Kratom

# Research Output: Kratom (*Mitragyna speciosa*)

**PSX ID:** PSX-0222 | **Slug:** kratom | **Provenance ID:** 9c29a38e-cea2-4dc4-ad76-e28f2ae8e9fc
**Research date:** 2026-05-13

---

## Botanical Identity

### Accepted Taxonomy
*Mitragyna speciosa* Korth. (Royal Botanic Gardens Kew / POWO [Ref 57]). Family **Rubiaceae** (order Gentianales — the coffee family). First published in 1841 by Pieter Willem Korthals, the Dutch botanist who described the genus *Mitragyna*. The species epithet *speciosa* means "showy" or "beautiful" in Latin, referring to the large flower heads.

**Accepted binomial:** *Mitragyna speciosa* (Korthals) Havil. — full citation often given as *Mitragyna speciosa* Korth.

**Synonyms (4 confirmed by POWO [Ref 57]):**
- *Nauclea speciosa* (Korth.) Miq. [homotypic]
- *Stephegyne speciosa* (Korth.) Korth. [homotypic]
- *Nauclea korthalsii* Steud. [heterotypic]
- *Nauclea luzoniensis* Blanco [heterotypic]

### Native Range & Distribution
Native range: **Southern Indo-China to New Guinea** [Ref 57]. Specifically documented in: Borneo, Cambodia, Malaya (peninsular Malaysia), Myanmar, New Guinea, Philippines, Sumatra, Thailand, and Vietnam. Grows primarily in the **wet tropical biome** — found in tropical and subtropical forests, often in swampy or lowland riverine areas [Ref 57]. Major commercial production is in Indonesia (particularly Borneo/Kalimantan), where the plant is both wild-harvested and cultivated.

### Morphological Description
A medium to large **tropical deciduous and evergreen tree** reaching up to 25 m in height, with a trunk diameter of 0.9 m [Ref 2]. Leaves are dark green, glossy, ovate-elliptical, 15–45 cm long. Flowers are yellow, globular, borne in terminal panicles. The fruit is a capsule containing small, winged seeds. The plant is in the same family as coffee (*Coffea spp.*) and quinine (*Cinchona spp.*) [Ref 20].

### Cultivation Status
Both **wild-harvested and cultivated**. Wild populations exist throughout native range. Commercial cultivation concentrated in Indonesia (Borneo), where leaf harvests are exported globally. The plant grows vigorously in tropical climates with high humidity and well-drained to seasonally waterlogged soils. No formal CITES listing.

### Misidentification Risk
No published reports of toxic look-alike misidentification found in the reviewed literature. *Mitragyna* genus (8 species) are morphologically distinct trees in their native range; confusion risk is low in Southeast Asian traditional contexts. For dried powder preparations sold in Western markets, adulterant contamination and mislabeling are the primary identification risks — not botanical misidentification.

### Discrepancy with Seed Data
**⚠️ FLAG:** The brief lists substance Type as "preparation." Botanically, kratom is a plant (*Mitragyna speciosa*); kratom powder, tea, and extracts are *preparations* made from its leaves. The Type should be corrected to "plant" with a note that commercially available forms are preparations. Genus/species, family, and native range were absent from seed data — all confirmed and provided here.

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## Alkaloid / Cannabinoid Profile

### Quantified Major Alkaloids
The alkaloid profile of kratom has been systematically characterized by UPLC-MS/MS across leaf extracts and commercial products (Sharma et al. 2019 [Ref 7]). All are **indole or oxindole monoterpenoid alkaloids** of the Corynanthe type.

| Alkaloid | PubChem CID | MW | Concentration Range (w/w) | Notes |
|---|---|---|---|---|
| **Mitragynine** | 3034396 | 398.5 g/mol | 0.7–38.7% | Dominant alkaloid; primary active compound |
| **Paynantheine** | 3037629 | 396.5 g/mol | 0.3–12.8% | Second most abundant; weak opioid activity |
| **Speciociliatine** | 15560576 | 398.5 g/mol | 0.4–12.3% | Diastereomer of mitragynine; largely inactive at MOR |
| **Speciogynine** | not confirmed | ~398 | 0.1–5.3% | Minor opioid activity |
| **7-Hydroxymitragynine** | 44301524 | 414.5 g/mol | Trace (<1%) in natural leaf | Potent full MOR agonist; CYP3A4 metabolite of mitragynine; highly concentrated in extracts/semi-synthetic products |

Minor alkaloids also quantified: corynantheidine, corynoxine, corynoxine B, isocorynantheidine (all 0.01–2.8% w/w). **Mitraphylline** was below the lower limit of quantification in all analyzed products (Sharma et al. 2019 [Ref 7]).

### Alkaloid Variability
The wide concentration range for mitragynine (0.7–38.7% w/w) reflects enormous variability across commercial products — a >50-fold difference at the extremes [Ref 7]. Sources of variability include: geographic origin, harvest timing (maturity of leaves), drying method, extraction process, and — critically — commercial adulteration or enrichment. Traditional tea preparations made from leaf material contain significantly lower concentrations of 7-hydroxymitragynine (trace levels) compared to commercially sold extracts and semi-synthetic products, where 7-OH has been chemically enriched or synthesized [Ref 11].

**⚠️ FLAG for human review:** Published data on alkaloid variability by named "vein color" (red vein, green vein, white vein) — a widely used commercial classification system — has **not been confirmed** by peer-reviewed pharmacognosy studies in the reviewed literature. Vein color labeling should be treated as commercial marketing categorization rather than scientifically validated chemotype distinction until published phytochemical studies confirm otherwise.

### Critical Public Health Distinction: Natural vs. Enriched/Semi-Synthetic 7-OH Products
Alsbrook et al. (2025 [Ref 11]) document that while 7-hydroxymitragynine occurs at only trace levels in natural kratom leaf, the US market increasingly offers chemically enriched or semi-synthetic 7-OH products marketed as "kratom." These products are pharmacologically and toxicologically distinct from botanical preparations. This distinction is critical for dose, dependence, and safety characterization (Vadiei, Evoy, Grundmann 2025 [Ref 12]).

### Preparation Methods and Constituent Ratios
- **Dried leaf powder / capsules:** Retains native alkaloid ratio; mitragynine dominant; minimal 7-OH
- **Aqueous tea/decoction (traditional method):** Water-soluble alkaloids preferentially extracted; ratio similar to leaf but per-dose mitragynine varies with leaf quantity and brew time
- **Ethanolic extracts/tinctures:** More complete extraction of alkaloids; higher mitragynine per dose
- **Concentrated extracts ("full-spectrum"):** Mitragynine concentrated; still relatively low 7-OH
- **7-OH enriched products:** Chemically concentrated or semi-synthetic 7-OH; dramatically different pharmacological profile from leaf — potent full MOR agonism, higher respiratory depression risk [Ref 11, 12]

### PubChem Chemical Identity Confirmation
- Mitragynine CID 3034396: C₂₃H₃₀N₂O₄, MW 398.5, InChIKey LELBFTMXCIIKKX-QVRQZEMUSA-N ✓
- 7-Hydroxymitragynine CID 44301524: C₂₃H₃₀N₂O₅, MW 414.5, InChIKey RYENLSMHLCNXJT-CYXFISRXSA-N ✓
- Speciociliatine CID 15560576: C₂₃H₃₀N₂O₄, MW 398.5, InChIKey LELBFTMXCIIKKX-MYLQJJOTSA-N (diastereomer at C-12b) ✓
- Paynantheine CID 3037629: C₂₃H₂₈N₂O₄, MW 396.5, InChIKey JGZKIGWXPPFMRG-CYSPOEIOSA-N ✓

---

## History & Ethnobotany

### First Scientific Description
*Mitragyna speciosa* was first described by the Dutch botanist Pieter Willem Korthals in 1841, during his botanical surveys of the Dutch East Indies (present-day Indonesia and surrounding territories). The genus *Mitragyna* was named for the resemblance of its stipules to a bishop's mitre. The species was later revised by Haviland. Early European documentation of traditional use appears in the work of Low (1836), who documented leaf chewing in Peninsular Malaysia, and subsequently by Ridley (1897) in reports from Singapore [referenced in Cinosi et al. 2015 [Ref 4] and Veltri & Grundmann 2019 [Ref 42]].

### Traditional and Indigenous Use
Kratom (กระท่อม in Thai, *ketum* in Malay) has been used in southern Thailand and the Malay Peninsula for centuries as a **traditional work aid and folk medicine** [Ref 4, Ref 46]. Primary documented uses:

- **Farm and plantation workers** (particularly in southern Thailand and northern Malaysia) chewed fresh kratom leaves daily to combat fatigue, improve work productivity, and sustain energy during manual labor — functioning analogously to coca leaf use in South America [Ref 4]
- **Opium substitute:** As opium became expensive or restricted, kratom served as a less costly alternative in rural communities, particularly for managing physical pain, cough, and diarrhea [Ref 2, Ref 4]
- **Opioid withdrawal management:** By the mid-20th century, kratom was used in traditional contexts to manage opium/opioid withdrawal symptoms [Ref 51]
- **Social lubricant:** Traditional hospitality in some Thai and Malaysian communities involved offering kratom tea to guests, similar to kava in Pacific contexts [Ref 46]

Traditional preparations: fresh leaf chewing (removing the central vein), boiled aqueous decoction (tea/juice), and dried powdered leaf mixed into drinks. One glass of traditional kratom tea contains approximately 19–29 mg mitragynine (derived from Singh et al. 2018 [Ref 45]: 76–115 mg/4 glasses; though exact concentration varies substantially by preparation). **[FLAG: This dose calculation is derived from Singh 2018 and is not directly from a controlled dose quantification study; treat as approximate.]**

### Thai Legal History
Thailand **banned kratom in 1943** under the Kratom Act B.E. 2486 (with formal narcotic scheduling in 1979 under the Narcotics Act placing it in Category 5, alongside cannabis) [Ref 56]. The paradox was widely noted: the government simultaneously profited from opium taxation while banning the cheaper opium alternative. Kratom remained widely used in rural Thai communities despite prohibition. On **August 24, 2021**, Thailand passed Narcotics Act Amendment No. 8 (B.E. 2564), removing kratom from the narcotics list and effectively legalizing it for traditional consumption [Ref 56]. Thailand is now moving toward a regulated commercial kratom sector.

### Malaysian Use Context
Cross-sectional study of northern Malaysian villages (Ahmad & Aziz 2012 [Ref 21]) documented widespread M. speciosa use for psychoactive effects despite legal prohibition under Malaysia's Poison Act 1952. Singh et al. (multiple studies, 2014–2019 [Ref 47, 44, 45, 52, 53]) conducted systematic studies of 150–293 regular kratom users in Malaysia, providing the most detailed published characterization of traditional-context use patterns, dependence, and withdrawal.

### Western Introduction Timeline
- **~2005–2010:** Kratom products begin appearing in Western "head shops" and online markets as a "legal high" and opioid withdrawal aid [Ref 4]
- **2012:** Prozialeck, Jivan, Andurkar publish first widely cited English-language pharmacology review [Ref 2]; Rosenbaum et al. [2012] include kratom in review of herbal alternatives
- **2016:** DEA proposes Schedule I emergency listing (August 31); withdraws after unprecedented public response (142,000+ comments, Oct 13) [Ref 54, 55]; Kruegel & Grundmann review published [Ref 3]
- **2017–present:** Surge in clinical and pharmacological research, driven by interest in kratom for opioid use disorder and pain management in context of opioid crisis

### "Krypton" Product (Important Safety History)
Between 2009 and 2011, a kratom-based herbal product called "Krypton" was sold online and was linked to **9 unintentional deaths in Sweden** [Ref 61]. Forensic analysis revealed the product was kratom leaf powder adulterated with **O-desmethyltramadol** (the active metabolite of tramadol, a potent μ-opioid receptor agonist). The deaths resulted from synergistic dual mu-opioid agonism, not from kratom alkaloids alone [Ref 61]. This event is historically significant as the first documented mass-casualty kratom-related event, and underlines the critical importance of distinguishing pure botanical kratom from adulterated products.

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## Neuroscience & Mechanism

### Primary Receptor Targets

**Mitragynine:**
- **Partial μ-opioid receptor (MOR) agonist** — G-protein biased; does NOT significantly recruit β-arrestin-2 [Ref 3, Ref 6, Ref 25]
- **α₂-adrenergic receptor agonist** — confirmed by binding assays and isobolographic synergy studies (Obeng et al. 2022 [Ref 15])
- **Competitive antagonist at κ- and δ-opioid receptors** [Ref 3]

**7-Hydroxymitragynine (7-OH):**
- **Potent full μ-opioid receptor agonist** — G-protein biased; activity at MOR approximately 13-fold greater than mitragynine, and approximately 46-fold more potent than morphine in some assays [Ref 1, Ref 3]
- Binds MOR only (no significant α₂-adrenergic binding) [Ref 15]
- Produced from mitragynine by CYP3A4 metabolism (both hepatic and intestinal) [Ref 9]

**Significance of G-protein bias (β-arrestin-2 non-recruitment):**
G-protein-biased MOR agonism is proposed to produce analgesia while reducing β-arrestin-2-mediated side effects, including respiratory depression, constipation, and rapid tolerance. Varadi et al. (2016 [Ref 6]) demonstrated that mitragynine pseudoindoxyl (a rearrangement product) showed reduced tolerance development, limited respiratory depression, and no conditioned place preference/aversion in animal models. Henningfield et al. (2017 [Ref 51]) assessed kratom against CSA 8-factor abuse criteria and concluded it has lower respiratory depression and abuse potential compared to classical opioids. However, Henningfield et al. (2022 [Ref 35]) noted in a rodent model that respiratory effects of oral mitragynine vs. oxycodone require careful comparison, and complete absence of respiratory depression has NOT been established — the risk is reduced, not eliminated, particularly with concentrated 7-OH products.

**Additional neurotransmitter systems:**
Kratom alkaloids also interact with serotonergic, dopaminergic, and noradrenergic systems (Green et al. 2025 [Ref 14]). Serotonin release appears to contribute to both analgesia and withdrawal symptoms (Indriani et al. 2025 [Ref 32]). Cognitive effects are attributed to disruption of synaptic plasticity via opioid, serotonergic, and adrenergic receptor interactions (Suhaimi et al. 2025 [Ref 66]).

### Pharmacokinetics (Human Data)

**Trakulsrichai/Wananukul 2015 [Ref 40]** — First and key human pharmacokinetic study; conducted in 10 chronic kratom tea users in Thailand:
- **Route:** Oral (kratom tea)
- **Model:** Two-compartment oral model with linear pharmacokinetics
- **Tmax:** 0.83 ± 0.35 h (~50 min)
- **Terminal half-life:** 23.24 ± 16.07 h (~1 day; range implies high interindividual variability)
- **Volume of distribution (Vd):** 38.04 ± 24.32 L/kg (very large; extensive tissue binding)
- **Urine excretion of unchanged mitragynine:** 0.14% (extensive metabolism)
- **PK linearity confirmed** across dose range tested

**Sempio et al. (2025 [Ref 10])** — Human plasma LC-MS/MS in a clinical trial with 15-day repeated dosing:
- Mitragynine, speciogynine, and speciociliatine accumulate in plasma with daily administration over 15 days (consistent with ~23h half-life)
- 7-OH-mitragynine quantifiable after oral kratom extract

**⚠️ FLAG:** The seed data states "Tolerance half-life: 5 days." Published pharmacokinetic data shows mitragynine *pharmacokinetic* half-life is approximately **23 hours**, not 5 days. If the "5 days" figure refers to *tolerance development/reset* kinetics (not pharmacokinetic half-life), this is community-derived phenomenological data without published clinical confirmation. The generation agent should be aware of this distinction and should NOT present "5 days" as a pharmacokinetic half-life. The 1.5-week full tolerance reset also lacks published confirmation.

### CYP Enzyme Involvement
Kratom is both a **CYP substrate and inhibitor/inducer** — a combination creating significant drug interaction liability:

**As a substrate:**
- Mitragynine is metabolized primarily by **CYP3A4** to 7-hydroxymitragynine; also by CYP2D6
- CYP3A4 inhibitors reduce 7-HMG formation (per PBPK modeling: Chiang et al. 2026 [Ref 37])

**As an inhibitor (in vitro):**
- CYP3A4 inhibition: IC₅₀ 0.78 µg/mL (Kong et al. 2011 [Ref 23])
- CYP2D6 inhibition: IC₅₀ 0.636 µg/mL (Kong et al. 2011 [Ref 23])
- Moderate CYP1A2 inhibition; weak CYP2C19 inhibition (Kong et al. 2011 [Ref 23])
- Time-dependent CYP3A inhibitor: Kᵢ ~4 µM, kᵢₙₐct ~0.07 min⁻¹ (Tanna et al. 2023 [Ref 8])

**As an inducer (via PXR activation):**
- Kratom alkaloids activate PXR (pregnane X receptor) 3–6-fold, inducing CYP3A4, CYP1A2, and P-glycoprotein mRNA expression (Manda et al. 2017 [Ref 22])

**First clinical drug interaction study (Tanna et al. 2023 [Ref 8]):** Single low dose of kratom tea (2 g) in 12 healthy adults:
- Midazolam (CYP3A probe) AUC increased 1.39× (90% CI: 1.23–1.57); Cmax 1.50× — suggests **intestinal CYP3A inhibition**
- Dextromethorphan (CYP2D6 probe): no significant change
- Conclusion: kratom primarily inhibits intestinal CYP3A at typical doses; co-administration with drugs extensively metabolized by CYP3A may precipitate clinically significant interactions

**PBPK modeling (Chiang et al. 2026 [Ref 37]):** Mitragynine increases midazolam exposure 2.2–2.7× with co-administration; CYP2D6 substrates minimally affected.

### Phase II Metabolism
UGT (glucuronosyltransferase) metabolism of kratom alkaloids is poorly characterized (Gunasaykaran et al. 2025 [Ref 28]). This represents a significant knowledge gap for predicting drug interactions involving phase II metabolism.

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## Effects & Dose by Preparation

### Dose-Dependent Biphasic Profile
Kratom is widely described as producing **dose-dependent biphasic effects**: stimulant effects at low doses transitioning to opioid-like sedation and analgesia at higher doses. This characterization originates from traditional SE Asian use accounts and is supported by pharmacological receptor profiling [Ref 2, Ref 3, Ref 4]. However, Singh et al. (2019 [Ref 52]) in a study of 63 regular Malaysian kratom tea users found that **stimulant and sedative effects were not statistically significantly differentiated by dose quantity** (>3 vs ≤3 glasses/day). The biphasic dose-response model is plausible pharmacologically but remains incompletely confirmed in human studies.

### Published Dose Data by Preparation

**⚠️ IMPORTANT FLAG:** No formal dose-finding clinical trials have published quantified dose ranges for named preparations in humans with full pharmacodynamic data as of the research date. The NCT06072170 trial (single ascending doses, completed, Altasciences) has not published full results in accessible form. Dose data below is derived from survey studies and traditional use accounts — not controlled clinical pharmacology. The generation agent should treat these as **unverified dose values requiring human editorial review**.

**Oral leaf powder/capsules (most common Western commercial preparation):**
- Traditional accounts and survey data (Grundmann 2017 [Ref 48]; Smith et al. 2022 [Ref 49]) suggest:
  - Low/threshold: ~1–3 g dried leaf powder
  - Moderate/common: ~3–8 g
  - High/heavy: >8–15 g
- Onset: effects reported to begin within minutes; full onset ~15–30 minutes [Ref 49]
- Peak: ~1–2 hours (consistent with Tmax ~50 min)
- Duration: typically 2–5 hours; effects dissipate within hours [Ref 49]

**Traditional kratom tea/decoction (SE Asian context):**
- Singh et al. (2018 [Ref 45]): 76–115 mg mitragynine per 4 glasses/day used by heavy users; implies ~19–29 mg mitragynine per glass
- Users in Malaysian studies consumed 1–8+ glasses daily [Ref 45]
- Onset: similar to powder; ~15–45 min
- Duration: 3–6 hours (decoction may have slightly different kinetics from powder)

**Concentrated extracts ("kratom shots," 7-OH enriched, semi-synthetic):**
- Pharmacologically distinct from leaf powder; 7-OH content may be orders of magnitude higher
- No published controlled human dose data
- Risk profile substantially different from botanical kratom (Vadiei et al. 2025 [Ref 12]; Alsbrook et al. 2025 [Ref 11])

### Self-Reported Effects by Dose Level
From Smith et al. (2024 EMA study [Ref 50]) and Grundmann 2017 US survey [Ref 48]:

**Low-dose (stimulant range):**
- Increased energy, alertness, and sociability
- Enhanced focus and motivation
- Mild euphoria; mood elevation
- Reduced appetite; stimulation

**High-dose (opioid-like range):**
- Analgesia / pain suppression
- Sedation; drowsiness
- Euphoria (opioid-type)
- Nausea (common adverse effect)
- Constipation
- Pupil constriction (miosis)
- Reduced anxiety

**Adverse effects (dose-dependent):**
- Nausea (very common, particularly at higher doses)
- Constipation
- Dizziness
- Excessive sweating
- Itchiness/pruritus (consistent with MOR agonism)
- Tachycardia at stimulant doses
- Cognitive impairment with chronic use (Suhaimi et al. 2025 [Ref 66])

### Effect Profile Notes on Seed Data (28 Missing Values)
The seed data contains 28 effects all at null/null intensity/frequency. Based on the published literature:
- Perception effects listed (internal hallucinations, dreaming enhancement, visual acuity suppression, etc.) are **not well-supported by published human studies** at typical kratom doses; these appear to be rare/atypical and may reflect very high doses or unusual preparations
- Most robust evidence base is for: stimulation (low dose), sedation (high dose), pain-suppression, nausea, constipation, pupil constriction, cognitive euphoria, anxiety suppression, motivation enhancement, appetite suppression
- **⚠️ FLAG:** The visual, olfactory, and perceptual effects in the seed data should be flagged for editorial review — they are not prominently documented in the controlled or survey literature reviewed

---

## Safety & Toxicity

### LD₅₀ and Toxicology
No published human LD₅₀ data. Animal data: Begum et al. (2024 [Ref 13]) reviewed in vitro and in vivo toxicity studies documenting hepatic, renal, pulmonary, and CNS toxic effects in rodent models at high doses. Acute human toxicity is considered **low at typical traditional doses** (consistent with seed data: acute toxicity: low), but **chronic toxicity data are limited and concerning** for liver, kidney, and cognitive function [Ref 13].

### Hepatotoxicity (Critical Safety Issue)
Kratom is a **documented cause of drug-induced liver injury (DILI)**, predominantly with a **cholestatic pattern**:

Schimmel & Dart (2020 [Ref 30]) comprehensive review:
- 26 published case reports + 7 DILI Network cases + 25 FDA database cases + 27 internet forum reports
- Median latency to symptom onset: **20.6 days** (mean 21 days; range 2–49 days)
- Common symptoms: abdominal discomfort, **jaundice**, pruritus, dark urine
- Histological pattern: predominantly **cholestatic**; biochemically heterogeneous or mixed (median R ratio 3.4)
- RUCAM causality assessment: kratom "likely causes liver injury based on totality of evidence"
- At-risk subgroups not yet identified

Individual case reports:
- Kapp et al. (2011 [Ref 43]): Intrahepatic cholestasis following powdered kratom abuse — one of the earliest and most cited reports
- Gandhi et al. (2020 [Ref 29]): Kratom-induced severe cholestatic liver injury histologically mimicking primary biliary cholangitis

### Fatal Cases and Respiratory/Cardiovascular Toxicity
**Krypton deaths (Sweden, 2011 [Ref 61]):** 9 fatalities from kratom leaf powder adulterated with O-desmethyltramadol (active tramadol metabolite). Mitragynine blood: 0.02–0.18 µg/g; O-DMT blood: 0.4–4.3 µg/g. Deaths attributed to **dual mu-opioid agonism from the combination**, not kratom alone. Critical adulteration context.

**Fatal overdose — hydromorphone + kratom [Ref 19]:** 44-year-old male found deceased; femoral blood: 79 ng/mL hydromorphone, 560 ng/mL mitragynine, 240 ng/mL olanzapine. Death attributed to hydromorphone toxicity with mitragynine as **contributing factor**. Renal impairment present.

**Cardiorespiratory fatality — suspected kratom alone [Ref 20]:** 26-year-old male in cardiorespiratory arrest 24h after kratom use; died from cardiorespiratory failure and hypoxic brain damage despite multi-organ support. Intralipid showed temporary improvement. Pre-existing conditions and polydrug exposure not fully excluded.

**Population-level data (Veltri & Grundmann 2019 [Ref 42]):** Deaths attributed to kratom use in Europe and the US, but **causality could not be established** in almost all cases due to poly-drug exposures. No deaths attributed to kratom alone in SE Asia in published literature reviewed.

### Psychological and Cognitive Risks
- Kratom use may adversely affect cognitive performance through disruption of synaptic plasticity and brain activity (Suhaimi et al. 2025 [Ref 38])
- Epigenetic mechanisms implicated in withdrawal-associated cognitive impairment (Yunusa et al. 2024 [Ref 27])
- Psychiatric adverse effects at high doses: anxiety, irritability, psychosis reported in concentrated 7-OH withdrawal case (Sharma et al. 2025 [Ref 17])
- **Cannabis-like or opioid-like addictive potential:** Kratom has been associated with compulsive use patterns meeting DSM-5 SUD criteria (Rogers et al. 2024 [Ref 16])

### Herb–Drug Interactions
**Mechanism-based interactions (strongest evidence):**

| Interaction | Mechanism | Evidence Level |
|---|---|---|
| **CYP3A substrates** (midazolam, cyclosporine, many opioids, many statins) | Intestinal CYP3A inhibition by mitragynine | Clinical study (Tanna 2023 [Ref 8]); PBPK model (Chiang 2026 [Ref 37]) |
| **CYP2D6 substrates** (codeine, tramadol, many antidepressants) | In vitro CYP2D6 inhibition | In vitro only (Kong 2011 [Ref 23]); clinical study showed no effect at 2g dose [Ref 8] |
| **CYP3A4, CYP1A2, P-gp substrates** (via PXR induction) | PXR-mediated enzyme induction with repeated use | In vitro/cell-based (Manda 2017 [Ref 22]) |
| **Other opioids** (additive/synergistic CNS/respiratory depression) | Pharmacodynamic synergy at MOR | Case reports of fatalities [Ref 19, 61] |
| **CNS depressants** (benzodiazepines, alcohol, GHB/GBL, sedatives) | Pharmacodynamic CNS depression synergy | Mechanistic plausibility; limited clinical case data |

**⚠️ FLAG — Seed Data Interaction Severities:**
The seed data lists several interactions as "lethal." Assessment against published evidence:

- **Tramadol: lethal** — CONFIRMED in context of adulteration: the Krypton deaths (9 fatalities) involved kratom + O-desmethyltramadol, the active tramadol metabolite [Ref 61]. The "lethal" rating is appropriate but should be contextualized: (1) the Krypton deaths involved an adulterant, not tramadol prescribed at therapeutic doses + kratom; (2) kratom + tramadol at normal doses may also be dangerous due to serotonin syndrome risk (tramadol is also a serotonin reuptake inhibitor; combining with kratom's serotonergic activity is potentially hazardous) but a clinical case report of this specific mechanism was not identified in reviewed literature.

- **Alcohol: lethal** — CNS depressant synergy is pharmacodynamically plausible; however, **no published clinical case report of kratom + alcohol fatality with established causation was identified** in the reviewed literature. Flag as mechanistically plausible but evidence level is "pharmacodynamic" not case-confirmed.

- **GBL: lethal, GHB: lethal** — CNS depressant + opioid-like combination; pharmacodynamically plausible (GHB/GBL have GABAergic and opioid-like effects and respiratory depression risk). **No published clinical case report of kratom + GHB/GBL fatality was identified.** Flag for human editorial review.

- **Ketamine: lethal** — Pharmacodynamically plausible (combined CNS depression, respiratory risk). **No published clinical case report identified.** Flag.

- **Nitrous: unknown, PCP: unknown** — Consistent with literature absence.

### Tolerance Development and Cross-Tolerance
Tolerance develops with **prolonged and repeated use** (seed data: confirmed). Cross-tolerance with opioids is documented (seed data confirmed) — given MOR partial agonism. Clinical note: buprenorphine can precipitate withdrawal in kratom-dependent patients, suggesting clinically significant opioid cross-tolerance (Sharma et al. 2025 [Ref 17]).

The seed data states tolerance half-life of 5 days and full reset at 1.5 weeks. **⚠️ FLAG:** These values are not confirmed in any published clinical study reviewed. Given mitragynine's ~23-hour pharmacokinetic half-life, tolerance should reset more rapidly than opioids with longer half-lives, but specific tolerance recovery timelines need published validation. Treat as community-derived estimates.

### Dependence Liability and Withdrawal
**Physical dependence:** High (seed data confirmed), with opioid-like withdrawal syndrome. First systematic characterization by Singh, Muller, Vicknasingam (2014 [Ref 47]).

**Withdrawal syndrome (Singh et al. 2018 [Ref 44, 45]; ~150–170 Malaysian regular users):**
- **Psychological:** 70% mild anxiety, 81% mild depression; higher doses (≥4 glasses/day) associated with more severe depression
- **Physical:** 84% moderate pain intensity, 70% moderate pain interference, 46% sleep problems
- **Severity context:** "Relatively mild" compared to opioid analgesic withdrawal; cessation not associated with prolonged severe pain or sleep problems [Ref 45]
- **Dose-dependence:** Higher daily dose = more severe withdrawal [Ref 44, 45]

**Additional withdrawal symptoms reported in case reports:** Insomnia, myalgia, anxiety, diaphoresis, gastrointestinal upset, agitation, irritability, restlessness, concentration difficulty [Ref 17]. Severe cases with concentrated 7-OH products: psychosis, respiratory compromise requiring intubation [Ref 17].

**Withdrawal onset:** Given ~23-hour half-life, would be expected to begin within 12–24 hours of last use. **Specific onset timeline not confirmed in published literature** — flag.

**Treatment approaches documented:**
- **Buprenorphine** (low-dose sublingual): complete abstinence in 3 weeks in case report [Ref 18]; BUT can precipitate withdrawal if patient is opioid-tolerant [Ref 17]
- **Dihydrocodeine** and **clonidine**: mentioned in case series context
- **Supportive care**: for mild-moderate withdrawal in traditional context
- **Phenobarbital/benzodiazepines**: used when co-occurring GABAergic withdrawal present (Bleifuss et al. 2025 [Ref 40-series])

**DSM-5 SUD application:** Rogers et al. (2024 [Ref 16]) applied DSM-5 criteria and confirmed kratom can meet SUD criteria; dose frequency showed stronger association with dependence indicators than dose amount.

### Contaminant and Adulterant Risk
**Critical safety concern for commercial products:**
- **O-desmethyltramadol:** documented in "Krypton" products; 9 deaths [Ref 61]
- **Salmonella contamination:** FDA Import Alert 54-15 cites contamination risks; FDA seized products and issued public warnings (no specific published peer-reviewed study identified in search; web-retrieved FDA sources [Ref 58])
- **Heavy metals** (lead, cadmium): possible in dried botanical products; specific validated studies not identified in PubMed search
- **Labeling inaccuracy:** Wide concentration ranges (0.7–38.7% mitragynine w/w) across commercial products suggest significant batch-to-batch and product-to-product variability [Ref 7]
- **Unenriched vs enriched products:** Semi-synthetic 7-OH products marketed as "kratom" [Ref 11] represent a distinct adulterant/adulteration concern

**⚠️ FLAG:** Specific published peer-reviewed data on heavy metal contamination and Salmonella contamination of commercial kratom products was not found in PubMed search. This is a known FDA concern documented in import alerts (web-retrieved only [Ref 58]).

### Vulnerable Populations

**Pregnancy:**
- **Neonatal abstinence syndrome (NAS)** documented with kratom use in pregnancy (Chomchai et al. 2019 [Ref 65])
- Kratom use during pregnancy reviewed by Faucher et al. (2024 [Ref 33]): evidence is limited to case reports; significant concern given opioid-like properties; unknown teratogenicity
- **⚠️ FLAG:** Contraindicated in pregnancy based on opioid-like mechanism and NAS risk; evidence is case-report level only

**Psychiatric conditions:**
- Kratom used to self-medicate anxiety, depression, OCD (Teixeira et al. 2025 [Ref 18])
- Risk of worsening cognitive function and psychiatric outcomes with heavy/chronic use [Ref 38]

**Hepatic impairment:**
- Kratom causes and may worsen hepatic injury; contraindicated [Ref 30]

---

## Harm Reduction

### Published Risk Reduction Strategies
Based on reviewed literature (Veltri & Grundmann 2019 [Ref 42]; Eastlack et al. 2020 [Ref 41]; Emerick et al. 2024 [Ref 34]):

1. **Avoid concurrent use with opioids, CNS depressants, alcohol, GHB/GBL**: Pharmacodynamic synergy risk; multiple fatal cases in polydrug context
2. **Avoid enriched/semi-synthetic 7-OH products**: Dramatically different risk profile from botanical kratom leaf preparations [Ref 11, 12]
3. **Avoid concurrent CYP3A substrates with narrow therapeutic index**: Kratom inhibits intestinal CYP3A [Ref 8]
4. **Avoid concurrent tramadol**: Risk of adulteration with O-desmethyltramadol and direct pharmacodynamic MOR agonism interaction [Ref 61]
5. **Monitor for liver injury symptoms**: Jaundice, dark urine, pruritus, abdominal discomfort — seek medical attention; median latency ~3 weeks [Ref 30]
6. **Purchase from GMP-compliant suppliers**: To reduce contamination and labeling accuracy risks
7. **Kratom Consumer Protection Act (KCPA) compliance**: Some US states (and Rhode Island from April 2026) have implemented labeling, testing, and age restrictions under KCPA frameworks

### Testing and Identification
- Kratom alkaloids are **NOT detected by standard immunoassay drug screens** (including standard opioid immunoassays) [Ref 31]
- Detection requires specific LC-MS/MS or GC-MS methods
- No commercially available kratom-specific rapid test validated for consumer use was identified in the reviewed literature

### Cessation and Recovery
- Withdrawal is generally manageable without medical intervention for leaf-based kratom at moderate doses [Ref 45]
- Medical support recommended for heavy/concentrated product use or concurrent opioid dependence
- Buprenorphine effective in documented cases [Ref 18]; precipitated withdrawal risk in opioid-tolerant patients [Ref 17]
- Use-frequency (rather than dose amount) shows stronger association with dependence severity — suggests that frequency reduction may be a key harm reduction strategy [Ref 16]

### Emergency Response
- Opioid overdose reversal with naloxone: standard approach given MOR agonism; may require higher doses due to large Vd and partial agonism profile
- Intralipid reported as providing temporary improvement in one kratom-associated cardiorespiratory arrest [Ref 20]
- ICU-level support for severe cases

---

## Legal Status

### United States — Federal
Kratom (and its primary alkaloids mitragynine and 7-hydroxymitragynine) is **currently federally unscheduled** under the Controlled Substances Act [Ref 54, 55, 59].

**DEA history:**
- **August 31, 2016:** DEA published notice of intent in Federal Register to temporarily place mitragynine and 7-hydroxymitragynine into **Schedule I** on an emergency basis (citing imminent hazard to public safety) [Ref 55]
- **October 13, 2016:** DEA **withdrew** the notice — the first time in DEA history an emergency scheduling notice was withdrawn. The public comment period generated approximately **142,000 comments** (the largest in DEA history), the overwhelming majority opposing scheduling [Ref 54]
- DEA continues to list kratom on its "Drugs and Chemicals of Concern" list

**FDA regulatory position [Ref 58]:**
- Kratom is **not lawfully marketed** as a drug product, a dietary supplement, or a food additive in conventional food
- FDA Import Alert 54-15 (active; most recent update July 2023): authorizes detention of imported kratom products without physical examination from listed firms
- April 2023: FDA seized ~$3M worth of kratom products from an Oklahoma company
- 2025: FDA issued warning letters specifically targeting **7-hydroxymitragynine enriched products**, citing respiratory depression, seizures, liver toxicity, and fatalities

### United States — State Level [Ref 59]
States with **complete bans** (as of May 2026):
- **Alabama** (2016) — mitragynine and 7-OH listed as Schedule I
- **Arkansas** (2016) — Schedule VI
- **Indiana** (2014) — Schedule I; one of the earliest state bans
- **Vermont** — banned
- **Wisconsin** — Schedule I

**Rhode Island:** Historically banned; **signed Kratom Consumer Protection Act (KCPA) July 2025**, effective April 1, 2026 — transitioning from ban to regulated framework [Ref 59].

**Kratom Consumer Protection Act (KCPA) states:** Several states have enacted KCPA-style regulations (age restrictions, labeling requirements, testing standards) rather than outright bans.

**⚠️ FLAG:** State-level kratom legislation is rapidly evolving. This data reflects the state as of research date (May 2026); the generation agent should note that this section has a high likelihood of being outdated and recommend editorial verification.

### International

**Thailand [Ref 56]:**
- Banned under Kratom Act B.E. 2486 (1943) and formally under Narcotics Act Category 5 (1979)
- **Legalized August 24, 2021** under Narcotics Act Amendment No. 8 (B.E. 2564); consumption, production, possession now legal in any amount; ~121 inmates with kratom-only convictions released

**Malaysia:**
- Illegal under Poison Act 1952; possession and sale prohibited

**Australia [Ref 63]:**
- **Schedule 9 (Prohibited Substance)** under the Poisons Standard (SUSMP) since 2003 — same category as heroin and MDMA
- Illegal to possess, sell, or distribute for human consumption; approved research is the only exception

**United Kingdom [Ref 63]:**
- Illegal since **May 2016** under the Psychoactive Substances Act 2016, which broadly bans psychoactive substances; importation, sale, and supply prohibited

**European Union (selected countries) [Ref 63]:**
- **Netherlands:** Legal; major European retail market (licensed smartshops)
- **Sweden:** Banned since 2011
- **France:** Banned since 2020
- **Poland:** Banned as a narcotic substance
- **Denmark:** Banned without prescription
- **Romania:** Banned since 2023
- **Germany:** Unscheduled federally; individual state regulations may vary

**WHO international scheduling [Ref 62]:**
- 2021 WHO Expert Committee on Drug Dependence (ECDD) conducted a **critical review** and found **insufficient evidence to recommend international scheduling** of kratom under the 1961, 1971, or 1988 UN drug conventions. This decision reduced pressure on member states to ban the substance.

### Treaty Status
The primary kratom alkaloids (mitragynine, 7-hydroxymitragynine) are **not listed** under the three major UN drug control treaties (1961 Single Convention, 1971 Convention on Psychotropic Substances, 1988 Trafficking Convention) as of research date. This accounts for the patchwork of national regulations rather than internationally harmonized control.

---

## Clinical Trials

| NCT ID | Title | Status | Phase | Condition | Sponsor |
|---|---|---|---|---|---|
| NCT04392011 | Assessing the Pharmacokinetics and Drug Interaction Liability of Kratom | Completed | Early Phase 1 | Drug-food interaction | Washington State University |
| NCT06072170 | Single Ascending Doses of Kratom in Healthy Nondependent Adults With Opioid Experience | Completed | Phase 1 | Safety, PK, PD | Altasciences Company Inc. |
| NCT05457803 | Real-World Momentary Assessment of Kratom Use (NIDA natural history study) | Completed | N/A | Chronic pain, fatigue, SUD | NIDA |
| NCT05846451 | Evaluating a Potential PK Kratom-Oxycodone Interaction With Clinical Endpoints | Recruiting | Early Phase 1 | Herbal interaction | Washington State University |
| NCT07204171 | Phase 1 Study of Oral MG001 (pure mitragynine) | Not Yet Recruiting | Phase 1 | Safety/tolerability in healthy subjects | NIDA |

Note: NCT06072170 (Altasciences, completed Phase 1 single ascending dose study) is of particular importance — it is the first controlled human dose escalation study of botanical kratom, but results have not yet been published in a peer-reviewed journal as of the research date.

---

## Community Feedback Analysis

No community feedback was submitted in Part A2 of the brief.

---

## Gaps & Flags

### 🔴 CRITICAL FLAGS (requiring human editorial review before publication)

1. **Type field:** Seed data lists Type as "preparation" — should be "plant." Kratom is a plant; kratom powder/tea/extracts are preparations. Flag for database correction.

2. **Tolerance half-life "5 days":** Published pharmacokinetic half-life of mitragynine is ~23 hours, NOT 5 days (Trakulsrichai 2015 [Ref 40]). If "5 days" refers to tolerance reset kinetics (not pharmacokinetic half-life), this is unverified community-derived data. The generation agent must NOT present this as a pharmacokinetic half-life value.

3. **Dose values:** No published controlled human dose-finding study results were available for this research. All dose data is derived from surveys, traditional use accounts, or extrapolation from alkaloid content of preparations. **Treat all dose range values as unverified.**

4. **Withdrawal onset timeline:** Not published in clinical studies. The seed data has no withdrawal timeline — this gap should be clearly stated, not filled with unverified values.

5. **Herb–drug interactions "lethal" severity ratings:**
   - Tramadol: Confirmed lethal via adulteration (Krypton/O-desmethyltramadol [Ref 61]); NOT a clinical case of prescribed tramadol + kratom. Severity appropriate but mechanism context required.
   - Alcohol: No published case-confirmed fatality found. Flag as pharmacodynamic plausibility only.
   - GBL/GHB: No published case-confirmed fatality found. Flag as pharmacodynamic plausibility only.
   - Ketamine: No published case-confirmed fatality found. Flag as pharmacodynamic plausibility only.
   - All four: require human editorial assessment of whether "lethal" severity label is appropriate without case confirmation.

6. **Visual and perceptual effects:** 6 of the 28 seed effects relate to visual/perceptual phenomena (internal hallucinations, dreaming enhancement, visual acuity suppression, visual processing suppression, olfactory hallucination, music enhancement). These are **not prominently documented** in the pharmacological or survey literature at typical kratom doses. Flag for editorial review — they may reflect high-dose or idiosyncratic experiences rather than common effects.

7. **Seed data "Characterization: emerging":** Given the extensive published literature (hundreds of peer-reviewed papers), kratom appears to be more than "emerging" in terms of pharmacological characterization. The characterization may reflect the regulatory/clinical development status rather than literature maturity. Editorial clarification warranted.

### 🟡 NOTABLE GAPS (data absent from published literature)

8. **Heavy metal and Salmonella contamination:** FDA enforcement actions reference contamination risk, but specific published peer-reviewed contamination surveys were not found in PubMed search. Web-retrieved FDA sources only.

9. **Kratom drug testing:** Standard immunoassay panels do not detect kratom alkaloids. Specific LC-MS/MS methods exist (clinical/forensic) but no validated commercial rapid test identified.

10. **Alkaloid variability by "vein color":** The commercial vein color classification (red/green/white) is not validated by published phytochemistry as a reliable chemotype indicator.

11. **UGT phase II metabolism:** Data sparse; significant knowledge gap for drug interaction prediction.

12. **Mitragynine bioavailability:** Published human PK data exists but % bioavailability (fraction absorbed) not directly measured; animal studies available.

13. **Effects in controlled human studies:** Most effects data is from self-report surveys, not controlled clinical pharmacology. The NCT06072170 trial results (Altasciences) would be the key dataset to fill this gap when published.

14. **Long-term safety data:** Chronic toxicity in humans (beyond case reports of hepatotoxicity) is largely uncharacterized.

15. **Sex differences:** PBPK modeling suggests sex-related PK differences (Chiang et al. 2026 [Ref 37]); not yet characterized in human subjects.

16. **Plant cultivation status:** POWO does not specify cultivation status; commercial cultivation in Indonesia (Borneo) is documented in literature context but no systematic cultivation study found.