A Southeast Asian leaf whose compounds act partly like opioids and partly like stimulants, with dose deciding which. Less pain, more energy and steadier mood are consistently described but barely measured. The costs are better established: dependence with withdrawal on stopping, nausea and constipation, uncommon but occasionally severe liver injury. Nearly every death involved other depressant substances. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Alanine aminotransferase | Under 25 U/L men, 20 U/L women | Cell-injury component of liver toxicity |
| Alkaline phosphatase with total bilirubin | 40–90 U/L; bilirubin under 1.0 mg/dL | The cholestatic pattern kratom injury takes |
| Gamma-glutamyl transferase | Under 20 U/L men, 15 U/L women | Bile-duct versus bone cause of a raised alkaline phosphatase |
| LDL-C | Under 2.6 mmol/L (100 mg/dL) | Whether the cohort-level metabolic difference appears individually |
| Resting heart rate and blood pressure | 50–70 per minute; under 120/80 mmHg | The commonest cardiovascular effects |
| Corrected QT interval (electrocardiogram) | Under 450 ms men, 460 ms women | Mitragynine lengthens electrical recovery time, dose-dependently |
| Prolactin and total testosterone (men) | Prolactin under 15 ng/mL; testosterone 600–900 ng/dL | Opioid activity can suppress the hormonal axis |
| Creatinine with estimated glomerular filtration rate | Above 90 mL/min/1.73 m² | Kidney reserve, clearance, heavy-metal exposure |
Cadence: Baseline panel before any use; liver enzymes and bilirubin at 6 weeks; blood pressure and heart rate at 4 weeks; full repeat panel with lipids and electrocardiogram at 6 months, then every 6 to 12 months while use continues. Jaundice, dark urine or itching triggers immediate testing.