Kratom is a tropical tree native to Southeast Asia whose leaves contain compounds that interact with opioid receptors in the brain, producing effects that range from mild stimulation at low doses to sedation and pain relief at higher doses. The tree has been used for centuries in countries like Thailand and Malaysia, where workers traditionally chewed the leaves to fight fatigue and boost productivity. In the West, it’s sold as a powder, capsule, or tea and has gained popularity as a self-treatment for chronic pain and opioid withdrawal, though it carries real risks and remains unregulated by the FDA.
The Plant Itself
Kratom’s scientific name is Mitragyna speciosa, and it’s a small-to-medium sized tree in the coffee family. It grows naturally in the tropical climates of Southeast Asia, where indigenous communities have used it as an ethnobotanical medicine for generations. Traditional uses included relieving pain, treating diarrhea, and helping people endure long hours of physical labor. The leaves were typically chewed fresh or brewed into tea.
Today, kratom leaves are harvested, dried, and ground into a fine powder for export. That powder is then sold in bulk bags, brewed as tea, packed into capsules, or occasionally smoked. Because the FDA does not regulate kratom as a food or drug, there’s no standardized preparation or dosing. The products you find online or in smoke shops can vary widely in potency and purity.
How It Works in the Body
Kratom leaves produce more than 40 structurally related alkaloids, but two get the most attention: mitragynine and 7-hydroxymitragynine. Both bind to the same brain receptors that opioid drugs like morphine target, specifically the mu-opioid receptor. But they behave differently than traditional opioids in important ways. Rather than fully activating these receptors, they act as partial agonists, meaning they trigger a weaker version of the response that drugs like morphine produce. They also don’t appear to recruit a signaling pathway (called beta-arrestin-2) that’s linked to some of the worst opioid side effects, including slowed breathing.
Several of kratom’s minor alkaloids also interact with opioid receptors. Some act on the mu receptor like the main alkaloids do, while at least one, isopaynantheine, targets a different opioid receptor (the kappa receptor) that influences mood and perception. In animal studies, some of these minor alkaloids produced pain relief without the respiratory depression or hyperactivity that morphine causes. This complex cocktail of compounds is part of why kratom’s effects feel different from pharmaceutical opioids, and why researchers are interested in it as a starting point for safer pain medications.
Stimulant at Low Doses, Sedative at High Doses
Kratom’s most distinctive feature is its dose-dependent flip. At low doses, roughly 1 to 5 grams of dried leaf powder, users typically report stimulant-like effects: increased energy, alertness, and sociability. This is the profile that Southeast Asian laborers relied on for centuries.
At higher doses, between 5 and 15 grams, the experience shifts toward sedation and pain relief. The opioid-like effects become more prominent, and users describe relaxation, euphoria, and reduced pain perception. This sedative range is where the risk of side effects climbs and where the potential for dependence becomes more significant. The exact threshold where stimulant turns to sedative varies from person to person and product to product, since alkaloid concentrations in commercial kratom are inconsistent.
Known Risks and Side Effects
The FDA has issued warnings against kratom use, citing risks of liver toxicity, seizures, and substance use disorder. At opioid-like doses, kratom can produce familiar opioid side effects: nausea, vomiting, constipation, sedation, and physical dependence. People who use kratom regularly can develop tolerance and experience withdrawal symptoms when they stop, including irritability, muscle aches, insomnia, and anxiety.
Respiratory depression, the leading cause of death in opioid overdoses, has also been reported with kratom, though it appears to be less common than with traditional opioids. Most kratom-associated deaths involve other substances, but fatalities linked to kratom alone have been documented. Liver injury is another concern. Some users develop signs of liver inflammation weeks after starting regular use, which typically resolves after stopping but can be serious.
Contamination Is a Real Problem
Because kratom is unregulated, commercial products face no mandatory testing for contaminants. This isn’t a theoretical concern. During a multistate outbreak in 2017 and 2018, 21 different strains of Salmonella were found in kratom products sold at retail locations and in patients’ homes. Testing during that investigation found Salmonella in half of the kratom samples collected. The contamination likely occurs during harvesting, processing, or storage in the countries where kratom is grown, similar to contamination patterns seen in imported herbs and spices. Heavy metals are another documented concern in unregulated botanical products, though testing data specific to kratom is more limited.
Legal Status in the United States
Kratom is not a controlled substance under federal law. The DEA considered emergency scheduling it in 2016 but backed off after public backlash and requests for more research. It remains on the DEA’s list of “Drugs and Chemicals of Concern,” and the FDA has not approved it for any medical use. The practical result is that kratom is legal to buy and sell in most of the country, but several states and cities have banned or restricted it. Alabama, Arkansas, Indiana, Rhode Island, Vermont, and Wisconsin have statewide bans. Some other states have passed the Kratom Consumer Protection Act, which keeps it legal but requires product labeling and testing standards.
This patchwork means your ability to legally purchase kratom depends entirely on where you live, and even in states where it’s legal, no federal agency is ensuring the product is safe, pure, or accurately labeled.
Why People Use It
The most common reasons people turn to kratom are chronic pain management and opioid withdrawal. For pain, it’s seen as a cheaper, more accessible alternative to prescription medications, especially for people without insurance or those who’ve been cut off from opioid prescriptions. For withdrawal, some people use kratom’s milder opioid-receptor activity to ease the transition off stronger drugs like heroin or prescription painkillers.
There’s a real tension here. Kratom’s alkaloids genuinely interact with opioid receptors and produce measurable effects, and some users report meaningful relief. But the lack of regulation means there’s no quality control, no standardized dosing, and no clinical trials proving it works for these purposes. You’re essentially self-medicating with a variable, unregulated product that carries its own dependence risk. Some researchers see kratom’s unique pharmacology, particularly its partial agonism and reduced respiratory depression, as promising leads for developing new medications. But the raw plant product and the purified, tested drug that might eventually come from it are very different things.