NIH Gets Green Light for First Human Trial of Kratom Compound Against Opioid Use Disorder

The FDA just cleared an Investigational New Drug application for mitragynine — the primary psychoactive compound in kratom — enabling the first human trial to evaluate it as a treatment for opioid use disorder. That IND, announced by NIH on June 1, 2026, moves a purified formulation from the lab into a phase I safety study.

What the IND Actually Opens

An IND means NIH can now legally ship a drug candidate across state lines and dose humans in a controlled setting. For mitragynine, that's the culmination of years of preclinical work by researchers at NIH’s National Center for Advancing Translational Sciences (NCATS), the National Institute on Drug Abuse (NIDA), and the University of Florida. They developed the purified formulation and ran animal studies showing “no significant safety concerns” across multiple doses.

Kratom has a messy reputation — it’s a Southeast Asian tree whose leaves are sold as supplements, but its opioid-like effects have drawn both FDA warnings and grassroots claims of withdrawal relief. The key insight from the NIH team: the plant’s therapeutic potential likely comes from the slow conversion of mitragynine in the body, not from the leaf cocktail itself.

Why Mitragynine, Not Kratom

Crude kratom contains dozens of alkaloids, some of which interact with opioid receptors in ways that can cause dependence or respiratory depression. Isolating mitragynine lets researchers separate the signal from the noise. The purified compound hasn’t been studied in humans until now — this IND changes that.

Nora Volkow, director of NIDA, called it “a major step toward expanding treatment options for the millions of Americans struggling with opioid use disorder.” That’s not PR fluff. Overdose mortality is historically high, and existing treatments (methadone, buprenorphine, naltrexone) have access and adherence problems.

What the Phase I Trial Looks Like

NIH scientists plan a randomized, double-blind, placebo-controlled study — the gold standard for early safety. Primary endpoints: safety and tolerability. No efficacy hunting yet. That’s how you build a regulatory path for a compound that’s been used recreationally for decades without any controlled human data.

NCATS Director Joni Rutter: “We’ve seen the potential of mitragynine in the lab, and now we’re finally able to examine its potential in people.” The trial falls under the NIH HEAL Initiative, the agency’s long-term push to curb the opioid crisis.

What This Enables Next

If phase I shows mitragynine is safe in humans at relevant doses, the next step is phase II efficacy trials — comparing it head-to-head against standard-of-care for withdrawal or maintenance. The IND structure also means NIH controls the purity, dosing, and route of administration, avoiding the variability of off-label kratom use.

For the millions who’ve self-medicated with kratom powder from head shops, this trial is the first real chance to find out whether the compound actually works — and at what cost.

Source: NIH research clears way for study of experimental treatment for opioid use disorder
Domain: nih.gov