How long does Kratom (Mitragyna speciosa) stay in the system?

How Long Does Kratom Stay in the System?

Kratom's primary alkaloids (mitragynine and 7-hydroxymitragynine) produce acute effects lasting 2-3 hours, with systemic detection possible up to 8 hours post-dose in animal studies, though human detection windows remain poorly characterized due to limited research. 1, 2

Acute Effects Duration

The clinical effects of kratom follow a relatively short time course:

• Onset of effects: Begins within minutes of oral consumption 3
• Peak effects: Occur within 40 minutes, reaching maximum intensity around 72.7/100 on subjective scales 4
• Duration of subjective effects: Effects remain above baseline for 80-120 minutes (approximately 1.3-2 hours) 4
• Complete dissipation: Acute effects typically resolve within hours of consumption 3

Pharmacokinetic Data from Animal Studies

The most detailed pharmacokinetic information comes from rat studies, which provide insight into systemic exposure:

• Detectable alkaloids at 8 hours: Only mitragynine, 7-hydroxymitragynine, speciociliatine, and corynantheidine showed systemic exposure 8 hours post-dose 2
• Short-lived minor alkaloids: Paynantheine and speciogynine were quantifiable only up to 1 hour post-dose 2
• Other alkaloids: Corynoxine, corynoxine-B, mitraphylline, ajmalicine, and isospeciofoline were not detected in plasma samples 2

Clinical Observations in Regular Users

Direct observation studies in humans who use kratom regularly reveal:

• Pupil constriction: Decreased pupil diameter occurs 40-80 minutes post-dose and remains below baseline for more than 160 minutes, suggesting opioid-like effects persist beyond subjective awareness 4
• Physiological changes: Most vital sign changes are minor and transient 4
• Withdrawal timeline: Mild withdrawal symptoms (mean 5.5 on Subjective Opioid Withdrawal Scale) decrease significantly post-dosing among regular users 4

Critical Gaps in Detection Knowledge

There is no established urine or blood detection window for kratom alkaloids in humans, and standard drug-screening panels do not include kratom. 1

Important Caveats:

• Testing limitations: Unlike prescription opioids (detectable 1-2 days) or cannabis (detectable 1-30 days depending on use pattern), kratom requires specialized testing that is not routinely available 1
• No standardized screening: Healthcare providers must specifically request kratom/mitragynine testing, as it will not appear on standard toxicology panels 1
• Individual variability: The Society for Perioperative Assessment and Quality Improvement (SPAQI) recommends discontinuing kratom before surgery due to opioid-like properties and potential withdrawal syndrome, but provides no specific detection window 1

Practical Clinical Implications

For perioperative management:

• SPAQI recommendation: Discontinue kratom use entirely before surgery, particularly for those consuming >5-15 g per day who may experience withdrawal 1
• Withdrawal risk: Greater severity of unwanted effects from ≥1 day of kratom cessation correlates with more weeks of regular use 3
• Chronic use effects: Neurologic effects including seizures may occur with chronic use, though the timeframe for clearance of these risks is unknown 1

Bottom Line for Clinical Practice

The lack of human pharmacokinetic studies and validated detection methods means clinicians must rely on patient self-report and clinical observation. If kratom use is suspected or disclosed, assume effects may persist for several hours acutely, but plan for potential withdrawal symptoms in regular users who abstain for even one day. 3, 4 Specialized laboratory testing must be specifically requested and may not be readily available in most clinical settings. 1