How Long Does Kratom Stay in Your System?

While kratom has only recently gained attention in Western countries, it has a long history of use in the countries where the Mitragyna speciosa tree (the “kratom tree”) grows, such as Thailand, Malaysia, and Indonesia. Kratom has been used for centuries to treat various medical ailments and as part of socioreligious ceremonies.²

At low doses, kratom produces a mild stimulant effect, which propelled its use among farm workers in Southeast Asia who needed to fight off fatigue and stay productive over long hours.²

At higher doses, kratom produces sedating, opioid-like effects, and for this reason, some people use the drug to try to self-medicate pain or lessen their opioid withdrawal symptoms.⁴

According to the Drug Enforcement Administration, kratom use has been linked to various adverse medical and psychiatric events, including:³

• Increases in heart rate.
• Nausea.
• Seizures.
• Hallucinations.
• Psychosis.

However, the drug is not a controlled substance (barring some states that have instituted legal restrictions on the substance, it remains available to purchase and use throughout much of the country), and many people tout the drug’s potential benefits, often implying that the drug is a safe, natural, and easier-to-obtain alternative to other opioid replacement therapies such as methadone.

Kratom retailers often market their products as natural remedies or dietary supplements, leading buyers to believe there are few, if any, risks to consuming kratom. A significant increase in kratom-related poison control center calls in a 5-year period, however, suggests otherwise, and the U.S. Food and Drug Administration cautions people not to use kratom-containing products.¹

Much still needs to be learned about the pharmacology of kratom. What research exists suggests that kratom may have some antidepressant effects, as well as analgesic (pain-relieving) and anti-inflammatory properties,² but kratom’s opioid properties, its potential for abuse, its reported side effects, and a number of deaths associated with the substance has prompted the FDA to place an import alert on kratom and the DEA to list it as a Drug and Chemical of Concern.

Additionally, several states have already banned the drug.^1,3 What should be a major concern for kratom buyers is the fact that the drug is unregulated, meaning it would be all too easy for a disreputable supplier to lace its product with unreported, potentially-harmful substances.

How Long Does Kratom Remain in Your System?

Elimination half-life is a term used to describe the time it takes for the drug’s plasma concentration to be reduced by half.⁵ The drug is proportionally eliminated from the body with each additional half-life.⁶ For example, if a 100 mg dose of an intravenous drug with a half-life of 15 minutes was given to a patient, it would take 15 minutes for 50 mg of the drug to remain in the system; it would take 30 minutes for 25 mg to remain; 45 minutes for 12.5 mg to remain; 120 minutes for 0.39 mg to remain; and so on.⁶

In the case of a substance like kratom, pharmacologic studies are ongoing and there are some differences in terms of reported half-life measurements. For example, one study found the elimination half-life for mitragynine to be approximately 3.85 hours (±0.51 hours). This means it would take nearly 4 hours for the plasma concentration to be reduced by just half.⁷ Another study found the half-life to be somewhat longer at 9.43 hours (±1.74 hours).⁸ With half-life measurements in that ballpark range, the alkaloid may still be detected in the plasma after 24 hours.

Some online articles have cited the elimination half-life of mitragynine to be nearly 24 hours, due to yet another study that found the terminal half-life to be 23.24 hours (±16.07 hours).⁷ However, the terminal half-life is a different measurement than elimination half-life. Terminal half-life is the time it takes for the plasma concentration of a substance to be divided by 2 after reaching pseudo-equilibrium. Terminal half-life does not reflect the rate of elimination but rather how quickly and how much the drug is absorbed.⁹

The elimination half-life of mitragynine may be somewhat affected by the method of use. In one study, the average half-life after injection was 2.9 hours (±2.1 hours). However, after oral ingestion, the elimination half-life was 6.6 hours (±1.3 hours).⁸

Mitragynine can be detected in urine screens.⁸ While kratom users may try to determine how long kratom stays in their systems to avoid a positive drug screen, it’s important to remember that there are a multitude of variables that determine just how long a substance like kratom will be detected in the body (such as method of use, health, and age) and avoiding a positive test isn’t as simple as making a calculation based on the elimination half-life. In fact, even the age of the plant, the environment in which the plant grew, and the time of harvest can impact how much of the mitragynine alkaloid is in the plant.⁸

Key Things to Know

The overall takeaways can be summed up briefly:

• Kratom can be consumed as a tea, through pills, and by chewing the leaves.
• Dependence on the drug can develop and may lead to withdrawal symptoms, such as insomnia or achy muscles, if the user attempts to stop consuming the drug.
• Finally, how long Kratom remains in the user’s system is determined by a number of factors, which means that a definitive response to the question cannot be given.