mitragynine
noun
mi·trag·y·nine
mi-ˈtra-jə-ˌnēn 
: the principal psychoactive indole alkaloid C23H30N2O4 that is found in kratom and that binds as an agonist to certain opioid receptors to produce effects (such as analgesia) similar to that of opioids
Kratom contains more than 40 phytochemicals in the class of indole alkaloids, the primary one being mitragynine …—
David Kiefer
David KieferBags of powder line the shelves at Laughing Lion, each with a varying level of mitragynine, the compound that interacts with opioid receptors in the brain, and is said to produce those good feelings, alertness, decreased pain or relaxation, depending on the amount.—Jennifer Mulson
compare 7-hydroxymitragynine
Jennifer MulsonExamples of mitragynine in a Sentence
Recent Examples on the Web
This matters because mitragynine is a weak opioid, while 7OH is a much stronger opioid, which can increase the intensity of the opioid effects and lead to overdose.
—Andrew Kolodny, The Conversation, 2 Apr. 2026
The Tarrant County medical examiner said Hamilton’s accidental death was due to mitragynine toxicity, one of the active ingredients of kratom.
—Paul Flahive, Austin American Statesman, 1 Apr. 2026
Smith, the leading kratom researcher, has said the emphasis on semisynthetic 7-OH is odd because there is no evidence justifying it, and because the natural kratom alkaloid mitragynine still converts to 7-OH during manufacturing and in the body.
—Kristen Rogers, CNN Money, 27 Mar. 2026
This is because the two major ingredients, mitragynine and 7-hydroxymitragynine, have major psychoactive effects.
—Josh Kelly, Oklahoman, 26 Mar. 2026
The Medical Examiner deemed her death a suicide from the effects of mitragynine, 7-hydroxymitragynine, quetiapine, and mirtazapine.
—Matthew Rodriguez, CBS News, 21 Mar. 2026
The medical examiner determined her death was due to the effects of mitragynine, 7-hydroxymitragynine, quetiapine and mirtazapine.
—Clara Harter, Los Angeles Times, 21 Mar. 2026
Naroditsky’s concentrations of methamphetamine and mitragynine, the primary active chemical in kratom, were not by themselves fatal, according to the report.
—Joe Marusak, Charlotte Observer, 21 Jan. 2026
Naroditsky had methamphetamine, amphetamine, 7-hydroxymitragynine and mitragynine in his system at the time of death, according to a toxicology report provided to NBC News by the North Carolina Office of the Chief Medical Examiner.
—Mirna Alsharif, NBC news, 20 Jan. 2026
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Andrew Kolodny, The Conversation, 2 Apr. 2026
The Tarrant County medical examiner said Hamilton’s accidental death was due to mitragynine toxicity, one of the active ingredients of kratom.
—Paul Flahive, Austin American Statesman, 1 Apr. 2026
Smith, the leading kratom researcher, has said the emphasis on semisynthetic 7-OH is odd because there is no evidence justifying it, and because the natural kratom alkaloid mitragynine still converts to 7-OH during manufacturing and in the body.
—Kristen Rogers, CNN Money, 27 Mar. 2026
This is because the two major ingredients, mitragynine and 7-hydroxymitragynine, have major psychoactive effects.
—Josh Kelly, Oklahoman, 26 Mar. 2026
The Medical Examiner deemed her death a suicide from the effects of mitragynine, 7-hydroxymitragynine, quetiapine, and mirtazapine.
—Matthew Rodriguez, CBS News, 21 Mar. 2026
The medical examiner determined her death was due to the effects of mitragynine, 7-hydroxymitragynine, quetiapine and mirtazapine.
—Clara Harter, Los Angeles Times, 21 Mar. 2026
Naroditsky’s concentrations of methamphetamine and mitragynine, the primary active chemical in kratom, were not by themselves fatal, according to the report.
—Joe Marusak, Charlotte Observer, 21 Jan. 2026
Naroditsky had methamphetamine, amphetamine, 7-hydroxymitragynine and mitragynine in his system at the time of death, according to a toxicology report provided to NBC News by the North Carolina Office of the Chief Medical Examiner.
—Mirna Alsharif, NBC news, 20 Jan. 2026
Cite this Entry
“Mitragynine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mitragynine. Accessed 5 Apr. 2026.
Copy CitationMedical Definition
mitragynine
noun
mi·trag·y·nine
mi-ˈtraj-ə-ˌnēn
: the principal psychoactive indole alkaloid C23H30N2O4 that is found in kratom and that binds as an agonist to certain opioid receptors to produce effects (such as analgesia) similar to that of opioids
Withdrawal from chronic mitragynine induces opioid-like somatic withdrawal, locomotor hypersensitivity for further pharmacological stimulation and enhances anxiety levels for up to 48 hours.—Nurul H. M. Yusoff et al., Addiction Biology
compare 7-hydroxymitragynine
Nurul H. M. Yusoff et al., Addiction BiologyLove words? Need even more definitions?
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