially all pharmacology is isolate work. Receptor characterisation ^{3,4Reference 3Kruegel AC et al. · 2016Synthetic and Receptor Signaling Explorations of the Mitragyna Alkaloids: Mitragynine as an Atypical Molecular Framework for Opioid Receptor ModulatorsView study →Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →}, antinociception ^{2,6Reference 2Matsumoto K et al. · 2004AnimalAntinociceptive effect of 7-hydroxymitragynine in mice: Discovery of an orally active opioid analgesic from the Thai medicinal herb Mitragyna speciosaView study →Reference 6Berthold EC et al. · 2022AnimalThe Lack of Contribution of 7-Hydroxymitragynine to the Antinociceptive Effects of Mitragynine in Mice: A Pharmacokinetic and Pharmacodynamic StudyView study →}, respiratory depression ^{7,8Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →}, self-administration and discrimination ^{4,9Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →} were all done with purified 7-OH in rodents or cell systems. That is a methodological strength — the mechanism is defined at the molecular level rather than inferred from an extract — and it is also why the findings transfer straight to concentrated products, which are the isolate.

All human data are plant data. Every human exposure study measures 7-OH as an analyte in plasma after someone consumed leaf ^{11,12Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →Reference 12Huestis MA et al. · 2024Human Mitragynine and 7-Hydroxymitragynine Pharmacokinetics after Single and Multiple Daily Doses of Oral Encapsulated Dried Kratom Leaf PowderView study →}. No human has been given isolated 7-OH under controlled conditions. So the human evidence describes exposures where 7-OH is a minor, slowly generated metabolite at roughly a fifth to a third of mitragynine’s concentration ^{12Reference 12Huestis MA et al. · 2024Human Mitragynine and 7-Hydroxymitragynine Pharmacokinetics after Single and Multiple Daily Doses of Oral Encapsulated Dried Kratom Leaf PowderView study →} — the opposite of the exposure a 7-OH-enriched product produces.

The transferability caveat runs both ways. Whole-leaf safety data cannot be used to reassure about concentrated 7-OH, and isolate potency data should not be read back onto ordinary leaf kratom. Reviews of the field make this the central point ^{20Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →}, and product-analysis work confirms the two categories are chemically distinguishable in practice ^{23,24,32Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →Reference 24Sheehan D et al. · 2026Avoiding False Identification of 7-Hydroxymitragynine in Kratom Products Using a Multicriteria LC-MS ConfirmationView study →Reference 32Sharma A et al. · 2025Chemical Analysis and Alkaloid Intake for Kratom Products Available in the United StatesView study →}.

Its Role in the Plant

7-OH’s biosynthesis in M. speciosa is poorly characterised — appropriately for a compound present in trace amounts and detected inconsistently.

Structurally it is an oxidation product of mitragynine, and the plant data are consistent with an oxidative origin that is at least partly post-biosynthetic. Controlled post-harvest experiments varying withering time, drying temperature, cultivar and season found 7-OH averaging 0.02–0.04% of leaf alkaloid extract and detectable only in specific seasons, varying by cultivar — a genotype-by-environment signature rather than steady constitutive accumulation, in a study where mitragynine, speciogynine and paynantheine all responded predictably to withering and drying ^{15Reference 15Zhang M et al. · 2025Alkaloid biosynthesis in medicinal crop kratom (Mitragyna speciosa) varies with postharvest, genetic, and seasonal factorsView study →}. Within the plant it is tissue-restricted: quantified in leaves but not in shoots, where mitragynine is actually more concentrated ^{17Reference 17Krongrawa W et al. · 2026Effects of Botanical Variation, Plant Part, and Extraction Technique on Mitragynine and 7-Hydroxymitragynine in Kratom (Mitragyna speciosa) Extracts Quantified by a Validated HPLC-DAD MethodView study →}. Broader alkaloid surveys show total alkaloid production in kratom varies several-fold with season, geography, altitude and soil chemistry ^{18Reference 18Sengnon N et al. · 2023Seasonal and Geographic Variation in Alkaloid Content of Kratom (Mitragyna speciosa (Korth.) Havil.) from ThailandView study →}.

No ecological function has been demonstrated for 7-OH specifically. The reasonable reading is that kratom’s defensive chemistry is carried by the alkaloid fraction as a whole — dominated by mitragynine — and that 7-OH is a minor oxidative tail of that pathway rather than a target end-product.

Prevalence in Nature

7-OH is, as far as is documented, confined to Mitragyna speciosa and to organisms that metabolise mitragynine.

In leaf material it is a trace alkaloid: under 2% of the total alkaloid content, and often described simply as present in trace amounts ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Quantitatively it averages 0.02–0.04% of leaf alkaloid extract, with seasonal and cultivar gaps where it is not detected at all ^{15Reference 15Zhang M et al. · 2025Alkaloid biosynthesis in medicinal crop kratom (Mitragyna speciosa) varies with postharvest, genetic, and seasonal factorsView study →}. It occurs in the leaf specifically, not the shoots, and geographic origin shifts the balance — southern-Thai material ran relatively higher in 7-OH than northern in one comparison, while green-veined leaves carried more mitragynine than red-veined ^{17Reference 17Krongrawa W et al. · 2026Effects of Botanical Variation, Plant Part, and Extraction Technique on Mitragynine and 7-Hydroxymitragynine in Kratom (Mitragyna speciosa) Extracts Quantified by a Validated HPLC-DAD MethodView study →}. Its co-occurrence with mitragynine, paynantheine, speciogynine, corynantheidine, ajmalicine and the oxindoles mitraphylline and isomitraphylline is the standard leaf profile ^{16Reference 16León F et al. · 2009Phytochemical characterization of the leaves of Mitragyna speciosa grown in U.S.AView study →}.

Two non-botanical “sources” matter more in practice. The first is endogenous formation — 7-OH appears in the plasma of anyone who ingests mitragynine, at roughly 15–31% of the mitragynine concentration ^{11,12Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →Reference 12Huestis MA et al. · 2024Human Mitragynine and 7-Hydroxymitragynine Pharmacokinetics after Single and Multiple Daily Doses of Oral Encapsulated Dried Kratom Leaf PowderView study →}. The second is manufacture: over 98% of 7-OH in surveyed commercial “7-OH” products is of semi-synthetic origin, made from mitragynine rather than extracted from leaf, and identifiable as such from the over-oxidised byproducts that accompany it ^{23,30Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Analytical & Forensic Detection

7-OH is genuinely difficult to measure well, and several of the field’s headline claims rest on that difficulty.

Isobaric interference is the core problem. Kratom matrices contain many structurally related alkaloids and isomers that share 7-OH’s accurate mass. A 2026 UHPLC-HRMS study of authentic leaf and 38 commercial products found multiple overlapping chromatographic peaks at m/z 415.2227, and demonstrated that relying on accurate mass alone — or on the commonly monitored m/z 415 → 190 transition — can generate false-positive 7-OH identifications in botanical matrices. Reliable confirmation needs chromatographic resolution plus orthogonal MS/MS criteria ^{24Reference 24Sheehan D et al. · 2026Avoiding False Identification of 7-Hydroxymitragynine in Kratom Products Using a Multicriteria LC-MS ConfirmationView study →}. Any claim that leaf material “contains” 7-OH should be read against that standard.

Stability shapes what a lab can find. In refrigerated biological matrix, mitragynine is stable for about 30 days but 7-OH only about 7, with concentrations dropping over 50% by 60 days; methanolic preparations held at −20 °C are stable for months ^{25Reference 25Osawa KA · 2025Postmortem distribution of mitragynine and 7-hydroxymitragynine in 51 casesView study →}. Delayed casework will under-report 7-OH.

Postmortem casework. A study of 51 postmortem cases found a heart-to-femoral blood ratio of 1.37 for mitragynine and 1.08 for 7-OH, suggesting some postmortem redistribution for mitragynine but little for the metabolite, and reported large mitragynine : 7-OH ratios of about 30.9 in femoral blood and 32.4 in heart blood, against 14.8 in vitreous humour and 16.9 in urine ^{25Reference 25Osawa KA · 2025Postmortem distribution of mitragynine and 7-hydroxymitragynine in 51 casesView study →}. Those ratios are the natural fingerprint of leaf exposure — a much lower ratio points elsewhere, and forensic toxicologists have begun flagging 7-OH-dominant cases as a distinct pattern ^{26Reference 26Papsun DM et al. · 2026Papsun DM, Schroeder W, Brower J, Krotulski A, Ellefsen K (2026). 7-Hydroxymitragynine: Not Your Garden Variety Kratom. American Journal of Forensic Medicine and Pathology. https://pubmed.ncbi.nlm.nih.gov/42135874/View study →}.

The surveillance blind spot. Because forensic laboratories have historically targeted mitragynine as kratom’s marker and 7-OH has not been federally controlled in the US, minor-alkaloid analysis was often not performed at all — which regulators acknowledge means law-enforcement encounter data understate 7-OH’s prevalence ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Distinguishing ingestion of concentrated 7-OH from ordinary kratom use is complicated further by the fact that 7-OH is a normal metabolite of mitragynine in anyone who took the leaf ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Discovery & Synthesis

7-OH was isolated from the plant, and the date matters to the “metabolite or constituent” argument. Ponglux, Takayama and colleagues reported it in Planta Medica in December 1994 as a new indole alkaloid from Mitragyna speciosa in Thailand, naming it 7α-hydroxy-7H-mitragynine ^{1Reference 1Ponglux D et al. · 1994A New Indole Alkaloid, 7 alpha-Hydroxy-7H-mitragynine, from Mitragyna speciosa in ThailandView study →}. It sat as a phytochemical curiosity for a decade.

Its pharmacological debut came in 2004, when Matsumoto and colleagues at Chiba University characterised it as an opioid agonist with higher µ affinity than κ or δ, potent antinociception in mice exceeding morphine’s, and — the finding that drove a generation of medicinal chemistry — retained potency by the oral route, where morphine was only weakly active. Their paper is titled, plainly, the discovery of an orally active opioid analgesic from a Thai medicinal herb ^{2Reference 2Matsumoto K et al. · 2004AnimalAntinociceptive effect of 7-hydroxymitragynine in mice: Discovery of an orally active opioid analgesic from the Thai medicinal herb Mitragyna speciosaView study →}. In 2019 its status changed again when it was shown to be an active CYP3A metabolite of mitragynine with brain concentrations plausibly sufficient to carry mitragynine’s analgesia ^{5Reference 5Kruegel AC et al. · 2019Kruegel AC, Uprety R, Grinnell SG, et al. (2019). 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science. https://pubmed.ncbi.nlm.nih.gov/31263758/View study →}, and in 2024 that conversion was confirmed in humans ^{11Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}.

Manufacture today is semi-synthetic, from mitragynine. Regulators note that 7-OH can be produced from mitragynine by a short chemical oxidation, and that synthetic and naturally occurring 7-OH are chemically identical, with identical receptor pharmacology regardless of origin ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Chemical analysis of the consumer market confirms the practical consequence: over 98% of 7-OH-labelled products bear the signature of semi-synthetic manufacture, not extraction ^{23Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}. Extraction from leaf is not a viable commercial route — the leaf simply does not contain enough. No preparation, oxidation, enrichment or synthesis details are given here.

Patents: not yet researched.

Legal Status

Status as reported here was verified on 29 July 2026 against the primary regulatory record; this area is moving quickly and should be re-checked before being relied on.

United States — federal (as of 29 July 2026): not yet scheduled, but a temporary Schedule I order is imminent for concentrated 7-OH. The sequence, per the Drug Enforcement Administration’s own notice of intent ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}:

• 28 July 2025 — HHS transmitted to DEA a scientific and medical evaluation recommending control of 7-hydroxymitragynine above a specified threshold in Schedule I.
• 24 February 2026 — the DEA Administrator notified the Assistant Secretary for Health of the intent to schedule temporarily; on 6 March 2026 HHS replied that there were no INDs or NDAs for the substance and that it had no objection.
• 1 July 2026 — DEA announced the start of temporary scheduling; the notice of intent (Docket No. DEA-1570) was published in the Federal Register on 6 July 2026.
• The notice provides the statutory 30-day notice: the temporary scheduling order may be published on or after 5 August 2026 and takes effect on publication, running two years with a possible one-year extension.

As of 29 July 2026 the order had not yet issued — 7-OH was still federally uncontrolled, and the notice of intent is a notice, not a final order ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

The threshold is the whole point of the design. The proposed control does not cover kratom leaf generally. It reaches ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}:

• (A) botanical M. speciosa material containing more than 0.050% 7-OH on a dry-weight basis; and
• (B) any alternative article — synthetic, or leaf-derived material further processed into extracts, concentrates, edibles or pressed pills, including material chemically or thermally transformed — containing 7-OH above 0.050% w/w, w/v or v/v, or more than 1.00 mg per article.

Ordinary leaf, which runs far below that threshold, is left outside. A companion notice covers three related substances outright, without a threshold: mitragynine pseudoindoxyl, MGM-15 (dihydro-7-hydroxymitragynine) and MGM-16 (9-fluoro-dihydro-7-hydroxymitragynine) ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

United States — FDA. Between June and July 2025 FDA issued seven warning letters to firms marketing 7-OH products, stating that 7-OH is not an FDA-approved drug, that no food-additive regulation permits it in food, and that it is a “new dietary ingredient” with no evidence of marketing as a dietary ingredient before 15 October 1994 — several letters also deeming such supplements adulterated, and one flagging gummies whose packaging could appeal to children ^{30,31Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →Reference 31U.S et al. · 2025FDA Issues Warning Letters to Firms Marketing Products Containing 7-HydroxymitragynineView study →}.

United States — states. State law already varies widely and, per the federal notice, is not preempted by the coming federal order ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. As catalogued in that notice: nine states (Alabama, Arkansas, Florida, Indiana, Kentucky, Louisiana, Ohio, Vermont, Wisconsin) prohibit 7-OH consumption; Arizona, Colorado, South Carolina and Texas cap 7-OH as a percentage of total alkaloid content; 19 states have enacted a Kratom Consumer Protection Act imposing manufacturing, labelling and age requirements; and Illinois, New Hampshire, North Carolina and Tennessee have local bans. Mississippi’s limit is among the strictest at 1% of total alkaloid content or 0.5 mg per container.

Elsewhere. Kratom itself — and with it 7-OH — is controlled, restricted or banned in a range of countries, while Thailand decriminalised kratom in 2021; the international picture is inconsistent and is the subject of an active regulatory-science literature rather than a settled position ^{20,39Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 39Henningfield JE et al. · 2024Kratom safety and toxicology in the public health context: research needs to better inform regulationView study →}. Anyone relying on the status in a specific jurisdiction should check that jurisdiction’s current law directly.

Toxicity & Safety

7-OH carries a poisonous flag. It is a potent µ-opioid agonist with documented respiratory depression, dependence, and fatal and non-fatal overdose cases, sold in unregulated products of unverified content, with no approved medical use and no established safe intake ^{20,23,30Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Respiratory Depression & Overdose

The dominant acute danger, and a conventional opioid one. In rats, 7-OH depressed minute volume with 4.5-fold morphine’s potency, fully reversed by naloxone ^{8Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →}; in mice its respiratory depression was dose-dependent with no ceiling, unlike mitragynine’s ^{7Reference 7Hill R et al. · 2022The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynineView study →}. A 2026 clinical case describes cardiopulmonary arrest after reported 7-OH use, reversed with naloxone ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Risk rises sharply with co-ingestion of other CNS depressants — opioids, benzodiazepines, alcohol — which is the common pattern in fatal casework ^{30,38Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →Reference 38Leonard JB et al. · 2026Kratom exposure cases reported to United States Poison Centers: 2016-July 2025View study →}.

Dependence, Withdrawal & Addiction

7-OH is reinforcing in the classical opioid sense: self-administered by rats, fully substituting for morphine, and increasing subsequent morphine intake after exposure ^{4,9Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →}. In humans, published cases describe escalating use, dependence and withdrawal severe enough to require inpatient medically managed detoxification, with buprenorphine used for stabilisation ^{27,28Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →}. Regulatory adverse-event surveillance found drug dependence and withdrawal syndrome the most frequently reported events ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Users commonly report short duration of effect and frequent redosing, a pattern that accelerates dependence ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Product Risk: Unknown Content, Unknown Purity

An unusually large share of the risk is not pharmacological but manufacturing. Labelled and measured 7-OH content diverge substantially, labelled doses in surveyed products span 0.001–33.6 mg per serving (with the regulatory survey reporting 1–700 mg), and over-oxidised byproducts from the manufacturing route are detectable in commercial material ^{23Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}. Some products additionally contain mitragynine pseudoindoxyl, another potent µ agonist, without saying so ^{22,30Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. 7-OH also degrades to 3-dehydromitragynine under simulated gastric conditions ^{23Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}. Confectionery-style formats — gummies, colourful packaging — raise a specific paediatric exposure concern ^{20,30Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Other Reported Harms

Poison-centre and clinical reports describe nausea and vomiting, agitation, confusion, loss of consciousness, seizure, sweating, tachycardia, hypertension and difficulty breathing in 7-OH exposures ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. Published cases include rhabdomyolysis with renal failure and lasting neurological deficits after prolonged immobilisation on a 7-OH product ^{29Reference 29Dorey A et al. · 2026Case reportRhabdomyolysis, renal failure and chronic neurologic deficits after prolonged immobilization from use of a 7-hydroxymitragynine productView study →} and, at the extreme end, severe psychiatric decompensation ^{20Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →}. US poison-centre kratom exposures have risen year on year through 2025 ^{38Reference 38Leonard JB et al. · 2026Kratom exposure cases reported to United States Poison Centers: 2016-July 2025View study →}.

Drug Interactions

Two mechanisms matter. First, CYP3A4 governs 7-OH formation from mitragynine — a CYP3A4 inhibitor such as itraconazole cuts 7-OH exposure by roughly half after kratom ingestion ^{11Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →}, so inhibitors and inducers of CYP3A4 will shift the metabolite exposure of anyone using leaf kratom. Second, kratom inhibits CYP3A/CYP2C19 and related isoforms, creating interaction potential with a broad range of prescription medicines ^{33Reference 33Tanna RS et al. · 2023Clinical Assessment of the Drug Interaction Potential of the Psychotropic Natural Product KratomView study →}. Both alkaloids are also P-glycoprotein substrates and inhibitors, adding a transporter-level interaction layer ^{14Reference 14Yusof SR et al. · 2019Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studiesView study →}. Additive risk with opioids, benzodiazepines, alcohol and other CNS depressants is the clinically dominant combination hazard ^{30,38Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →Reference 38Leonard JB et al. · 2026Kratom exposure cases reported to United States Poison Centers: 2016-July 2025View study →}.

Reproductive & Developmental Findings

There is no reproductive toxicity study of isolated 7-OH. What exists is clinical: neonatal abstinence syndrome has been reported in infants born to mothers who used kratom during pregnancy, presenting like opioid withdrawal and requiring treatment ^{36,37Reference 36Eldridge WB et al. · 2018Neonatal Abstinence Syndrome Due to Maternal Kratom UseView study →Reference 37Davidson L et al. · 2019Natural drugs, not so natural effects: Neonatal abstinence syndrome secondary to ‘kratom’View study →}. Since 7-OH is the opioid-active alkaloid — and a concentrated product delivers far more of it than leaf — the neonatal-withdrawal risk should be read as at least as applicable to 7-OH as to kratom, and no safe level of exposure is established. The intake decision for pregnancy and lactation belongs to the kratom monograph, not to this molecule page.

Safety at a Glance

☠️ PoisonousControlled substanceSedative interactionsDrug interactions

• A conventional opioid, not a gentle botanical. 7-OH is a high-efficacy µ-opioid agonist that is self-administered by rats, fully substitutes for morphine, and depresses respiration more potently than morphine — reversible with naloxone ^{4,8,9Reference 4Obeng S et al. · 2021In vitroPharmacological Comparison of Mitragynine and 7-Hydroxymitragynine: In Vitro Affinity and Efficacy for μ-Opioid Receptor and Opioid-Like Behavioral Effects in RatsView study →Reference 8Zuarth Gonzalez JD et al. · 2025AnimalMitragynine and 7-hydroxymitragynine: Bidirectional effects on breathing in ratsView study →Reference 9Hemby SE et al. · 2019Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynineView study →}.
• Real dependence and withdrawal. Human cases document escalating use, physical dependence and withdrawal requiring inpatient buprenorphine-managed detoxification ^{27,28Reference 27Wightman RS · 2025Case reportA Case of 7-OH Mitragynine Use Requiring Inpatient Medically Managed WithdrawalView study →Reference 28Fenske E et al. · 2026Case reportBuprenorphine for the Management of 7-Hydroxymitragynine (7-OH) Use: A Retrospective Case SeriesView study →}.
• No approved medical use, no safe intake established. No IND or NDA exists, no controlled human trial has defined a safe dose, and fatal and non-fatal overdoses are documented ^{20,30Reference 20Alsbrook S et al. · 2025From kratom to 7-hydroxymitragynine: evolution of a natural remedy into a public-health threatView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.
• Concentrated products are not kratom leaf. Over 98% of surveyed “7-OH” products are semi-synthetic, labelled content is frequently wrong, and some also contain mitragynine pseudoindoxyl undeclared ^{22,23Reference 22Hill K et al. · 2025De facto opioids: Characterization of novel 7-hydroxymitragynine and mitragynine pseudoindoxyl product marketingView study →Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →}.
• CNS-depressant combinations are the main killer. Fatal casework overwhelmingly involves co-ingested opioids, benzodiazepines or other depressants ^{30,38Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →Reference 38Leonard JB et al. · 2026Kratom exposure cases reported to United States Poison Centers: 2016-July 2025View study →}.
• CYP3A4 and P-gp interactions. CYP3A4 inhibitors and inducers change 7-OH exposure from kratom; kratom itself inhibits CYP3A/2C19 and both alkaloids interact with P-glycoprotein ^{11,14,33Reference 11Mongar P et al. · 2024Effects of Itraconazole on Pharmacokinetics of Mitragynine and 7-Hydroxymitragynine in Healthy VolunteersView study →Reference 14Yusof SR et al. · 2019Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studiesView study →Reference 33Tanna RS et al. · 2023Clinical Assessment of the Drug Interaction Potential of the Psychotropic Natural Product KratomView study →}.
• Legal status is in flux. A US temporary Schedule I order for 7-OH above a 0.050% / 1 mg threshold may take effect from 5 August 2026; several states already prohibit or cap it. Check current law directly ^{30Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}.

Dosage

No dose for effect is given here, and none should be inferred. 7-OH has no approved medical use, no controlled human trial has established a safe or effective intake, and product labels are demonstrably unreliable ^{23,30Reference 23Avula B et al. · 2026Quantitative analysis of 7-hydroxymitragynine in commercial kratom products and its stability under chemical and physiological conditionsView study →Reference 30Drug Enforcement Administration · 2026Schedules of Controlled Substance: Temporary Placement of 7-Hydroxymitragynine Above a Specified Threshold in Schedule IView study →}. The figures below describe reported exposure, for interpreting the literature and clinical casework.

The gap between the third and fourth rows is the entire public-health story of this molecule: leaf exposure generates a small, slow, rate-limited amount of 7-OH, while a concentrated product can deliver orders of magnitude more, immediately. These are research and forensic reference figures, not a personal recommendation.

References

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