Kratom (mitragynine, 7-OH)

What kratom is

Kratom comes from the tree Mitragyna speciosa. Traditionally, fresh or dried leaves are chewed or brewed into tea. The European drug monitoring centre EMCDDA describes uses against exhaustion during long working days, against diarrhoea and cough, as a wound dressing and as a substitute for opium or heroin. Today, besides leaf powder, there are also concentrated extracts; in the USA, tablets, gummies and films with enriched 7-OH have been added.

What is rated is the state of knowledge, and it is thin. There is one small controlled study on pain perception, a few safety studies in healthy people, large surveys of users and analyses of deaths. Other herbal or psychoactive substances with their own entry are Kava, Kanna and Phenibut; on the subject of pain see Chronic pain.

How it works

Dried leaves contain 0.5 to 1.5 percent alkaloids. The main compound is mitragynine, whose share varies greatly depending on origin: in Thai varieties up to two thirds of the alkaloids, in Malaysian ones about one eighth. 7-Hydroxymitragynine, 7-OH for short, makes up less than 2 percent of the alkaloids in the plant. However, it is formed in the body as an active metabolite of mitragynine and can be produced from it in a single chemical step.

Mitragynine and 7-OH activate the μ-opioid receptor, at which morphine also acts; the antidote naloxone reverses the effect. In addition, adrenergic and serotonin receptors are engaged. This results in an unusual dual profile, which the expert commission at the BfArM also describes: stimulating at low amounts, sedating and opioid-like at high ones. In humans, the opioid effect has been measured as constriction of the pupils.

What the studies show

Vicknasingam 2020: the ice-water test

The 26 participants from Malaysia, on average 24 years old, had been drinking kratom daily for an average of 6.1 years. On a study day in the clinic, they received in random order a kratom decoction and a placebo that tasted the same. What was measured was how long they kept their hand in ice water after the onset of pain. After kratom, the time rose on average from 11.2 to 24.9 seconds, after placebo it stayed the same. Because only young men with long-standing use took part, this says little about pain patients or people without kratom experience.

Huestis 2026: the largest controlled study

116 healthy adults who had never taken kratom or had not taken it for at least a year received, double-blind, dried leaf powder at four ascending levels or placebo, first once, then daily for 15 days, and were then followed up for up to four weeks. There were no serious side effects and no deaths. Side effects increased with the amount: after the single dose mainly dizziness, nausea and a feeling of relaxation, with daily intake headache, a feeling of heat, elevated liver values and nausea. A standardized product from one manufacturer was tested.

Reissig 2026: kratom in opioid-experienced people

40 healthy people with experience of recreational drug use including opioids received a single dose of kratom leaf powder at five ascending levels or placebo. In its alkaloids, the powder corresponded to commercially available leaves and contained only traces of 7-OH. From the second level, the pupils constricted, a typical opioid sign. Only the highest level increased ratings such as “drug liking”, “good effect” and “high”. There were no serious side effects; the most common were drowsiness, vomiting and nausea.

What users report: Garcia-Romeu 2020

The anonymous online survey from 2017 reached 2,798 people who used kratom, almost all in the USA, on average 40 years old, 61 percent women. 59 percent took it daily. As reasons they named pain (91 percent), anxiety (67 percent) and depression (65 percent), each with high self-rated effectiveness. 41 percent used kratom to reduce or stop opioids, and 411 people attributed more than a year of opioid abstinence to it. About one third reported side effects, mostly mild and shorter than 24 hours; 2 percent met the criteria for a moderate or severe use disorder. Such a voluntary survey is not representative.

Where the data stop

• No study in patients. Whether kratom helps with chronic pain, anxiety, depression or in opioid withdrawal has not been tested in any controlled study in those affected. The positive statements on this come from surveys.
• Only short periods. The longest controlled administration lasted 15 days, in healthy people. In the large survey, the majority took kratom daily.
• Products are not comparable. The mitragynine content varies many times over depending on origin, and concentrated 7-OH products contain, according to the DEA, considerably more 7-OH than the leaf. The authors of the pilot study stress that their results need not apply to other kratom products.
• Risks hard to quantify. In deaths with kratom detected, other substances were almost always found. How common dependence or liver damage are with sole use over longer periods is open.

Status, approval and legal

In Germany, kratom is not approved as a medicine. On July 1, 2025, the BfArM warned against its use for medical purposes: safety and efficacy had not been sufficiently tested, and a positive benefit-risk ratio had not been demonstrated. Kratom is not a narcotic; after consideration by the expert committee, it was not included in the annexes of the Narcotics Act (BtMG). Whether kratom products are to be classified as medicines or as foods has been under discussion since 2024 by the Joint Expert Commission for the Classification of Substances; according to the minutes of its 41st meeting, published on October 19, 2026, its opinion is still pending. Decisions on individual products are taken by the state authorities, for example when a product is advertised as a remedy for diseases; according to the BfArM, individual federal states have already taken action.

In the EU, kratom is not regulated uniformly, and it is not listed in the United Nations drug control conventions. According to the EMCDDA drug profile, at least 12 countries in its monitoring network control kratom, including Denmark, Estonia, Finland, France, Italy, Latvia, Lithuania, Poland, Portugal, Romania and Sweden. Czechia has added kratom to a list of so-called psychomodulatory substances, which are not banned in principle but whose trade and use are regulated.

In the USA, kratom is not approved as a medicine, but it is not banned either. The focus is on concentrated 7-OH products. The Department of Health and Human Services (HHS) recommended in July 2025 and again on October 8, 2026, that 7-OH be placed under narcotics law. Since August 26, 2026, the semi-synthetic derivative mitragynine pseudoindoxyl has been temporarily in Schedule I, the strictest category. On October 14, 2026, the DEA announced that it would also temporarily place 7-OH and mitragynine pseudoindoxyl above a threshold in Schedule I; the order may be issued no earlier than 30 days after the announcement. The kratom leaf and mitragynine itself are not covered by this.

Safety

Kratom acts in an opioid-like way, and the most important risks follow from this. The BfArM refers to animal and human data on dependence and withdrawal syndrome as well as on possible damage to the liver and kidneys; for reported deaths, the causes are still being investigated. In the largest controlled study, elevated liver values with 15-day intake were among the most common side effects. In opioid-experienced people, the highest amount tested increased typical signs of abuse potential such as “drug liking” and “high”.

The US health agency CDC analysed 27,338 overdose deaths from 27 states between July 2016 and December 2017. In 152, kratom was detectable, and in 91 it was considered one of the causes of death. Only in 7 of the deceased was kratom alone found, although other substances could not be ruled out with certainty there either. In 65 percent, fentanyl was found at the same time, in 33 percent heroin, in 22 percent benzodiazepines and in 20 percent prescription opioids. What is dangerous is therefore above all the combination with other sedating substances.

Particularly risky: 7-OH concentrates

Products with enriched or semi-synthetic 7-OH are not the same as the leaf. According to the DEA, 7-OH has a pharmacological profile similar to morphine; preclinical data show tolerance, dependence and respiratory depression as with classic opioids. There are no controlled studies in humans on these concentrates. Some are marketed as dietary supplements or natural extracts, although according to the DEA they do not meet the definitions for these.

Sources

• Vicknasingam B et al., Yale J Biol Med 2020 – kratom and pain tolerance, randomized, placebo-controlled, double-blind
• Huestis MA et al., Ther Drug Monit 2026 – safety and tolerability of kratom leaf powder, randomized study with 116 healthy people
• Reissig CJ et al., J Clin Psychopharmacol 2026 – pilot study on effects, safety and pharmacokinetics of kratom in 40 participants
• Garcia-Romeu A et al., Drug Alcohol Depend 2020 – survey of 2,798 kratom users
• Olsen EO et al., MMWR 2019 – overdose deaths with kratom detected in 27 US states
• BfArM, press release 09/25 of July 1, 2025 – BfArM warns against the use of kratom
• BfArM, Joint Expert Commission for the Classification of Substances – minutes of the 36th meeting (kratom, BtMG, Czechia)
• BfArM, Joint Expert Commission for the Classification of Substances – minutes of the 41st meeting (October 19, 2026)
• EMCDDA (EUDA) – drug profile kratom
• DEA, Federal Register 91 (197) of October 14, 2026 – notice of intent to temporarily place 7-OH and mitragynine pseudoindoxyl in Schedule I