MGM-16

MGM-16 is a fluorinated semi-synthetic derivative of mitragynine, first reported by the Takayama / Matsumoto research group in J Pharmacol Exp Ther 2014 (PMID 24345467). It’s structurally adjacent to MGM-15, the same saturated 7-hydroxymitragynine scaffold with a single fluorine added to the indole ring. The change is small chemically; the reported potency difference is large.

This page exists because the compound is starting to come up in recovery-community conversations and in state-level scheduling discussions. Most of what circulates is community awareness rather than verified information. This page tries to bridge that gap: it stays inside what one peer-reviewed paper and a few government documents establish, and it labels the (many) gaps as gaps.

Structure and chemistry

Structure. MGM-16 is the fluorine-substituted analog of MGM-15 (which is itself dihydro-7-hydroxymitragynine, the saturated indoline reduction product of 7-OH). MGM-16 adds a single fluorine atom on the indole ring of MGM-15.

A quick note on the numbering. The community label is “9-fluoro MGM-15.” That’s correct in the IUPAC systematic numbering used in the published paper’s full chemical name. The same atom is also referred to as the 10-position in the natural-product numbering that’s standard for mitragynine itself, the published paper calls the chemical precursor “10-fluoro-7-hydroxymitragynine” before it’s reduced to MGM-16. They are the same atom; the two numbers reflect two different ring-numbering conventions in the chemistry literature. Don’t be thrown by seeing both numbers in different papers.

Synthesis. Per the Matsumoto 2014 paper, MGM-16 is prepared by sodium borohydride (NaBH₄) reduction of 10-fluoro-7-hydroxymitragynine. Mechanically the same reduction step that produces MGM-15 from 7-OH, with a fluorine already on the precursor.

IUPAC name (from the published paper): (E)-methyl 2-((2S,3S,7aS,12aR,12bS)-3-ethyl-9-fluoro-7a-hydroxy-8-methoxy-1,2,3,4,6,7,7a,12,12a,12b-decahydroindolo[2,3-a]quinolizin-2-yl)-3-methoxyacrylate.

As of this writing, no PubChem CID or CAS registry number could be located.

Measured data, and the one paper it traces to

Every quantitative pharmacology claim about MGM-16 traces back to a single 2014 paper. No independent replication has been published. That’s where the evidence centers.

From Matsumoto et al., J Pharmacol Exp Ther 2014:

The ”≈ 240× the potency of morphine” claim that circulates in community discussions comes from the ED₅₀ ratio above, mouse tail-flick antinociception, oral administration. It’s a real number from a real paper. It’s also a single in-vivo measurement in one species, one assay, one route, one comparator. Use it as that, not as a free-standing potency statement.

Gaps in the evidence

These absences are part of the evidence picture. None of the following has been published for MGM-16 specifically:

• No human data of any kind. No clinical trials, no case reports, no poison-center entries, no human toxicology series.
• No pharmacokinetic data. No published half-life, plasma concentration data, metabolism profile (CYP characterization), bioavailability number, clearance, or protein-binding data.
• No abuse-liability or dependence studies on MGM-16 specifically. (An earlier paper from the same group studied a structurally related compound called MGM-9 and reported “weak rewarding effects”, that finding is for MGM-9, not MGM-16, and shouldn’t be transferred across.)
• No withdrawal-syndrome data on MGM-16 specifically.
• No replication by an independent lab. The 2014 paper is the sole primary report; subsequent literature that mentions MGM-16 cites the 2014 paper rather than re-measuring.

Presence in the regulatory and forensic record

The headline finding from the regulatory record is that MGM-16 does not show up.

A California State Senate Committee on Health 2026 background paper on kratom and 7-OH contains a single, unsourced reference to MGM-16, calling it “the most potent” of the mitragynine-related opioids in the published literature and noting that it is “currently prohibitively expensive to synthesize.” The paper provides no detection data, forensic citations, or independent sourcing behind those characterizations. The community framing that MGM-16 is “the next 7-OH” or that it’s already in products is not, as of this writing, supported by any documented forensic detection.

Specifically:

• The Ohio Board of Pharmacy’s 2025 mitragynine-related-compounds scheduling document confirms MGM-15 detection in commercially-available tablets in September 2025. The same document does not mention MGM-16.
• FDA warning letters and import alerts for the 7-OH wave of July 2025 named 7-OH and its vendors. MGM-16 is not in those documents.
• DEA microgram bulletins have no entry for MGM-16 as of this writing.
• No forensic-chemistry or analytical-chemistry publication documents MGM-16 in a US-seized consumer product.

If MGM-16 starts appearing in products, that record will change, and this page should be updated when it does. The right framing today is “present in the published research literature, named in scheduling-policy discussion, not yet documented in commercial products” rather than the “emerging street drug” framing the community sometimes uses.

Regulatory status

• Federal (US): on July 1, 2026, DEA filed a notice of intent to temporarily place MGM-16 in Schedule I by name, alongside MGM-15 and mitragynine pseudoindoxyl (Docket DEA-1644). The earliest the order can take effect is August 5, 2026. See The Federal 7-OH Ban for dates and process.
• Ohio: covered generically under the Ohio Admin Code 4729:9-1-01.1 “mitragynine-related compounds” Schedule I rule (effective December 12, 2025). The rule’s class-level language presumably reaches MGM-16, though the document itself does not name MGM-16 individually.
• Other states: as of this writing, no state scheduling document has been located that names MGM-16 individually.
• International: as of this writing, no specific scheduling has been located.

Sources

• Matsumoto K, Takayama H et al., J Pharmacol Exp Ther 2014;348(3):383-392 (PMID 24345467, PMC6067406) , the foundational and only primary pharmacology paper on MGM-16
• Matsumoto K et al., Neuropharmacology 2008;55(2):154-65 (PMID 18550129) , earlier paper from the same research program (MGM-9), establishes the multi-paper program of fluorinated mitragynine derivatives
• Bhowmik S, Galeta J et al., Nat Commun 2021;12:3858 , medicinal-chemistry context for halogen substitution on the indole ring of mitragynine analogs (does not study MGM-16 directly)
• California State Senate Committee on Health, Kratom and 7-Hydroxymitragynine background paper, Feb 2026 , state-government characterization including the “prohibitively expensive to synthesize” framing
• Ohio Board of Pharmacy, mitragynine-related compounds Schedule I classification , does not name MGM-16 individually; covers the class

Reference, not advice. Everything on this page is sourced from published literature and government documents. None of it tells you what to take, how to taper, or how to evaluate a specific product you’re using, those decisions belong with a clinician familiar with your situation.

Where to read next

• MGM-15: the non-fluorinated parent compound; the one with current consumer-product detection
• 7-OH: the upstream compound from which both MGM-15 and MGM-16 are derived
• Morphine vs. Mitragyna Alkaloids , structural-pharmacology comparison of the mitragynine derivative family
• Chemical Structures (Appendix) , 2D skeletal-formula diagrams for the related compounds (MGM-16 is not yet in the appendix)
• Telehealth Providers: for finding a prescriber experienced with kratom and 7-OH dependence