Kratom (Mitragyna speciosa) is a tropical tree from Southeast Asia whose leaves contain mitragynine and 7-hydroxymitragynine, alkaloids that act on mu-opioid receptors in the brain. At low doses, kratom produces stimulant-like effects; at higher doses, it produces opioid-like sedation, euphoria, and pain relief. Despite being marketed as a natural supplement, kratom carries genuine risks of dependence, withdrawal, and adverse health effects. The FDA has not approved kratom for any medical use, and the DEA has identified it as a drug of concern. Understanding kratom’s pharmacology rather than its marketing is essential for anyone considering or currently using this substance.
Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician, Phuket Island Rehab
“Kratom occupies a complicated space in our clinical practice,” says Dr. Ponlawat Pitsuwan. “Here in Thailand, where kratom is indigenous and has centuries of traditional use, we see the full spectrum: people using small amounts of fresh leaf as a mild stimulant, people consuming large quantities of concentrated extracts for opioid-like effects, and people who initially turned to kratom to manage opioid withdrawal and have now developed kratom dependence. The pharmacology is clear: kratom acts on opioid receptors, and chronic use produces opioid-type dependence and withdrawal.”
Kratom’s Active Compounds and How They Work
Kratom leaves contain over 40 alkaloids, but two are pharmacologically dominant. Mitragynine, which constitutes approximately 66% of the alkaloid content, is a partial agonist at mu-opioid receptors and also interacts with adrenergic, serotonergic, and dopaminergic systems. 7-hydroxymitragynine, present in much smaller quantities (approximately 2% of alkaloid content), is approximately 13 times more potent than morphine at the mu-opioid receptor and is believed to be the primary driver of kratom’s opioid-like effects at higher doses.
This dual pharmacological profile explains kratom’s dose-dependent effects. At low doses (1 to 5 grams of dried leaf), mitragynine’s interaction with adrenergic receptors predominates, producing stimulation, increased energy, alertness, and sociability similar to caffeine or coca leaf. At higher doses (5 to 15 grams), the mu-opioid receptor activation by both mitragynine and 7-hydroxymitragynine becomes dominant, producing analgesia, sedation, euphoria, and the characteristic opioid warmth that users describe. This is the dose range where dependence risk escalates significantly.
Mitragynine is metabolised primarily by the CYP3A4 and CYP2D6 hepatic enzymes. This creates potential drug interactions with medications that are metabolised by or inhibit these same pathways, including many antidepressants, antipsychotics, and other opioids. The pharmacokinetic interactions of kratom are poorly characterised because of its unregulated status, which means users combining kratom with other substances are navigating unknown interaction territory.
Kratom Effects by Dose Range
| Dose Range (Dried Leaf) | Dominant Effect | Primary Mechanism | Dependence Risk |
|---|---|---|---|
| 1 to 3 grams | Mild stimulation, increased energy, focus | Adrenergic receptor activation | Low with occasional use |
| 3 to 5 grams | Moderate stimulation with mild opioid effects | Mixed adrenergic and mu-opioid | Moderate with daily use |
| 5 to 10 grams | Opioid-like sedation, euphoria, pain relief | Mu-opioid receptor agonism dominant | High with regular use |
| 10 to 15+ grams | Strong sedation, nausea, potential respiratory effects | Heavy mu-opioid receptor activation | Very high; tolerance escalation likely |
| Concentrated extracts | Intensified opioid effects, unpredictable potency | Elevated 7-hydroxymitragynine concentration | Very high; rapid tolerance development |
The Dependence and Withdrawal Problem
Because kratom activates mu-opioid receptors, chronic use produces the same neuroadaptive changes seen with other opioids: receptor downregulation, reduced endogenous opioid production, and tolerance. Users who take kratom daily for several weeks or longer develop physical dependence, meaning they experience withdrawal symptoms upon cessation. The withdrawal syndrome resembles opioid withdrawal: muscle aches, insomnia, irritability, anxiety, nausea, diarrhoea, sweating, runny nose, and craving.
Kratom withdrawal is generally less severe than withdrawal from heroin or prescription opioids but more significant than many users expect based on kratom’s marketing as a “natural herb.” Symptoms typically begin 12 to 24 hours after the last dose, peak at days 2 to 4, and resolve within 7 to 10 days. However, the psychological withdrawal component, including anxiety, dysphoria, and craving, can persist for weeks, driving relapse. Users who have escalated to concentrated extracts or very high daily doses may experience more severe and prolonged withdrawal.
A pattern frequently seen in clinical practice is the escalation cycle. A user begins with low doses of plain leaf for energy or mild pain relief. Tolerance develops, doses increase, and the user transitions to concentrated extracts (marketed as “enhanced” or “gold” kratom) to achieve the same effects. At this stage, the user is consuming amounts of 7-hydroxymitragynine that produce significant opioid-like dependence, and attempts to stop result in withdrawal symptoms that drive continued use.
Clinical insight: At Phuket Island Rehab, we treat kratom dependence with the same clinical framework as other opioid use disorders. Patients presenting with significant kratom dependence may benefit from a short buprenorphine-assisted taper to manage withdrawal comfortably, followed by the same therapeutic programme used for other substance dependencies. The most common treatment barrier is the patient’s reluctance to accept that a “natural supplement” has produced a genuine substance use disorder.
Health Risks Beyond Dependence
Kratom’s unregulated status creates health risks that extend beyond its pharmacological effects. Products sold as kratom have been found to contain contaminants including heavy metals (lead, nickel), Salmonella, and in some cases, other psychoactive substances not listed on the label. A 2018 Salmonella outbreak linked to contaminated kratom products in the United States resulted in 199 infections across 41 states.
Hepatotoxicity (liver injury) has been reported in association with kratom use, though the mechanism is not fully understood. Case reports describe cholestatic liver injury appearing within 1 to 8 weeks of kratom initiation, with elevated bilirubin, alkaline phosphatase, and transaminases. Most cases resolve upon discontinuation, but some have required medical intervention. Whether the hepatotoxicity is caused by mitragynine itself, a contaminant, or an individual susceptibility factor remains under investigation.
Kratom-associated deaths have been documented, though most involve polysubstance use. The CDC analysed kratom-associated deaths from 2016 to 2017 and found that 80% of decedents had other substances in their system, most commonly fentanyl, heroin, benzodiazepines, or alcohol. Cases where kratom was the sole substance detected are rarer but have been reported, particularly with concentrated extracts. The combination of kratom with other CNS depressants appears to carry the highest mortality risk.
Kratom for Opioid Withdrawal: Does It Work?
One of the most common reasons people use kratom is to self-manage opioid withdrawal. Because kratom activates the same mu-opioid receptors, it does reduce opioid withdrawal symptoms. However, this is not a cure for opioid dependence; it is a substitution of one mu-opioid agonist for another. The user may successfully avoid heroin or prescription opioid withdrawal but will develop kratom dependence over time, creating a new substance use disorder.
Evidence-based medication-assisted treatment with buprenorphine or methadone provides the same receptor-level relief of withdrawal and craving but with pharmaceutical-grade purity, known dosing, clinical oversight, proven safety data, and integration with therapeutic support. Kratom offers none of these safeguards. The American Society of Addiction Medicine, NIDA, and other professional bodies do not endorse kratom as a treatment for opioid use disorder.
When Substance Use Has Become More Than Occasional
If your kratom use has progressed from occasional to daily, if you have escalated from plain leaf to concentrated extracts, if you feel unwell when you miss a dose, if you spend significant time and money obtaining kratom, or if you have tried to reduce or stop and been unable to, these patterns indicate substance dependence. The fact that kratom is sold as a supplement does not change the pharmacological reality of mu-opioid receptor dependence.
Kratom dependence responds to the same clinical approaches used for other opioid use disorders. Medical detoxification, which may include buprenorphine-assisted tapering for severe dependence, addresses the physical component. Therapeutic programmes address the psychological drivers, coping deficits, and co-occurring mental health conditions that sustain substance use. Residential treatment at Phuket Island Rehab provides both components in a structured, supportive environment.
Summary
Kratom contains alkaloids that activate mu-opioid receptors, producing dose-dependent effects ranging from stimulation to opioid-like sedation and euphoria. Chronic use produces opioid-type physical dependence and withdrawal. Additional health risks include hepatotoxicity, contamination with heavy metals and pathogens, and polysubstance overdose risk. While kratom may temporarily manage opioid withdrawal symptoms, it does so by substituting one mu-opioid agonist for another, creating new dependence rather than resolving the underlying condition. Evidence-based treatments are superior to kratom for opioid use disorder management.
“Kratom’s natural origin does not make it pharmacologically benign,” says Dr. Ponlawat Pitsuwan. “The opioid receptors in the brain do not distinguish between a synthetic molecule and a plant-derived alkaloid. What matters is the binding affinity and the consequences of chronic receptor activation, and on those measures, kratom behaves like an opioid because it is one. Patients who recognise this and seek appropriate clinical support for kratom dependence achieve far better outcomes than those who continue cycling between kratom products searching for one that will not cause dependence.”
Frequently Asked Questions
Is kratom legal?
Kratom’s legal status varies widely by country and, in the United States, by state. As of 2025, kratom is legal at the federal level in the US but banned in several states including Alabama, Arkansas, Indiana, Rhode Island, Vermont, and Wisconsin. In Thailand, kratom was decriminalised in 2021 after decades of prohibition and is now regulated. It is illegal in Australia, several European countries, and many Southeast Asian nations. Legal status does not indicate safety or medical approval; the FDA has explicitly warned against kratom use and has not approved it for any therapeutic purpose.
Can you overdose on kratom?
Fatal overdose from kratom alone is rare but documented, particularly with concentrated extracts. The greater overdose risk comes from combining kratom with other CNS depressants such as benzodiazepines, alcohol, or other opioids. In these polysubstance scenarios, the additive respiratory depression can be fatal. The CDC’s analysis of kratom-associated deaths found that 80% involved other substances. However, the inconsistent potency of unregulated kratom products means that a user cannot reliably predict the dose they are taking, which increases the risk of unintentional overdose, especially with concentrated extracts.
How long does kratom withdrawal last?
Acute kratom withdrawal typically lasts 5 to 10 days, with symptom onset at 12 to 24 hours and peak intensity at days 2 to 4. Symptoms include muscle aches, insomnia, anxiety, irritability, nausea, diarrhoea, and craving. Post-acute symptoms such as low mood, fatigue, intermittent anxiety, and sleep disturbance can persist for 2 to 4 weeks in moderate users and longer in those who were using high doses or concentrated extracts for extended periods.
Is kratom safer than heroin or prescription opioids?
Kratom is less potent than heroin or prescription opioids like oxycodone, which means the acute overdose risk from kratom alone is lower. However, “less dangerous” is not the same as “safe.” Kratom produces genuine opioid dependence, its unregulated status means product purity and potency are unreliable, and its interaction with other substances can be dangerous. The appropriate comparison is not kratom versus heroin but kratom versus evidence-based treatments like buprenorphine, which provides the same receptor-level benefits with pharmaceutical-grade safety, known dosing, and clinical oversight.
Can kratom damage the liver?
Yes. Kratom-associated hepatotoxicity has been documented in clinical case reports, presenting as cholestatic liver injury with elevated bilirubin, alkaline phosphatase, and liver enzymes. Onset typically occurs within 1 to 8 weeks of regular use. Most cases resolve upon discontinuation of kratom, but some have been severe enough to require medical intervention. The mechanism is not fully understood and may involve direct toxicity from kratom alkaloids, contaminants in unregulated products, or individual genetic susceptibility.
Should I use kratom to get off opioids?
Using kratom for opioid withdrawal substitutes one mu-opioid agonist for another, trading one dependence for another. While kratom may temporarily ease withdrawal symptoms, it does not treat opioid use disorder and creates new risks including unregulated product quality, hepatotoxicity, and kratom dependence. Evidence-based medication-assisted treatment with buprenorphine or methadone provides the same receptor-level benefits with pharmaceutical purity, proven safety data, known dosing, and integration with therapeutic support. If you are considering kratom for opioid withdrawal, consult a clinician about MAT options instead.
Sources
National Institute on Drug Abuse (NIDA). “Kratom DrugFacts.” National Institutes of Health. drugabuse.gov
US Food and Drug Administration. “FDA and Kratom.” fda.gov
Centers for Disease Control and Prevention. “Notes from the Field: Unintentional Drug Overdose Deaths with Kratom Detected.” Morbidity and Mortality Weekly Report. cdc.gov
Kratom · Mitragyna speciosa · Mitragynine · 7-hydroxymitragynine · Mu-opioid receptor · Partial agonist · CYP3A4 · CYP2D6 · Opioid-induced hyperalgesia · Hepatotoxicity · Buprenorphine · Methadone · Opioid use disorder · Salmonella · FDA · DEA · Phuket Island Rehab