Pharmacology
DrugBankDescription
Kratom (Mitragyna speciosa) is a medicinal plant species from Southeast Asia. It’s a member of the coffee family (Rubiaceae). Like coffee, kratom is a central nervous system stimulant used to increase energy and productivity. However, the effects of kratom are highly dose-dependent. In lower doses, it’s a stimulant but in higher doses, the effects flip-flop and become sedative instead. As a result, there are a few different reasons someone may want to use kratom. In smaller doses, it’s used much like coffee — as a stimulant and nootropic for use at work or university. In higher doses, kratom is used as an alternative to alcohol (not recommended) for its euphoric effects, to promote sleep, and as an alternative to opiate painkillers. Many of the active ingredients in kratom are powerful opiate agonists — which means they bind to the opioid receptors to block the transmission of pain signals from the body to the brain. This also triggers the release of the feel-good neurotransmitter, dopamine. People addicted to opiates use kratom to wean themselves off the drugs. The effects of kratom help alleviate withdrawal symptoms while undergoing detox for prescription or illicit opiates (more on this later). Kratom is not particularly dangerous, but there are risks to using it. While far less addictive compared to prescription painkillers, kratom is still an opiate. Over time, the body can become dependent on its effects and become addicted.
Receptor Profile
Receptor Actions
History & Culture
Kratom is indigenous to Cambodia, Thailand, Indonesia, Malaysia, Myanmar, and Papua New Guinea, where its leaves have been used in traditional herbal medicine since at least the nineteenth century. The plant has historically been consumed through chewing, smoking, and preparation as a tea. In Thailand, kratom served important social and ceremonial functions, being used as a snack to receive guests and as part of ritual worship of ancestors and gods. The substance was also valued for its practical applications; by 1836, it was reported to be used as an opium substitute in Malaysia, and similar use was documented in Thailand throughout the nineteenth century. Historically, its effects at low doses have been compared to those of coca, while higher doses have been likened to opium.
1839–1859
Mitragyna speciosa was first formally described by the Dutch colonial botanist Pieter Korthals in 1839, who initially named it Stephegyne speciosa. The plant underwent several reclassifications before George Darby Haviland established its current taxonomic name and classification in 1859.
2010–present
Beginning in the 2010s, a tea-based preparation known as "4×100" emerged as a popular recreational drink among young people across Southeast Asia, particularly in Thailand. This cocktail combines kratom leaves with cough syrup, Coca-Cola, and ice. By around 2011, individuals who consumed this preparation were generally viewed more negatively than traditional kratom users, though not as stigmatized as users of substances like heroin. In Western contexts, kratom has gained attention as a self-treatment option for opioid withdrawal, with many individuals using it to ease the transition away from opioid dependence. It has also been occasionally cited as an aid for addressing acute alcohol dependency.
Subjective Effects
Physical
The physical effects of kratom can be broken down into several components which progressively intensify proportional to dosage.
- Stimulation and/or Sedation: An aspect of kratom that one may experience is the change from stimulating to sedating qualities as the dosage increases. Depending on the strain, the sedating and stimulating effects may occur simultaneously in a contradictory manner resulting in the sensation that one is both energized and relaxed. The sedation and stimulation effects may also occur at different times during the experience; a person may feel stimulated during the come up and sedated during the come down. Kratom is considerably more stimulating than that of all other opiates including Oxycodone, heroin, or codeine.
- Euphoria: In comparison to other opioids, this particular substance can be considered as less intense in its physical euphoria when compared with that of morphine or heroin. The sensation itself can be described as extreme feelings of hyper intense physical comfort, snugglyness, warmth, love and blissful euphoria.
- Nausea: If the dose is even slightly too high, one may feel quite ill and the nausea can last upwards of two days at the worst. For this reason, a light and healthy diet is recommended in the days prior to consuming higher doses of kratom.
- Pain relief
- Itchiness
- Constipation
- Difficulty urinating
- Pupil constriction
- Salivation
- Cough suppression
Cognitive
The cognitive effects of kratom can be broken down into several components which progressively intensify proportional to dosage.
- Euphoria: In comparison to other opioids, this particular substance can be considered as less intense in its cognitive euphoria when compared with that of morphine or heroin. The sensation itself can be described as powerful and overwhelming feeling of emotional bliss, contentment, love and happiness.
- Motivation enhancement
- Thought acceleration
- Anxiety suppression
Sensory
The visual effects of kratom are unusually strong compared to other opioids of its class. They can be broken down into several components which progressively intensify proportional to dosage.
- Visual acuity suppression
- Double vision
- Visual disconnection: A sense of subtle disconnection from visual input is often experienced with high dosage kratom. This is similar to a low level version of the same effect universally experienced with dissociatives and may well be a result of the NMDA antagonist effects of kratom's active molecules.
- Internal hallucinations: The internal hallucinations of kratom can be described as more solid than psychedelics and do not seem to be composed of visual geometry. The most common way in which they manifest themselves are through hypnagogic scenarios. They are most common during high dosages and can be comprehensively described through their variations as lucid in believability, fixed in style, autonomous in controllability, and equal in new experiences and memory replays in content.
Forked from Subjective Effect Documentation by Josie Kins, September 2015. Via dose.wiki (CC0).
Toxicity
PsychonautWikiKratom has a low toxicity relative to dose. Like most opioids, safe usage of kratom is not known to cause any dangerous long-term complications. Heavy dosages of kratom can result in increased respiratory depression, leading onto fatal or dangerous levels of anoxia (oxygen deprivation). This is significantly less powerful than the respiratory depression of heroin or morphine. This occurs because the breathing reflex is suppressed by agonism of µ-opioid receptors proportional to the dosage consumed.
Addiction & dependence
As with other opioids, the kratom produces dependence with chronic use and has a high abuse potential. When dependence has developed, cravings and withdrawal symptoms may occur if a person suddenly stops their usage. Tolerance to many of the effects of kratom develops with prolonged and repeated use.
Effect Profile
Curated + 449 ReportsStrong euphoria and focus with moderate stimulation
Strong euphoria, pain relief, and sedation with strong itching/nausea
Empirical Duration
Erowid ReportsMedian times after the dose that Erowid reports state. A curve is drawn only when reports state all four points (onset, peak begins, comedown begins, back to baseline) and the medians fall in that order. No point is estimated from another.
No curve: the stated times run backwards. Reports put the return to baseline (T+2.2h, 14 reports) before the start of the comedown (T+3h, 22 reports). Each time is the median of a different set of reports, so they are shown as stated, not rearranged.
Community Effects
TripSitTolerance & Pharmacokinetics
drugs.wikiNo tolerance chart. Our decay curves for opioids were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.
Opioid tolerance drops fast when you stop, and even a few days off can be enough, so a dose that used to be normal can now stop your breathing. Overdose deaths rise sharply after prison, detox or leaving treatment, and tolerance also falls during a hospital stay. After any break, start with a much smaller amount, try a test dose first, don't use alone, and keep naloxone within reach. Alcohol, benzodiazepines, gabapentinoids and other sedatives make an opioid overdose much more likely.
Sources: FRANK: heroin · National Harm Reduction Coalition · WHO: opioid overdose · Merrall et al. 2010 · Binswanger et al. 2007 · Strang et al. 2003 · FDA 2019: gabapentinoids and breathing
Cross-Tolerances
Demographics
Gender Distribution
Age Distribution
Reports Over Time
Effect Analysis
Erowid + BluelightEffects aggregated from 413 experience reports (363 single-substance Erowid + 86 Bluelight)
Effect Sentiment Distribution
Confidence Distribution
Each bar is the share of reports mentioning the effect; its whisker, and the band on the rows below, is the 95% interval: where the share could plausibly be with other reports of the same kind.
Positive Effects 50
Adverse Effects 41
Show 19 more adverse effects
Show 18 neutral or unclassified mentions
Also reported in combinations. In the 196 Kratom reports where another drug was taken too, 18 (9.2%) mention hospital, emergency services or an overdose, 2 (1.0%) a seizure and 1 (0.5%) psychosis. In the 363 single-substance reports: 5.0%, 0.6% and 1.1%. These are not in the figures above: they cannot be put down to Kratom alone, and a mention is not always something that happened to the writer.
Subjective Effect Ontology
Experience ReportsStructured effect tags extracted from 609 Erowid & Bluelight experience reports using a controlled vocabulary of 220+ canonical effects across 15 domains.
Auditory
Cognitive
Emotional
Gastrointestinal
Motor
Tactile
Dosage Distribution
Dose distribution from experience reports, one dose per report (the first listed). Doses above Q3 + 3×IQR, far above what people typically take, are left out of the median and range and listed under each route: most are real heavy doses or overdoses, not mistakes.
4 reports gave a dose above the typical range (25,000–50,000 mg), so they are not in the figures above. Listing a dose here does not mean it is safe.
Real-World Dose Distribution
ErowidFrom 538 of 738 recorded dose entries: those that state a weight (mg, g or µg), in routes with at least five of them. Values above Q3 + 3×IQR, far above what people typically take, are left out; they can include real heavy doses and overdoses, not only mistakes.
Oral (n=527)
Smoked (n=5)
Common Combinations
Most co-occurring substances, as a share of all 559 reports filed under Kratom; whiskers are 95% intervals
Form / Preparation
Most common forms and preparations, as a share of the 410 reports that give one; whiskers are 95% intervals
Body-Weight Dosing
Dose per kg of body weight, one dose per report (the first listed), from reports giving a weight of 30–250 kg. Doses above Q3 + 3×IQR, far above what people typically take, are left out of the median and range and listed under each route.
3 reports gave a dose above the typical range (422.794–580.046 mg/kg), so they are not in the figures above. Listing a dose here does not mean it is safe.
Show the reports
- 580.046 mg/kg · another drug taken too
- 490.196 mg/kg · another drug taken too
- 422.794 mg/kg
Redose Patterns
Redosing behavior across 477 reports
Legal Status
| Country | Status | Notes |
|---|---|---|
| United Kingdom | Controlled (Psychoactive Substances Act 2016) | Supply and import were prohibited prior to 2016. The Psychoactive Substances Act 2016 subsequently captured kratom under its blanket ban on psychoactive substances, making production, supply, and import illegal. Notably, this legislation was enacted despite kratom being used by some individuals as an aid for opioid withdrawal and alcohol dependency. |
References
Cited References
- Chemical composition and biological effects of kratom (Scientific Reports)
- Drug Users Bible: Kratom
- Erowid: Kratom Basics
- Erowid: Kratom Dose
- Erowid: Kratom Health
- Erowid: Kratom Vault
- EUDA: Kratom Drug Profile
- Kratom—Pharmacology, Clinical Implications, and Outlook (PMC)
- PubChem: Mitragynine
- PsychonautWiki: Kratom
- The Chemical and Pharmacological Properties of Mitragynine (PMC)
- TripSit Factsheet: Kratom
- TripSit Factsheet: Kratom