Kratom Benefits Evidence: Studies, Side Effects and Safety

If you searched whether kratom has health benefits, the short answer is that none has been proven in people yet. NCCIH, part of the National Institutes of Health, says that “Very little research in people has evaluated the health effects of kratom”, and that kratom “has not been shown to be safe and effective for this or any other medical use.” Most of the human research that does exist looks at risks, so that is where much of this page spends its time.

Kratom at a glance

Is kratom an opioid?

Not under US drug scheduling. NCCIH says kratom and its compounds are not on the federal schedule of controlled substances, although the DEA lists it as a “drug of concern.” In the body, though, it acts on the same receptors. Two of its compounds, mitragynine and 7-hydroxymitragynine (7-OH), interact with opioid receptors in the brain. FDA says these compounds bind the same mu-opioid receptors, the brain receptors that opioid drugs such as codeine act on.

FDA says 7-OH is a naturally occurring alkaloid (a plant chemical) that makes up less than 2% of total alkaloid content in natural leaves, yet it has substantially greater mu-opioid receptor potency than mitragynine and than classical opioids such as morphine.

How is kratom taken, and what does it look like?

NCCIH says people have chewed the leaves or made them into a tea. FDA says products made from the leaves are sold online and in shops. The NCCIH page does not describe how kratom looks. Pills are not described on the NCCIH or FDA pages, so for any pill, the label is where to check what is inside.

What the human evidence shows, use by use

The uses below are ordered by how much human research sits behind each one, starting with the most. If study types like case reports and systematic reviews are new to you, ingredient evidence vs marketing claims is a plain guide to weighing a claim against the type of study behind it.

Opioid withdrawal and cravings

NCCIH says people have reported using kratom to manage opioid withdrawal symptoms and cravings, and that researchers are studying whether it helps. The closest human research on this is a 2021 systematic review, which collects all published cases on a question and summarizes them by a set method, plus a survey of experts. It is about kratom use disorder, meaning a problem with kratom itself, and the medicines used to manage it.

• Study type: systematic literature review, with case reports and posters added, plus a survey of members of the American Society of Addiction Medicine (ASAM).
• Size: 14 reports of long-term management of kratom use disorder, half of them without a co-occurring opioid use disorder.
• Medicines used: mostly buprenorphine, with a few cases of naltrexone and methadone. The review describes all of them as having favorable outcomes.
• Expert survey: among respondents who managed kratom use disorder without a co-occurring opioid use disorder, 89.5% reported using buprenorphine.
• Conclusion: the authors write that “it seems reasonable that the indication for MOUD should be extended to cases of moderate to severe KUD.” MOUD means medications for opioid use disorder, and KUD means kratom use disorder.

So the 2021 review is about treating a kratom problem with prescription medicines. It is not a finding that kratom itself eases withdrawal. The 2021 systematic review and expert survey is listed on PubMed.

Pain

NCCIH says some people in Western countries use kratom to try to treat pain, and that Southeast Asian use has included pain. FDA lists pain among the conditions people self-treat with kratom. These describe use, not results from a study of kratom for pain.

Anxiety, depression and mood

FDA lists anxiety and depression among the conditions people self-treat with kratom. The 2021 review opens by describing an increasing number of Americans turning to kratom for self-management of pain, anxiety and mood states. These are reports of use, not study findings.

Traditional uses: energy, diarrhea and cough

NCCIH says people in Southeast Asia have chewed the leaves or made tea to fight fatigue and improve work productivity, and that kratom has traditionally been used for pain and diarrhea. FDA lists coughing and diarrhea among the conditions people self-treat with it. Tradition describes use over time, and it is not a study result.

What does kratom do to the brain and gut?

On the brain, NCCIH says kratom’s two main compounds interact with opioid receptors in the brain. FDA says mitragynine also acts on other brain chemical messengers, including serotonin, dopamine and norepinephrine, and on kappa opioid receptors.

On the gut, the only benefit people have described is the traditional use for diarrhea. The side effects NCCIH lists include nausea and constipation. FDA says the classic opioid-related effects of these compounds can include sedation, nausea and vomiting, and constipation.

What do kratom effects feel like?

NCCIH says people report two kinds of effects. One is stimulant-like: more energy, alertness and a rapid heart rate. The other is like opioids and sedatives: relaxation, pain relief and confusion. FDA adds that, as with all drugs, the harm kratom can cause depends on how much is taken and under what conditions.

Doses used in studies

The studies do not record doses consistently, so there is no reliable study dose to copy. The table shows what each source says about amount.

Kratom side effects, safety and drug interactions

FDA has warned consumers not to use kratom because of the risk of serious adverse events, including liver toxicity, seizures and substance use disorder. NCCIH lists side effects in two groups, and the table below combines it with the other sources.

Liver injury

A case report is a written account of one patient. The 2026 systematic review on kratom and liver injury, published in the Journal of Addiction Medicine, included 31 studies with 32 cases of kratom-associated liver injury. Most reports came from the United States and were single-patient case reports, and most patients were adult males who often also used other substances. The review describes the injury pattern as mostly cholestatic, meaning bile flow from the liver slows. In most cases, liver enzymes and function improved after kratom use stopped. Formal causality assessments, which test how strongly a drug is linked to an injury, were inconsistently reported. Still, many reports supported an association after other causes were excluded. One author reports in-kind support from Braeburn to receive medications for an NIH-funded clinical trial. The review’s other authors report no conflicts.

Taking it every day

NCCIH says the long-term effects of kratom are not well understood. It also says reports link long-term use of large doses to serious liver problems in some people. Regular users may have withdrawal symptoms when they stop. NCCIH says regular users may have withdrawal symptoms if they stop, and that long-term use of large doses may cause serious liver problems in some people.

Addiction and dependence

NCCIH says kratom itself may have the potential to be addictive, even though people may use it to try to overcome opioid addiction. FDA describes cases of substance use disorder in people who used kratom for longer or in larger amounts than they meant to, had cravings, kept using despite harm, needed more to get the same effect, or had withdrawal when they stopped.

Deaths and mixing with other drugs

NCCIH says fatal overdoses from kratom alone appear to be extremely rare. It also says kratom used with other drugs has been linked to deaths and to severe effects such as liver problems. FDA says that in the deaths it has seen, kratom was usually used with other drugs, and its contribution is unclear.

To report a reaction, FDA asks people to use its MedWatch program or the Safety Reporting Portal.

Who should talk to a clinician first

• Anyone taking prescription medicine or other drugs. NCCIH links kratom used with other drugs to deaths and severe effects. Talk to your prescriber before changing any prescribed medicine.
• Anyone who is pregnant or may become pregnant. FDA reports neonatal abstinence syndrome after prolonged exposure before birth.
• Anyone who notices yellowing of the skin or eyes. The liver review says jaundice was a common presenting sign of kratom-linked liver injury, which is a reason to contact a clinician.
• Anyone with high blood pressure, a history of seizures or heart concerns. NCCIH lists high blood pressure and seizures among serious effects, and the 2026 review lists cardiotoxicity among the concerns raised.
• Anyone who uses kratom daily, has opioid use disorder, or wants to stop. The 2021 review describes prescription medicines for opioid use disorder, and regular users may have withdrawal when they stop. A clinician can assess that risk with you.

What is still unknown

Most of the limits here apply to the whole picture, so they are stated once.

• Whether kratom helps any condition. NCCIH says research on kratom is in its early stages, and that kratom has not been shown to be safe and effective for any medical use.
• The human studies are small and mostly case-based. The 2021 review is 14 reports and an expert survey, not a controlled trial. The 2026 liver review covers 32 cases from 31 studies, most of them single-patient case reports, many with incomplete exposure details.
• Long-term effects and abuse potential. FDA says a well-designed human abuse potential study has not been conducted. FDA funded a single ascending dose study in humans, with results to be published on acceptance, and awarded a grant in September 2024 for a human abuse potential study.
• What a product contains. FDA says kratom contains over 50 alkaloids, and most research focuses on mitragynine and 7-OH. The label and the maker are the places to ask what a given product contains.
• Legal status. NCCIH and FDA describe it differently, as noted in the table above. FDA says state health and law enforcement agencies are the best source for state laws.
• Looks, eyes, skin and hangover.

How to read a label that lists kratom

• Find the form. Leaf powder, tea, an extract and a 7-OH product are different things. FDA says 7-OH is a minor part of natural leaves but much more potent at opioid receptors, so a 7-OH product is not the same as a leaf product.
• Look for an amount. Check whether the label gives an amount of kratom per serving. If it lists a “proprietary blend,” a mix whose exact amounts are kept private, ask the maker how much kratom is in it.
• Check any supplement claim. FDA says kratom is not appropriate for use as a dietary supplement and is not lawfully marketed as one, so a supplement label on a kratom product is a point to ask about.
• Ask for a batch number and test results. NCCIH and FDA both report contamination in some products, including heavy metals and bacteria. A batch or lot number lets you match a product to its test results.
• Read health claims with care. FDA says it acts against companies making false or misleading claims about unproven benefits of kratom.

For a plain guide to weighing product claims against research, see ingredient evidence vs marketing claims. If a product mixes kratom with another plant ingredient, our cbd benefits evidence page covers that ingredient separately.

By ClinicalStudyConnect.com Research Desk

This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.