Kratom is the common name for Mitragyna speciosa, a tropical tree native to Southeast Asia. Its leaves contain more than 40 alkaloids, two of which interact with the mu-opioid receptor system: mitragynine and 7-hydroxymitragynine (7-OH). Kratom is sold in many forms in the United States and is not FDA-approved for any medical use.
What is kratom?
Kratom is the leaf of Mitragyna speciosa, a tropical evergreen tree in the coffee family (Rubiaceae) native to Southeast Asia. The leaves contain more than 40 active alkaloids. The two that matter most clinically are mitragynine, the most abundant alkaloid in the leaf, and 7-hydroxymitragynine, often called 7-OH.
Kratom leaves have a long history in Thailand, Malaysia, Indonesia, and other parts of Southeast Asia, where they have been chewed or brewed into tea. In the United States, kratom is sold widely as a supplement-style product but is not approved by the U.S. Food and Drug Administration for any medical purpose (FDA).
Where does the name Mitragyna speciosa come from?
Mitragyna is the genus and speciosa is the species. The genus name was given by Dutch botanist Pieter Willem Korthals in the 1800s. It comes from Greek roots referring to the shape of the plant's stigma — the part of the flower's reproductive organ — which Korthals described as resembling a mitra, a pointed cap or bishop's miter.
| Taxonomy | |
|---|---|
| Family | Rubiaceae (the coffee family) |
| Genus | Mitragyna |
| Species | speciosa |
| Scientific name | Mitragyna speciosa |
| Common name | Kratom |
How are kratom and 7-OH connected?
7-OH occurs naturally in kratom leaf in very small amounts — often less than 0.05% of the leaf's dry weight, per FDA's 7-OH scientific assessment. When kratom is consumed, the human body also produces a small additional amount of 7-OH as an active metabolite of mitragynine, through a liver enzyme called CYP3A4 (Kruegel et al., ACS Cent. Sci. 2019).
Despite being present in only small amounts in plain leaf, 7-OH is much more potent at the mu-opioid receptor than mitragynine and is believed to account for much of kratom's opioid-like effects. This natural relationship matters for one main reason: manufacturers have begun isolating or synthesizing pure 7-OH, separating it from the rest of the plant and selling it in concentrated forms. These concentrated 7-OH products contain 7-OH in amounts far beyond what occurs naturally, and they behave very differently at the bedside.
What forms is kratom sold in?
In the United States, kratom is sold in many forms — in smoke shops, gas stations, vape shops, and online. The same plant, sold in these very different forms, can produce very different exposures to the active alkaloids.
- Dried leaf powder
- Capsules
- Teas, decoctions, or brewed beverages
- Liquid "shots"
- Full-spectrum extracts
- Gummies and dissolvable tablets
- Concentrated or enhanced 7-OH products (clinically distinct — see below)
Is kratom FDA-approved?
No. Kratom is not approved by the U.S. Food and Drug Administration for any medical use, including for the treatment of opioid use disorder. FDA has issued multiple consumer warnings about kratom and has specifically warned about products containing added or enhanced 7-hydroxymitragynine.
- U.S. Food and Drug Administration — FDA and Kratom.
- U.S. Food and Drug Administration — Products Containing 7-OH Can Cause Serious Harm.
- Kruegel AC, Uprety R, Grinnell SG, et al. 7-Hydroxymitragynine Is an Active Metabolite of Mitragynine and a Key Mediator of Its Analgesic Effects. ACS Central Science 2019. Article link.
- World Health Organization — 44th ECDD Pre-Review of Kratom.
Last reviewed: May 2026 · Reviewed by: MyStreetHealth Medical Team
