What kind of drug is kratom classified as? An exploration of its dual pharmacological nature

October 11, 2025 •

5 min read

In Southeast Asia, the coffee-related tree Mitragyna speciosa has been used for centuries, producing effects that vary dramatically with dosage. Understanding what kind of drug is kratom classified as is complex because its active compounds act on both opioid and adrenergic systems, creating a dual pharmacological profile that defies simple categorization.

Quick Summary

Kratom is a botanical supplement with a dual-action profile, acting as both a stimulant and possessing opioid-like properties due to its main alkaloids, mitragynine and 7-hydroxymitragynine. It is not a federally controlled substance in the U.S. but is considered a Drug of Concern by the DEA, with its legal status varying by state and locality.

Key Points

Dual Action: Kratom is not classified solely as one type of drug; it has dose-dependent effects, acting as a stimulant at low doses and exhibiting opioid-like properties at higher doses.
Atypical Opioid: The primary alkaloids, mitragynine and 7-hydroxymitragynine, are considered atypical opioids because they activate mu-opioid receptors differently than classic opioids like morphine.
Reduced Respiratory Risk: Unlike classic opioids, kratom's alkaloids do not recruit the beta-arrestin pathway, which may explain the lower risk of respiratory depression associated with its use, though it can still be dangerous, especially when combined with other drugs.
Uncontrolled Federally: At the federal level in the U.S., kratom is not a controlled substance under the CSA, but the DEA lists it as a "Drug and Chemical of Concern".
Variable Legality: Kratom's legal status is inconsistent across the United States, with some states and localities having banned it while others have implemented regulations like age restrictions.
Unapproved by FDA: The FDA has not approved kratom for any medical use and warns against its consumption due to safety and efficacy concerns.

The Dual Nature of Kratom

Kratom, derived from the leaves of the Mitragyna speciosa tree, presents a unique challenge to drug classification due to its dose-dependent effects. At low doses, kratom's alkaloids produce stimulating, energizing effects similar to a stimulant, including increased alertness and talkativeness. At higher doses, however, the effects shift to resemble opioids, inducing sedation, euphoria, and analgesia (pain relief). This unusual combination of stimulant and opioid-like activity stems from the complex interaction of its active compounds with multiple neurotransmitter systems.

The Pharmacology Behind Kratom's Classification

The dual pharmacological effects of kratom are primarily mediated by two key indole alkaloids: mitragynine and its metabolite, 7-hydroxymitragynine. These compounds act on the brain's opioid receptors, but their molecular structure and mechanism of action are distinct from classic opioids like morphine or heroin.

Key Active Alkaloids: Mitragynine and 7-Hydroxymitragynine

Mitragynine: The most abundant alkaloid in kratom, mitragynine acts as a partial agonist at the mu-opioid receptor. It is also known to interact with other receptors, including adrenergic and serotonin receptors, which contributes to its stimulant-like effects at lower doses. Its metabolism in the liver produces 7-hydroxymitragynine.
7-Hydroxymitragynine: While present in much smaller quantities in the plant, this metabolite is significantly more potent than mitragynine and morphine at the mu-opioid receptor. It is believed to be responsible for much of kratom's opioid-like effects.

How Kratom Differs from Classic Opioids

One of the most important pharmacological differences between kratom's alkaloids and classic opioids is their interaction with the beta-arrestin pathway. While both bind to mu-opioid receptors, kratom's compounds do not initiate the beta-arrestin signaling pathway, which is heavily implicated in causing serious adverse effects associated with opioids, such as respiratory depression, sedation, and constipation. This mechanism suggests a potential for a better side effect profile, although kratom can still cause respiratory depression at high doses, especially when combined with other substances.

Uses of Kratom

Historically and presently, kratom is used for various purposes:

In Southeast Asia, manual laborers traditionally chew the leaves for increased energy and endurance to combat fatigue.
Some people use kratom to self-treat chronic pain, anxiety, and depression.
A growing number of individuals use it to manage symptoms of opioid withdrawal and to aid in reducing or stopping opioid use, though the FDA has not approved this use.
Recreational use is common for its euphoric effects, especially at higher doses.

Potential Health Risks and Adverse Effects

Despite a different mechanism of action than classic opioids, kratom use is not without risks, which can vary depending on the dose, potency, and combination with other substances. Some common side effects include nausea, constipation, dizziness, and dry mouth. More serious and rare adverse effects have also been reported:

Psychiatric symptoms, including hallucinations and psychosis, particularly with long-term, high-dose use.
Cardiovascular issues, such as rapid heartbeat.
Gastrointestinal problems, including liver toxicity.
Neurological effects like tremors and seizures.
Risk of neonatal abstinence syndrome in newborns of mothers who use kratom.

Comparison of Kratom vs. Classic Opioids


Feature	Kratom (Mitragynine)	Classic Opioids (e.g., Morphine)
Mechanism	Partial agonist at mu-opioid receptors, interacts with other systems (adrenergic, serotonin); does not recruit beta-arrestin.	Full agonists at mu-opioid receptors; recruits beta-arrestin.
Dose-Dependent Effects	Stimulant-like at low doses; opioid-like at high doses.	Sedative and analgesic effects at all active doses.
Respiratory Depression	Low to negligible risk with kratom alone, but can occur with high doses or in combination with other depressants.	Significant and potentially fatal risk, especially with overdose.
Abuse Potential	Can lead to physical dependence and withdrawal, but often reported as milder and easier to manage than opioid addiction.	High potential for addiction, dependence, and severe withdrawal symptoms.
Overdose Risk	Lower risk compared to classic opioids when used alone, but high risk when mixed with other substances.	High risk of fatal overdose, primarily due to respiratory depression.
Legality	Unscheduled federally in the U.S., but often regulated at the state/local level; listed as a Drug of Concern by the DEA.	Schedule I or II controlled substances under the CSA, tightly regulated.

The Current Legal Status and Regulation Challenges

For many, kratom's classification is complicated not just by its pharmacology but by its inconsistent legal status. At the federal level in the United States, kratom is not a controlled substance under the Controlled Substances Act (CSA), despite the DEA previously attempting to place its active ingredients in Schedule I in 2016. The FDA, however, has not approved kratom for any medical use and warns against its use due to safety concerns and potential for dependence.

Federal Status in the U.S.

The DEA lists kratom as a Drug and Chemical of Concern, signaling potential risks but without imposing strict federal controls. The FDA has taken action by issuing import alerts for kratom products and seizing products that are unlawfully marketed as dietary supplements or food additives, citing safety and efficacy concerns. The lack of federal scheduling allows for a patchwork of state and local regulations to exist.

State and Local Regulations

State-level regulation of kratom varies dramatically. Some states have passed the Kratom Consumer Protection Act (KCPA) to regulate the product's sale, requiring manufacturers to meet certain standards for labeling and purity. Other states and municipalities have banned kratom entirely. This diverse regulatory landscape means kratom's legal status is highly dependent on one's geographic location.

Conclusion

In conclusion, asking what kind of drug is kratom classified as reveals a complex pharmacological profile that positions it uniquely between stimulants and opioids. Its dual effects, mediated by mitragynine and 7-hydroxymitragynine, and its distinct lack of beta-arrestin recruitment set it apart from classic opioid narcotics, offering a different risk/benefit ratio. While many users report perceived therapeutic benefits, particularly for pain and opioid withdrawal, kratom is not an FDA-approved medication and carries documented risks, including dependence and severe side effects. The legal situation in the United States remains inconsistent, with federal agencies expressing concern while states implement a range of regulatory approaches from outright bans to consumer protection standards. The ongoing debate highlights the need for further controlled scientific research to fully understand its safety and efficacy.

For more research-based information, visit the National Institute on Drug Abuse (NIDA) website on Kratom.

Frequently Asked Questions

No, kratom is not a controlled substance under the federal Controlled Substances Act (CSA) in the United States. However, its legal status can vary greatly at the state and local levels, where some jurisdictions have banned or regulated it.

Kratom's primary alkaloids, mitragynine and 7-hydroxymitragynine, bind to the brain's mu-opioid receptors, which is the same type of receptor targeted by opioid drugs. Mitragynine also interacts with other brain systems, including adrenergic, serotonin, and dopamine receptors, which contributes to its stimulant-like and mood-altering effects.

Kratom produces dose-dependent effects. At low doses, it acts as a stimulant, increasing alertness and energy. At higher doses, its opioid-like properties become dominant, leading to sedation, euphoria, and pain relief.

Kratom can be dangerous, especially at high doses or when mixed with other substances. The FDA warns against its use due to risks including liver toxicity, seizures, and the potential for substance use disorder. While the risk of respiratory depression is lower than with classic opioids, it is not zero.

Yes, chronic, regular use of kratom can lead to physical dependence and addiction. When regular users attempt to quit, they may experience withdrawal symptoms, though many reports suggest these are milder and more manageable than those associated with classical opioids.

Regulation is inconsistent. Federally, the FDA has not approved it for any medical use and restricts its marketing as a dietary supplement or food additive. At the state and local levels, some jurisdictions have banned it, while others have adopted consumer protection laws that regulate its sale, such as age restrictions and labeling standards.

No, kratom products can vary widely in potency (the concentration and strength of their active compounds) and may contain contaminants, including heavy metals or bacteria, as they are not subject to federal safety or quality control standards.