Kratom: Potential risks and side effects

While some users report mild benefits, research and case reports highlight a range of potential kratom side effects and health risks. Understanding these is crucial for anyone considering using this plant, either infrequently or regularly.

Overall, kratom’s unique effects are dose-dependent, strain-specific, and influenced by the physiology of individual users. The phytochemicals found in the plant interact with multiple systems in the body, adding a deep complexity to its safety profile.

What Is Kratom and Why Do People Use It?

Kratom, also known by its Latin binomial name Mitragyna speciosa, is a tropical tree native to Southeast Asia. Its leaves are a reservoir of natural chemicals and contain over 50 alkaloids, with mitragynine and 7-hydroxymitragynine being the most biologically active and well-known among users. Traditionally, the plant is used by labourers for energy and endurance, as well as in ceremonial contexts.

In the modern era, kratom is often marketed as a supplement for pain relief, mood enhancement, or opioid withdrawal support. This has made it a highly controversial topic, with some users espousing potential benefits, while health authorities remain sceptical and concerned about safety and long-term risks.¹ For a broader overview, see kratom uses, effects, and considerations.

Various forms of kratom are available on the market, including powder, capsules, teas, and extracts, with potency and alkaloid content varying widely. If you’re comparing formats, this guide to how to take kratom outlines common methods.

Is Kratom Classed as a Drug by Health Authorities?

Globally, kratom occupies a grey area when it comes to prohibition. In the United States, the FDA has not approved kratom for any medical use and has issued warnings about potential safety risks. Other countries have either regulated kratom or have completely banned it as a psychoactive drug (including the UK), while some nations allow traditional use.²

For instance, Thailand recently decriminalised kratom for traditional use, whereas countries like Australia and Denmark classify it as a controlled substance. These differences affect how it is researched and marketed, with prohibition making it harder for scientists to study in some regions.

Does Kratom Show Up on a Drug Test?

Most drug tests do not screen for the active compounds found in kratom, especially compared to more commonly used compounds such as THC. However, specialised tests can measure levels of both mitragynine and 7-hydroxymitragynine in blood and urine.

The window in which these compounds remain detectable hinges on several variables, including the dose used, how often a person uses kratom, and their individual metabolism. While the occasional use of low doses may become undetectable after 25–48 hours, frequent consumption of stronger strains may trigger a positive test several days later.

Common Side Effects of Kratom Use

Like all drugs, the active constituents of kratom can produce several side effects in some users, from mild discomfort to more serious complications. The seriousness of side effects a person may experience also depends on factors such as the dosage taken, how often they use kratom, and if they take the plant alongside other substances.³

Mild to Moderate Side Effects

While uncomfortable, the mild to moderate side effects of kratom are less serious than more severe complications. They include:

• Nausea and vomiting
• Constipation or gastrointestinal discomfort
• Dry mouth
• Dizziness and lightheadedness
• Mild sedation or overstimulation

Although more common, the mild side effects of kratom don’t stop with the list above. Some users also experience headaches, sweating, increased urination, and temporary loss of appetite. Slight fluctuations in blood pressure or heart rate are also possible.

These symptoms are less likely to manifest at lower doses, highlighting the importance of slowly and gently introducing kratom and exercising moderation at all times when using the plant for all purposes. For practical ranges, review how to dose kratom safely.

Severe or Long-Term Side Effects

Both severe and long-term side effects associated with kratom are uncertain, and usually occur following excess consumption both acutely and over time. These serious complications include:

• Liver toxicity: Elevated liver enzymes and acute liver injury have been observed, particularly with chronic or high-dose use.⁴
• Seizures: High doses may increase seizure risk, especially in individuals with pre-existing neurological conditions.
• Memory and cognitive issues: Prolonged high-dose use can impair attention, working memory, and executive function.

The lack of human studies surrounding kratom and the ethical problems with long-term trials mean other possible long-term effects haven’t yet been identified. However, other chronic complications include hormonal imbalance, cardiovascular issues, and changes in skin pigmentation.

Psychological Impacts

Aside from the plant’s effect on the body, kratom use can also impact the mind. While it allows users to experience either stimulation or relaxation in the short term, high doses or prolonged use can have adverse effects on mental health and cognition. These symptoms include:

• Anxiety or agitation
• Irritability
• Confusion or disorientation
• Rarely, hallucinations or psychotic symptoms

Some evidence also suggests that frequently taking high doses of kratom could cause depressive symptoms, impact motivation, and predispose people to stress.⁵ Those with a history of mental health issues are more likely to encounter these serious psychological side effects.

Kratom may also influence sleep. Some users report struggling to maintain deep and uninterrupted sleep when taking kratom frequently, which has a knock-on effect leading to fatigue and reduced cognitive performance.

Kratom Dependency and Withdrawal Symptoms

Kratom can cause dependency in some users, especially those who take the plant in high doses for long periods. This pattern of consumption can then lead to withdrawal symptoms following cessation. Although typically less severe than withdrawals tied to opioid use, kratom withdrawal symptoms can be distressing and include:

• Muscle aches and cramps
• Insomnia and fatigue
• Anxiety or irritability
• Low mood or depression

In most frequent users, these withdrawal symptoms typically start 12–48 hours after the last dose and may linger for several days.

As with most cases of withdrawal, the symptoms are usually more intense in users who have built up a tolerance to the active chemicals in kratom and are therefore often taking very high doses to feel the effects. In such instances, gradual reduction of the dosage under medical supervision may be necessary for safe discontinuation.

Psychological dependence may persist even after physical withdrawal resolves, particularly in individuals using kratom for mood regulation or chronic pain. Behavioural interventions can support long-term recovery.

Risk of Kratom Overdose or Poisoning

Although kratom overdose is rare, cases have been documented, often involving extremely high doses or contaminated products.⁶

The symptoms of ingesting too much kratom include nausea, vomiting, extreme sedation, respiratory depression, and seizures.

While deaths associated solely with kratom are uncommon, fatalities are more frequent when the plant is combined with other substances such as opioids or alcohol.

High-potency extracts have been linked to a disproportionately higher risk of toxicity. Emergency case reports emphasise that co-use with CNS depressants significantly increases the danger of overdosing on kratom.

Kratom Drug Interactions

Kratom interacts with several medications and substances, which can increase the risk of side effects:

• CNS depressants: Sedatives, alcohol, and opioids may intensify drowsiness or respiratory depression.
• Antidepressants: Serotonergic agents may interact with kratom alkaloids, potentially causing serotonin syndrome.
• Other supplements or drugs metabolised by CYP3A4: May alter kratom metabolism, leading to unpredictable effects.

Additionally, combining kratom with stimulant medications may put strain on the heart and trigger or increase existing anxiety.

Who Is Most at Risk?

Complications from consuming kratom are more likely to manifest in specific populations, especially those with pre-existing health conditions and those who are more advanced in age. The most at-risk groups include:

• Individuals with liver or kidney disease
• Pregnant or breastfeeding women
• People with mental health disorders or a history of substance use
• Older adults or those taking multiple medications

Patients with cardiovascular conditions (e.g., hypertension, arrhythmia) may experience exaggerated effects from kratom’s stimulant properties, including tachycardia or elevated blood pressure.

Is Kratom Addictive?

Kratom has addiction potential, although it is generally considered lower than that of classical opioids. Dependency risk increases with chronic, high-dose use. Compared to caffeine, kratom’s withdrawal and dependence effects are more pronounced. Scientific consensus emphasises caution, particularly for individuals with prior substance use disorders.

The risk of addiction may be strain- and dose-dependent. White-vein and highly concentrated extracts could present higher addictive potential due to more substantial stimulant effects. If you’re comparing varieties, explore what kratom strains are there.

Should You Be Concerned About Kratom Use?

While many users consume kratom without significant complications, evidence points to clear risks:

• Effects are highly individual and strain-dependent
• Long-term safety remains unestablished
• Potential for liver toxicity, cognitive impairment, and dependence exists
• Drug interactions and co-use of alcohol or medications increase danger

Medical consultation is advised if symptoms appear, particularly in chronic users or those taking other substances. Research gaps remain, with limited controlled clinical trials and variable product quality complicating safety assessment.

Emerging studies suggest that potential reproductive, hormonal, and cardiovascular risks remain under-researched. Users are encouraged to report any side effects, especially those that occur with prolonged use.

Remember, no truly safe dose has been established, so start with low doses, monitor for side effects, and source lab-tested kratom from reputable suppliers. Avoid mixing with alcohol, opioids, or prescription sedatives, stay informed about legal status and emerging research, and seek medical advice for prolonged use or unusual symptoms. For background context, see this overview of what is kratom and its origin.

References

1. Kratom: Unsafe and ineffective. Mayo Clinic. Published 2024. https://www.mayoclinic.org/diseases-conditions/prescription-drug-abuse/in-depth/kratom/art-20402171 ↩︎
2. U.S. Food and Drug Administration. FDA and Kratom. U.S. Food and Drug Administration. Published 2019. https://www.fda.gov/news-events/public-health-focus/fda-and-kratom ↩︎
3. FDA CFSAN. Kratom-related Adverse Event Reports (CAERS 2021). Published 2023. https://www.fda.gov/media/169066/download ↩︎
4. Grundmann O. Patterns of Kratom use and health impact in the US—Results from an online survey. Drug and Alcohol Dependence. 2017;176:63-70. doi: https://doi.org/10.1016/j.drugalcdep.2017.03.007 ↩︎
5. Swogger MT, Smith KE, Garcia-Romeu A, et al. Understanding Kratom Use: A Guide for Healthcare Providers. Frontiers in Pharmacology. 2022;13. doi: https://doi.org/10.3389/fphar.2022.801855 ↩︎
6. Anwar M, Law R, Schier J. Notes from the Field: Kratom (Mitragyna speciosa) Exposures Reported to Poison Centers — United States, 2010–2015. MMWR Morbidity and Mortality Weekly Report. 2016;65(29):748-749. doi: https://doi.org/10.15585/mmwr.mm6529a4 ↩︎