Kratom explained: what the leaf is, how lab-made versions differ and what the evidence shows on risk

Four deaths in Utah have been linked to potent semi-synthetic kratom compounds, state officials said Monday, October 5. Semi-synthetic means made in a laboratory by altering a natural compound. The products involved were not labeled as kratom. Some were sold as cat’s claw, an unrelated and harmless herb.

The case shows how far the word kratom now stretches. It covers a leaf that people in Southeast Asia have chewed for centuries, a powder sold in American convenience stores, and a growing family of laboratory-altered chemicals that behave like strong opioids. The risks of these things are not the same, and most of the data do not tell them apart.

This explainer sets out what kratom is, what the newer products are, and what the evidence shows about harm from each.

What kratom is

Kratom is a tree, Mitragyna speciosa, native to Thailand, Malaysia and Indonesia. Botanically related to coffee, kratom thrives in wetland areas. In its home region, fresh leaves were chewed to stave off fatigue among laborers or brewed into teas to relieve pain, diarrhea, and fever.

It reached the West recently. Kratom began appearing in U.S. markets in the late twentieth century, and sales grew after the mid-2000s. Outside its home region it is commonly consumed by preparing the leaves into decoction or tea, or by grinding them into a powder, a decoction being a boiled extract.

It is sold mainly for self-treatment. A review of concentrated kratom products published in Pharmaceutical Biology notes that marketing emphasizes pain, anxiety, low mood, fatigue and withdrawal from opioids.

Neither the leaf nor its derivatives have official approval. Kratom is not approved by the Food and Drug Administration, which says kratom is not appropriate for use as a dietary supplement.

What kratom does in the body

The leaf contains more than 40 alkaloids, the class of plant chemicals that also includes caffeine and morphine. The major constituent is mitragynine, which makes up between 12% and 66% of the total depending on where and how the plant was grown.

The effects depend on dose. The review describes them as stimulant-like at low doses and sedative/analgesic at higher doses, analgesic meaning pain-relieving. An earlier review put it more directly: kratom has physiological effects similar to opioids, including pain relief and euphoria, as well as stimulant properties.

The opioid-like action comes from the way kratom’s alkaloids attach to the mu-opioid receptor, the same docking point on nerve cells that morphine and heroin use. Mitragynine does this weakly. A second alkaloid does it strongly, and it is the source of the present concern.

How 7-OH products differ from kratom leaf

That second alkaloid is 7-OH, the short name for 7-hydroxymitragynine. The body makes some of it when it breaks down mitragynine. In the plant there is almost none: 7-OH generally constitutes <2% of the total alkaloid content in kratom leaves and products, and is not measurable in fresh leaves at all.

That scarcity is what kept traditional use relatively mild. Kratom has traditionally been consumed as fresh leaves or teas, and under those conditions exposure to 7-OH is minimal, because it occurs only at trace levels in leaf material.

The new products remove that limit. By contrast, the U.S. market offers chemically enriched or semi-synthetic 7-OH products, the review states. Here the starting material is mitragynine extracted from leaf, which is chemically oxidized to make 7-OH.

	Kratom leaf	Concentrated 7-OH products
Source	Dried or fresh leaf	Leaf extract altered in a laboratory
7-OH content	Trace	High, in some cases nearly pure
Typical forms	Powder, capsules, tea	Tablets dissolved under the tongue, gummies, liquid shots, nasal sprays
On the US market since	Late 1990s	About 2024
Main documented concern	Dependence, agitation, rare liver injury	Opioid-type overdose and withdrawal

They arrived fast. Explicitly labeled products appeared on vendor sites in approximately 2024 and expanded through early 2025. An independent team audited what was on sale and found 304 products, most of them containing 7-OH alone and formulated as chewable/sublingual tablets, shots, or gummies. Sublingual means dissolved under the tongue, a route that carries a drug into the blood without passing through the liver first.

The same audit looked at how they were sold. Functional claims of pain and anxiety relief were made by more than a third of products. Several products had names alluding to prescription opioids. The mean cost per recommended dose/serving was $3.97. Nine in ten of the 7-OH products were advertised as kratom.

In animals the compound behaves as a strong opioid. 7-OH shows multifold greater potency than morphine in tests of pain relief. Respiratory depressant action, a sentinel opioid toxicity, has been documented for 7-OH in animal studies, meaning that it slows breathing, which is how opioid overdoses kill.

The review’s conclusion is that concentrated 7-OH products are pharmacologically and toxicologically distinct from kratom leaf.

How many people use kratom

Kratom use is uncommon but not rare. An analysis of the 2019 national drug survey estimated that 0.7% of individuals in the U.S. have used kratom in the past year. A more recent figure comes from a different survey: the National Survey on Drug Use and Health reported 1.6 million adults used kratom in 2023, the review notes.

Kratom use clusters among people with a history of opioid problems. In the 2019 data, kratom use was particularly prevalent among those with prescription opioid use disorder, about one in ten of whom reported it. That fits the account many users give, of taking kratom to come off stronger drugs. It also means kratom users are more likely than average to be taking other substances, which complicates every statistic on harm.

How much of that use now involves concentrated products is unknown. The authors point out that these surveys do not distinguish botanical kratom from semi-synthetic 7-OH.

What the evidence shows on harms from kratom leaf

The clearest record comes from calls to poison centers, which log cases when a member of the public or a clinician phones for advice. From 2011 through 2017, 1807 kratom exposures were reported in the United States. Almost two-thirds (65.0%) of these exposures occurred during the last two years of that period, a sign of rapidly growing use.

Many cases were not trivial. About a third ended in admission to a health care facility. The most common clinical effects were agitation/irritability (22.9%) and tachycardia (21.4%), tachycardia being a fast heart rate.

Deaths were few and mostly involved other drugs. There were 11 deaths associated with kratom exposure, including two that occurred after exposure to kratom only. Cases that also involved other substances had roughly twice the odds of a serious outcome.

Dependence shows up in the same records in an unexpected place. There were seven neonatal exposures, including five experiencing withdrawal. These were newborns whose mothers had used kratom during pregnancy.

The potential for dependence has been recognized for a long time in the countries where the tree grows. It led to kratom’s categorization as a banned substance in both Malaysia and Thailand in the mid-twentieth century.

Liver injury has also been reported with kratom. The review judges those reports to be heterogeneous, often idiosyncratic, and frequently confounded by multi-ingredient products or co-exposures. In plainer terms, the cases vary, cannot be predicted from dose, and are often muddied by other ingredients or other drugs.

Poison-center counts have a known weakness. They capture only cases someone chose to report, and they say nothing about how many people used kratom without incident.

What is known about harms from 7-OH kratom products

For the concentrated products the record is shorter and comes mainly from state health departments. State health departments have reported severe intoxications and fatalities, the review notes.

In Texas, as of August 27, 2025, the Texas Poison Center Network had documented 192 exposures involving kratom or products containing 7-OH, already surpassing totals for all of 2024 (107) and 2023 (122).

In Pennsylvania, a summary of kratom and 7-OH cases from 2022 to mid-2025 found that naloxone was administered in 25 cases, and 14 required mechanical ventilation, although no deaths were reported. Mechanical ventilation is a machine that breathes for the patient. Naloxone is the drug that reverses an opioid overdose. Its use is a marker that clinicians were treating these patients as opioid poisonings.

In Los Angeles County, a health alert in September 2025 described fatal overdoses. At least three fatalities were explicitly attributed to 7-OH, often in conjunction with alcohol use.

Individual cases show how dependence can develop. One report described a 38-year-old man who moved from kratom capsules to 7-OH tablets bought at gas stations, and whose use escalated to as many as eight 30-mg tablets every one to two hours, about 240 mg a day by the review’s reckoning. When he stopped, he developed the symptoms of opioid withdrawal.

Availability is part of the picture. Clinical case documentation describes ready access to 7-OH tablets at gas stations and smoke shops.

The lab-made kratom compounds linked to the Utah deaths

The chemistry has not stopped at 7-OH. The two compounds named by Utah officials are further modifications of kratom’s main compounds, one of them called MGM-15. They were recently classified by the Drug Enforcement Administration as Schedule 1 drugs, the most restricted category in federal law.

In Utah they turned up under another plant’s name. According to the state’s warning, the compounds were found in certain herbal supplements, including products labeled as cat’s claw, a South American vine with no opioid activity. “These cat’s claw products contain dangerous opioids derived from kratom,” said Michael Moss, medical director of the Utah Poison Control Center.

Poison-center staff noticed the pattern before the deaths were tallied. Callers who had taken cat’s claw products were not describing the mild effects of that herb. People were instead reporting symptoms that resemble opioid overdoses. Other states have seen the same thing. Tennessee issued its own warning in September.

How kratom is regulated

Kratom leaf sits in a gap in American law. The Drug Enforcement Administration (DEA) moved toward banning it once and stepped back. The earlier review records the proposed categorization of kratom as a Schedule I drug by the US Drug Enforcement Administration (DEA) in 2016, which did not go ahead. Since then a handful of states have banned it on their own, and it remains legal in the rest.

The authors of the 7-OH review argue that regulators need to distinguish clearly between botanical kratom and high-potency, non-botanical opioids derived from the kratom scaffold, scaffold meaning the chemical skeleton of kratom’s main compounds. They favor tight controls on the concentrated products and lighter consumer-protection rules for leaf, such as age limits and accurate labeling.

They also warn against moving too abruptly. Abrupt removal of concentrated 7-OH from retail channels risks precipitating withdrawal among current users, they write, and could push people toward illicit sources.

What is not known about kratom

The basic numbers are missing. Population-level data specific to 7-OH remain limited. Nobody can say how many people use concentrated products, how often they are harmed, or how the risk compares with leaf.

Past records may understate the problem. The review notes that earlier surveillance rarely assayed for 7-OH specifically, assayed meaning tested, so some poisonings and deaths recorded as kratom may have involved concentrated products, and others may have been missed.

There are no clinical trials. Whether kratom leaf helps with pain or with opioid withdrawal, as many users believe, has not been tested in the way a medicine would be. Most of what is known about 7-OH comes from animal experiments and case reports.

The main review this article draws on is a narrative one. Its authors selected and interpreted the literature without the formal search and grading of a systematic review, and it leans heavily on a federal assessment and on state health alerts.

Products change faster than the research. The compounds linked to the Utah deaths were barely described in the scientific literature a year ago.

Kratom leaf has a documented record of dependence and poisonings, usually alongside other drugs, while the concentrated 7-OH products and newer derivatives sold under or near its name act as strong opioids and have been tied to deaths, on evidence that is still mostly case reports and state alerts.