Purported Benefits, Side Effects & More


Purported Benefits, Side Effects & More

Common Names

  • Kratom; Cratom
  • Ketum; Kakuam
  • Biak
  • Mitragyne; Mitragyna; Mitragynine
  • Thang; Thom

For Patients & Caregivers

Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.

What is it?

Kratom is an herbal supplement that has properties similar to other opioids. It is not recommended as a treatment for pain at this time due to lack of research, harmful side effects, and product contamination.

Kratom is an herbal supplement known to have both stimulant and calming effects. It may also have pain-relieving properties similar to opioids. However, kratom cannot be used as a substitution for prescription pain medications, because studies on its safety or usefulness in humans have not been conducted. Its use is banned in some countries and US states due to potential for abuse. Moreover, some kratom products were recalled due to contamination.

What are the potential uses and benefits?

In general there are very limited data on effects in humans for all uses. More research is needed to determine the safety and effectiveness of this herbal supplement.


Although animal studies suggest kratom may relieve anxiety, it may also cause anxiety in humans during withdrawal.


Kratom appears to have sedative effects at higher doses.

Pain relief

Kratom appears to have pain-relieving effects at higher doses.


Lower doses of kratom have been traditionally used for its stimulating effects. It may also cause appetite suppression.

What are the side effects?

Withdrawal symptoms: Flu-like symptoms such as nausea, vomiting, chills, sweats, muscle spasms and pain, decreased appetite, or diarrhea; anxiety, irritability, depressed mood, hot flashes, sleeping difficulty. Symptoms are more likely with heavier use.

Case reports

Numerous adverse effects involving the use of kratom and mitragynine have been reported in the medical literature across the following categories:

  • Addiction, withdrawal symptoms
  • Depression/anxiety relapse
  • Heart and lung problems
  • Kidney and liver injury
  • Multiorgan dysfunction/failure
  • Psychosis, seizures
  • Tissue damage
  • Temporary paralysis
  • Overdose, death
What else do I need to know?

Patient Warnings:

  • The FDA recently recalled powdered kratom supplements for salmonella contamination and issued a public health advisory against kratom. It also issued warnings of addiction and overdose risks similar to that of other opioids.
  • The Drug Enforcement Administration includes kratom on its Drugs of Concern list. These substances are not currently regulated by the Controlled Substances Act, but pose risks to persons who abuse them. In addition, the National Institute of Drug Abuse identified kratom as an emerging drug of abuse.

Do Not Take if:

  • You have heart problems: Lab studies and case reports suggest kratom could worsen heart problems.
  • You are taking CYP450 or UGT substrate drugs: Kratom may affect the clearance of these drugs.
  • You are taking P-glycoprotein substrate drugs: When taken with psychoactive drugs that are P-gp substrates, mitragynine may cause significant toxicity.

Special Point:

  • Several countries and US states have banned kratom.

For Healthcare Professionals

Scientific Name
Mitragyna speciosa
Clinical Summary

Mitragyna speciosa, commonly known as kratom, is indigenous to Southeast Asia. The leaves have been used in traditional medicine to treat pain, fatigue, fever, diarrhea, and wounds (1), while its extracts are known for their psychoactive properties, especially morphine-like effects (2). Kratom has gained popularity as a supplement to improve mood, and decrease anxiety and pain. It has also been a source of significant controversy. The FDA has issued numerous statements against kratom, citing adverse events, potentially related deaths, risk of addiction or overdose, and incidences of contaminated supplements (3) (4) (5).

Kratom has both stimulant and sedative properties (6). The main psychoactive constituents are mitragynine and 7-hydroxymitragynine (7). In vivo studies of derivative compounds and analogs from kratom demonstrate antinociceptive effects (8). Animal models suggest that kratom has muscle relaxant (9), anti-inflammatory (10), analgesic (11), and anorectic (12) properties. Mitragynine has also shown antioxidant and antiproliferative effects in a few cancer cell lines (13).

Data on the use and safety of kratom in humans are very limited. Stimulant effects occur at lower doses, while sedative and pain-relieving effects occur at higher doses (14). Kratom users may develop physiological dependence and experience withdrawal (15), but this risk has not yet been adequately quantified (16). More research on the therapeutic uses for kratom and its constituents, as well as its toxic effects and abuse potential is needed.

The biological activities of kratom in humans are still poorly characterized (17). Because of its potential interactions with other drugs (18) (19) and possible side effects (20), kratom should not be used as a substitute for prescription pain medications. Several countries and US states have banned the use of kratom due to its potential for abuse (21) (22).

Purported Uses and Benefits
  • Anxiety
  • Insomnia
  • Pain relief
  • Stimulant
Mechanism of Action

The main active alkaloids in kratom are mitragynine and 7-hydroxymitragynine, which is thought to have analgesic effects comparable to morphine (11) (23). Through monoaminergic and opioid receptors, both compounds produce a range of CNS stimulant and depressant effects (23) (24) (25).

Although structurally different (26), mitragynine administration causes cognitive impairment and addiction profiles that closely resemble those of morphine (27). Other research also suggests these compounds share classic opioid characteristics — affinity for opioid receptors, analgesic cross-tolerance, and competitive interaction with naloxone — while possessing other novel attributes (28).

In animal models, anxiolytic-like effects are attributed to opioidergic, GABAergic, and dopaminergic interactions in brain regions (29). Mitragynine may also obstruct neuronal calcium channels (30).

  • The FDA recently recalled powdered kratom supplements for salmonella contamination (5) and issued a public health advisory against kratom (3), with warnings of addiction and overdose risks similar to that of other opioids (4).
  • The Drug Enforcement Administration includes kratom on its Drugs of Concern list. These substances are not currently regulated by the Controlled Substances Act, but pose risks to persons who abuse them. In addition, the National Institute of Drug Abuse identified kratom as an emerging drug of abuse (31).
  • Herbal mixtures that contain synthetic compounds and kratom have been linked to altered behavior (32), hemorrhagic stroke (45) and multiple deaths (33).
  • Patients with tachycardia should avoid using kratom as laboratory studies suggest the potential for cardiotoxicity or exacerbation of Torsade de Pointes (34).
Adverse Reactions

Withdrawal symptoms: Flu-like symptoms such as nausea, vomiting, chills, sweats, muscle spasms and pain, decreased appetite, or diarrhea; anxiety, irritability, depressed mood, hot flashes, sleeping difficulty; symptoms are more likely with heavier use (15) (16) (35).

Case reports

Numerous adverse effects involving the use of kratom and mitragynine have been reported in the medical literature across the following categories (53):

  • Addiction, withdrawal symptoms (14) (36)
  • Depression/anxiety relapse
  • Cardiac or cardiorespiratory arrest (38) (49)
  • Cardiotoxicity (34)
  • Intracerebral hemorrhage
  • Kidney and/or liver injury (37) (50) (51)
  • Multiorgan dysfunction/failure
  • Psychosis
  • Rhabdomyolysis
  • Seizures
  • Transient paralysis
  • Overdose (34) and deaths (3) (34) (39) (40) (33) (41) (31) (46) (47) (48), some with multi-drug circumstances that confound conclusive interpretation (42)
Herb-Drug Interactions
  • CYP450 substrates: Increased clearance of drugs metabolized by CYP450 enzymes (18) (19). Kratom may also inhibit 2D6 (43) and induce 1A2 (44).
  • UGT substrates: Increased clearance of drugs metabolized by UGT1A6 with kratom use (18).
  • P-glycoprotein substrates: Mitragynine inhibits P-gp in vitro, and concurrent administration with psychoactive drugs that are P-gp substrates may cause significant toxicity (52).
  1. Hassan Z, Muzaimi M, Navaratnam V, et al. From Kratom to mitragynine and its derivatives: physiological and behavioural effects related to use, abuse, and addiction. Neurosci Biobehav Rev. Feb 2013;37(2):138-151.
  2. Sabetghadam A, Ramanathan S, Sasidharan S, et al. Subchronic exposure to mitragynine, the principal alkaloid of Mitragyna speciosa, in rats. J Ethnopharmacol. Apr 19 2013;146(3):815-823.
  3. U.S. Food and Drug Administration. Statement from FDA Commissioner Scott Gottlieb, M.D., on the agency’s scientific evidence on the presence of opioid compounds in kratom, underscoring its potential for abuse. February 6, 2018.
  4. U.S. Food and Drug Administration. FDA oversees destruction and recall of kratom products; and reiterates its concerns on risks associated with this opioid. February 21, 2018.
  5. U.S. Food and Drug Administration. FDA orders mandatory recall for kratom products due to risk of salmonella. April 3, 2018.
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  8. Varadi A, Marrone GF, Palmer TC, et al. Mitragynine/Corynantheidine Pseudoindoxyls As Opioid Analgesics with Mu Agonism and Delta Antagonism, Which Do Not Recruit beta-Arrestin-2. J Med Chem. Sep 22 2016;59(18):8381-8397.
  9. Chittrakarn S, Keawpradub N, Sawangjaroen K, et al. The neuromuscular blockade produced by pure alkaloid, mitragynine and methanol extract of kratom leaves (Mitragyna speciosa Korth.). J Ethnopharmacol. Jun 16 2010;129(3):344-349.
  10. Shaik Mossadeq WM, Sulaiman MR, Tengku Mohamad TA, et al. Anti-inflammatory and antinociceptive effects of Mitragyna speciosa Korth methanolic extract. Med Princ Pract. 2009;18(5):378-384.
  11. Takayama H. Chemistry and pharmacology of analgesic indole alkaloids from the rubiaceous plant, Mitragyna speciosa. Chem Pharm Bull (Tokyo). Aug 2004;52(8):916-928.
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  13. Goh TB, Koh RY, Mordi MN, et al. Antioxidant value and antiproliferative efficacy of mitragynine and a silane reduced analogue. Asian Pac J Cancer Prev. 2014;15(14):5659-5665.
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  20. Lydecker AG, Sharma A, McCurdy CR, et al. Suspected Adulteration of Commercial Kratom Products with 7-Hydroxymitragynine. J Med Toxicol. Dec 2016;12(4):341-349.
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  26. Prozialeck WC, Jivan JK, Andurkar SV. Pharmacology of kratom: an emerging botanical agent with stimulant, analgesic and opioid-like effects. J Am Osteopath Assoc. Dec 2012;112(12):792-799.
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  28. Raffa RB, Beckett JR, Brahmbhatt VN, et al. Orally active opioid compounds from a non-poppy source. J Med Chem. Jun 27 2013;56(12):4840-4848.
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  46. Hughes RL. Fatal combination of mitragynine and quetiapine - a case report with discussion of a potential herb-drug interaction. Forensic Sci Med Pathol. 2019 Mar;15(1):110-113.
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