Kratom.
Kratom leaf carries alkaloids that act at opioid receptors. People use it for stimulation lower down and sedation higher up, and it has a recognised tolerance and withdrawal profile.
- Category
- Herb
What Kratom is, and what it does.
- Does it work
- This suits adults who have read the pharmacology and checked their local law, which differs by country and state. Anyone on medication should speak to a clinician first.
- How much to take
- No dose figure is on record, and leaf alkaloid content varies several fold between products, so an amount from one bag does not carry over to another.
- Time to feel it
- This one is felt within the same session rather than over weeks, and part of the activity appears only after the liver converts mitragynine to a stronger metabolite.
- The first dose
- Day one is noticeable. Reported effects run from alertness to sedation depending on amount and product, with nausea and itching common early on.
- With regular use
- Regular use builds tolerance, so the same amount does less, and stopping after sustained use brings a recognised withdrawal syndrome. That is the central long-term fact.
- How well tolerated
- Take this one seriously. Tolerance, dependence and withdrawal are documented, extracts run far stronger than leaf, and CYP3A4 interactions shift exposure. Talk to a clinician.
- How it feels
- People describe a coffee-like lift at lower intake and a heavy, sedating calm higher up. Nausea, sweating and itching are common, and products vary a lot.
- The overlooked benefit
- Concentrated 7-hydroxymitragynine extracts are a different exposure from whole leaf powder, so the wording on the front of the pack changes the pharmacology in the bag.
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
- Opioid receptor agonism by mitragynine and 7-hydroxymitragynineIn vitro study
- Metabolic conversion of mitragynine to 7-hydroxymitragynineAnimal study
- Self-reported stimulation at lower intake and sedation at higher intakeCohort study
- Tolerance and withdrawal with sustained regular useCohort study
- CYP3A4 mediated interactions with co-taken medicinesNarrative review
Why these belong in the same formula. Each row says what the basis is, from settled biochemistry through to a trial that measured the pair.
Mitragynine has documented activity at opioid and adrenergic receptors, and caffeine is an adenosine antagonist with its own pressor effect. Taken together the effects on heart rate and blood pressure can stack in a way neither predicts alone. A case report describes right ventricular dysfunction associated with kratom, which is a signal to take seriously rather than a demonstrated dose response.
Passionflower is mild on its own, which is exactly why it gets stacked without much thought. Layered onto mitragynine the sedative burden rises. No controlled work has quantified the combination.
Combining a serotonin precursor with an agent that has any serotonergic activity raises theoretical concern about excessive serotonergic tone. The receptor pharmacology of mitragynine is still being characterised and the size of the serotonergic contribution is unclear. Flagging the direction is the honest position.
Induction of CYP3A4 accelerates mitragynine clearance and lowers exposure, and stopping the inducer removes that effect over days to weeks. The result is an unpredictable exposure profile in either direction. This is the kind of interaction people do not anticipate because both products are sold as botanicals.
Inhibition of clearance raises exposure to a compound whose dose response is already steep and poorly mapped. The in vitro inhibition data does not reliably predict what happens at dietary curcumin intakes. Read it as mechanistic rather than clinical.
Mitragynine is a CYP3A4 substrate, so intestinal inhibition increases the fraction reaching circulation. The inhibition lasts until enzyme is resynthesised, which takes days, so timing the two apart does not solve it. This is one of the better characterised food interactions in pharmacology.
Opioid receptor agonism reduces propulsive motility and increases fluid absorption in the colon, which is why the effect is so reliable. Osmotic magnesium works by an unrelated mechanism and does not counter the receptor activity itself. This is symptom management, not correction of the cause.
Products marketing a piperine boosted botanical rarely spell out that the boost is inhibition of clearance. With an alkaloid of narrow and uncertain exposure margins, raising exposure without changing the label dose is a real hazard. Regard the pairing as raising exposure, not improving quality.
Nothing specific on file for Kratom. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.What Kratom actually does.
Kratom is the leaf of a tree in the coffee family from Southeast Asia. Its main active compound is present in fresh leaf, with a much more potent related compound present in far smaller amounts.
That main compound is broken down largely by one liver enzyme, so anything that speeds up or slows down that enzyme meaningfully changes exposure. This explains most of the reported interactions with other substances.
How much active compound is in the leaf varies a lot depending on the plant variety, growing conditions, leaf age and drying method, so two products labeled the same way can differ several times over in strength.
Concentrated extracts and products isolated to contain just the more potent compound carry a very different exposure than traditional whole leaf powder, since that compound reaches levels the leaf itself never does.
Where Kratom comes from.
Kratom is the dried leaf of a Southeast Asian tree related to coffee. What is in the leaf depends heavily on where and how it was grown, so two bags with the same label can be quite different in strength. The bigger issue is that some products are not leaf at all but concentrated extracts, and those act on the same receptors as opioid medicines, at a strength the plant never produces on its own. Legal status varies by country and by state, and it is worth checking before ordering.
Made from a plant. What ends up in the capsule tracks the harvest, so batch testing and a stated marker matter more here than with a made molecule.
Leaf of a tree in the Rubiaceae family, the same family as coffee, grown mainly in Indonesia with smaller production in Thailand and Malaysia. Alkaloid content depends on cultivar, leaf maturity, soil mineral ratios and light exposure.
Leaves are stripped, dried in sun or shade, and the drying route changes the alkaloid profile. Commercial vein colour designations reflect drying and handling as much as any botanical difference.
Dried leaf is milled to powder, or extracted with water or alcohol to concentrate the alkaloid fraction. Extraction conditions alter the ratio between alkaloids rather than simply concentrating them proportionally.
Some products go further, isolating mitragynine or enriching 7 hydroxymitragynine well above natural leaf levels. This step is what separates a leaf product from a concentrated alkaloid preparation.
Where testing is done at all, material is assayed for mitragynine and 7 hydroxymitragynine content. Independent testing has repeatedly found label content diverging from measured content in this category.
Sold as loose leaf powder, capsules, liquid extract shots and enriched concentrates. Legal status varies by country and by state or province, and several jurisdictions restrict the enriched forms specifically.
The forms it comes in.
The essence, in one line each.
- Describes acute right ventricular dysfunction in a patient associated with kratom use, with the diagnostic workup and management course reported in a single individual.Case report. Alameh I et al., 2025 (JACC: Case Reports). PMID 40713117 ↗
- Reviews the pharmacology and biosynthesis of Mitragyna alkaloids and the biotechnological routes being explored to produce them.Narrative review. Wangmo KS et al., 2026 (Journal of Genetic Engineering and Biotechnology). PMID 42309612 ↗
- Uses biocatalytic halogenation and oxidation of mitragynine to probe how structural changes alter opioid receptor activity in cell based assays.In vitro study. Harris NR et al., 2026 (ACS Chemical Biology). PMID 41906286 ↗
- Argues that the current regulatory framework for dietary supplements permits a high volume of adverse event reports, with kratom cited among the products generating them.Narrative review. Li W et al., 2023 (Innovations in Pharmacy). PMID 38035313 ↗
- Dried kratom leaf with yeast in ruminant feed altered digestibility and rumen fermentation parameters, an agricultural feed finding with no bearing on human use.Animal study. Va S et al., 2024 (Animal Bioscience). PMID 38098130 ↗
- UV-B and far-red light exposure altered plant morphology and alkaloid profile in cultivated kratom, showing that growing conditions shift the chemistry of the leaf.In vitro study. Zhang M et al., 2026 (Frontiers in Plant Science). PMID 42292999 ↗
- Soil calcium to magnesium ratio influenced mitragynine yield and seedling growth in cultivated kratom, further evidence that alkaloid content is agronomically variable.In vitro study. Leksungnoen N et al., 2026 (Plants). PMID 41977757 ↗
These are the studies our verdict leans on, chosen from the 7 we read for Kratom. The full linked list is below.
The studies, linked.
12 sources behind our Kratom verdict: peer-reviewed studies and registered clinical trials. Every one links straight to PubMed, the journal, or ClinicalTrials.gov. Read them yourself.
- Clinical trialReal-world Momentary Assessment of Kratom Use Accompanied by Product Assays: A Natural-history Study for Interdisciplinary Characterization of Kratom Use and PharmacologyClinicalTrials.gov ↗396 participants, Completed
- Clinical trialAdaptive Study to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of Single Ascending Doses of Kratom in Healthy, Nondependent, Adult Recreational Polydrug Users With Opioid ExperienceClinicalTrials.gov ↗Phase 1, 40 participants, Completed
- Clinical trialAssessing the Pharmacokinetics and Drug Interaction Liability of Kratom, an Opioid-like Natural ProductClinicalTrials.gov ↗Early phase 1, 15 participants, Completed
- Clinical trialPreliminary Characterization of Commercial Kratom Extract ProductsClinicalTrials.gov ↗2 participants, Terminated
- Clinical trialA Randomized, Double-Blind, Placebo-Controlled Study to Assess the Effects of Feel Free® Classic Tonic on Self-Perceived Stress and Pharmacokinetic Profile in Healthy AdultsClinicalTrials.gov ↗165 participants, Recruiting
- Clinical trialEvaluation of the Safety and Effects of Psychoactive Substances in People With Past Opioid UseClinicalTrials.gov ↗Phase 1, 72 participants, Not yet recruiting
- Clinical trialEffectiveness of Mitragynine Topical Patch From Kratom for Pain Reduction in Myofascial Pain Syndrome of Upper Trapezius Muscle: Double Blinded Placebo, Randomized Controlled TrialClinicalTrials.gov ↗Phase 3, 64 participants, Not yet recruiting
- Clinical trialKratom Use Disorder Management Using Clonidine and/or BuprenorphineClinicalTrials.gov ↗50 participants, Recruiting
- Clinical trialObserving the Acute Effects Following a Single Oral Dose of Kratom and Effects Following Kratom Cessation Among Adults Who Use Regularly.ClinicalTrials.gov ↗22 participants, Recruiting
- ClinicalTrials.gov ↗
- Clinical trialA Randomized, Double-Blind, 3-Period Crossover, Pharmacokinetic Study in Healthy Adults to Compare Combined Kava and Kratom Supplementation With Kava or Kratom Alone Under Fasted ConditionsClinicalTrials.gov ↗18 participants, Active not recruiting
- Clinical trialEvaluating a Potential Pharmacokinetic Kratom-oxycodone Interaction Concurrent With Clinical EndpointsClinicalTrials.gov ↗Early phase 1, 16 participants, Recruiting
Evidence surfaced via Semantic Scholar (Allen Institute for AI) and ClinicalTrials.gov. Ranked by study type and citation weight, not cherry-picked.
Problems people have reported.
Read this carefully. These are 1,219 voluntary, unverified reactions reported to the FDA (openFDA). The number mostly reflects how popular Kratom is, not how risky it is. A report is not proof Kratom caused anything. It is a signal of what to watch for, nothing more.
Source: openFDA adverse-event reports. Voluntary reporting, not an incidence rate.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.