Mitragynine (Kratom Indole Alkaloid · Mu-Opioid Partial Agonist · Informational)
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | Mitragynine |
| Chemical class | Alkaloid — Indole (corynanthe-type monoterpenoid indole alkaloid) |
| CAS | 4098-40-2 |
| Primary source | Mitragyna speciosa (kratom), leaves |
| Key applications | Mu-opioid partial agonist; researched for pain and opioid withdrawal; controlled/variable status; informational-only |
| Claim strength | Emerging (clinical); controlled/variable status |
| Typical form | Research reference; not offered as a supplement ingredient |
| Buy from Herbuno | Informational reference — see HerbIQ Compound Index → |
Name origin: Mitragynine is named for Mitragyna speciosa, the kratom tree, and is a corynanthe-type monoterpenoid indole alkaloid — the plant’s most abundant psychoactive constituent, typically the dominant alkaloid in dried leaf. Traditional use: In Thailand, Malaysia, and neighbouring regions, kratom leaves have long been chewed fresh or brewed as a tea by manual labourers to relieve fatigue and pain and, in folk practice, to ease opioid withdrawal. This traditional use of the whole leaf, in which mitragynine is delivered at modest concentrations alongside dozens of minor alkaloids, is quite different from the concentrated and semi-synthetic products that have appeared in Western markets. Research trajectory: Mitragynine is a partial agonist at the mu-opioid receptor and a competitive antagonist at the kappa and delta receptors; in mice it is converted to the far more potent metabolite 7-hydroxymitragynine, which mediates much of its analgesic effect, so that route of administration and metabolism strongly shape its activity Kruegel 2019. Its clinical pharmacology — atypical opioid signalling, additional effects on adrenergic, serotonergic, and dopaminergic pathways, and its real-world use as a self-managed alternative to opioids — has been reviewed in the context of its being an increasingly used but incompletely characterised substance Prozialeck 2021. Safety and legal context: Kratom and mitragynine are controlled or restricted in many jurisdictions and carry genuine dependence and safety concerns; this page is a factual research reference and explicitly not a sourcing offer.
Evidence for Mitragynine Applications
Opioid-receptor pharmacology: Mitragynine is a partial mu-opioid receptor agonist with lower potency than morphine, and unlike full agonists it does not strongly activate the beta-arrestin-2 pathway that is linked to respiratory depression, which is the basis for its description as an atypical opioid Prozialeck 2021. This signalling profile is central to both the scientific interest in the compound and the caution around it. Claim strength: Emerging.
Metabolite-dependent analgesia: In animal studies mitragynine is converted to 7-hydroxymitragynine, a much more potent mu-opioid agonist that mediates a large part of the analgesic effect; mitragynine itself reaches high brain concentrations relative to its modest receptor affinity, suggesting its activity depends heavily on this metabolic conversion and on the route of administration Kruegel 2019. Claim strength: Emerging.
Opioid-withdrawal context: Kratom has traditionally, and increasingly in Western settings, been used for the self-management of pain and opioid withdrawal, and reviews document this use pattern while emphasising that controlled clinical evidence remains limited and that neither kratom nor its constituents are approved as safe and effective for any condition Prozialeck 2021. Claim strength: Emerging.
Multi-target activity: Beyond opioid receptors, mitragynine affects adrenergic, serotonergic, and dopaminergic pathways, which contributes to its complex profile combining stimulant-like effects at lower exposure with sedative, opioid-like effects at higher exposure Prozialeck 2021. Claim strength: Emerging.
Product-form variability: Kratom leaf alkaloid content varies widely with source, cultivar, and preparation, and concentrated or enriched products differ chemically from traditional leaf, so the pharmacology and risk of a given kratom product cannot be assumed from the mitragynine content of leaf alone Prozialeck 2021. Claim strength: Emerging.
This compound is documented for research and formulator education purposes. For commercially available botanical ingredients, explore the HerbIQ Compound Index →
Dosage & Formulator Specification
Mitragynine is documented here for research and formulator education only; Herbuno does not offer it as a botanical ingredient. It has opioid-receptor activity, recognised dependence potential, and controlled or restricted legal status in many jurisdictions, so it is not appropriate for supplement formulation, and no consumer dosing is provided.
Kratom leaf alkaloid content varies widely with source and preparation, and concentrated or semi-synthetic products raise additional safety and regulatory concerns distinct from those of traditional leaf. Any formulator encountering kratom material must treat mitragynine as a regulated substance whose legal status has to be verified in every target market before any handling is contemplated.
From an analytical standpoint, kratom material is characterised by HPLC or LC-MS quantification of mitragynine and 7-hydroxymitragynine, since the ratio of these two alkaloids — and particularly any enrichment of the more potent 7-hydroxymitragynine — materially changes the safety profile. This analytical distinction between traditional leaf and enriched product is central to any responsible discussion of the material, even though it does not create a supplement pathway.
This monograph provides factual pharmacological and legal context within the HerbIQ index, connecting mitragynine to its metabolite 7-hydroxymitragynine and its diastereomer speciociliatine covered elsewhere, and does not constitute sourcing guidance or a recommendation for use.
Frequently Asked Questions — Mitragynine
What is mitragynine?
Mitragynine is the principal indole alkaloid of Mitragyna speciosa (kratom), a tree native to Southeast Asia. It is a corynanthe-type monoterpenoid indole alkaloid and a partial agonist at the mu-opioid receptor, and it is the main compound behind kratom’s opioid-like effects.
What is the legal status of mitragynine and kratom?
Kratom and its alkaloids are controlled or restricted in many countries and in some sub-national jurisdictions, and unregulated in others, so legal status varies widely and changes over time. This page is informational only and is not a sourcing offer; anyone considering the compound must verify its status in the relevant territory.
Why is mitragynine informational-only in HerbIQ?
Because of its opioid-receptor activity, recognised dependence potential, and variable controlled status, mitragynine is documented for research and formulator education only and is not offered as a botanical ingredient by Herbuno.
How does mitragynine differ from classical opioids?
Mitragynine is a partial mu-opioid agonist with lower potency than morphine and, unlike full agonists, does not strongly recruit the beta-arrestin-2 signalling pathway associated with respiratory depression. It is often described as an atypical opioid, and much of its analgesic effect in animals is actually mediated by its more potent metabolite, 7-hydroxymitragynine; safety concerns nonetheless remain.
Related compounds: 7-Hydroxymitragynine, Speciociliatine, Ibogaine, Yohimbine
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
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