Kratom

Kratom (Mitragyna speciosa) is a tree native to Southeast Asia, in the coffee family, whose leaves have been used traditionally in the region to relieve fatigue, pain, and opioid withdrawal. The leaves contain dozens of bioactive alkaloids; the two most studied are mitragynine and 7-hydroxymitragynine. People in the United States typically use dried, powdered leaf in capsules, brewed as tea, or as concentrated extracts. At lower doses kratom tends to produce mild stimulant-like effects, while at higher doses its effects are more opioid-like — sedation, pain relief, and euphoria. The U.S. Food and Drug Administration has not approved kratom for any medical use and considers it an unapproved drug and an unsafe food additive; it is not the same as an FDA-reviewed medication, and product contents and potency vary widely between brands.

Kratom's effects come mainly from its alkaloids acting on the brain's opioid system. Mitragynine, the most abundant alkaloid in the leaf, is converted in the body into 7-hydroxymitragynine, and both activate mu-opioid receptors — the same receptors targeted by drugs like morphine and oxycodone — though research suggests their effects only partly resemble those of conventional opioids. Mitragynine also appears to interact with adrenergic, serotonin, and dopamine receptors, which may explain the stimulant-like, arousing effects some people report at lower doses. Because the active compounds engage opioid receptors, kratom can produce tolerance, physical dependence, and withdrawal, and its effects and risks can shift depending on dose and on how concentrated a given product is.

Reported effects depend heavily on dose. At lower doses people often describe increased energy, alertness, talkativeness, and sociability. At higher doses the effects shift toward those associated with opioids: pain relief, calm, sedation, and euphoria. Commonly reported unwanted effects include nausea, vomiting, constipation, itching, sweating, dizziness, dry mouth, and increased urination. Heavy or long-term use is associated with weight loss, fatigue, and — in some reports — liver problems. Regular use can lead to dependence, and stopping after sustained use can produce withdrawal symptoms similar to mild opioid withdrawal, such as irritability, muscle aches, runny nose, and craving.

Although kratom is often marketed as a natural and therefore safe product, it carries real risks. Regular use can cause dependence and an opioid-like withdrawal syndrome. Kratom has been involved in poison-control calls and in deaths, though many reported deaths involved other substances taken at the same time — combining kratom with opioids, benzodiazepines, alcohol, or other depressants is particularly dangerous and can increase the risk of sedation and slowed breathing. Reported harms include liver injury, seizures, rapid heart rate, high blood pressure, and, with very high doses, the opioid risk of respiratory depression. A major current concern is concentrated 7-hydroxymitragynine products (tablets, gummies, shots) that are far more potent than natural leaf and behave much more like strong opioids. Product quality is inconsistent, and kratom products have been found contaminated (for example with Salmonella or heavy metals) or adulterated with other drugs. If someone may have overdosed or taken a dangerous combination, call 911; for poisoning call Poison Control at 1-800-222-1222. For help with dependence, SAMHSA's helpline is 1-800-662-4357.

low dose → alertness, energy, talkativeness, sociability; high dose → opioid-like sedation + euphoria

5–10 min

2–5 hr

nausea, itching, sweating, dry mouth, constipation; addiction + withdrawal; long-term anorexia, weight loss, insomnia, hepatotoxicity; kratom psychosis; overdose + fatalities reported

none in US (used traditionally + self-treatment of opioid withdrawal)

used by SE Asian laborers for centuries; opium substitute

NFLIS >4,000 mitragynine reports since 2010