A worker checks a sample of ground kratom leaves at a facility in West Kalimantan, Indonesia. The leaves of the kratom tree have long been used as a mild stimulant and for medicinal purposes in Southeast Asia—but experts warn that supplements derived from the plant and sold in the U.S. can have very different properties.Sourced from an Asian tree’s leaves, kratom produces weak opioid-like effects.
Underlying this uncertainty is a lack of peer-reviewed research. “We really don’t have a scientific understanding of the safety or the efficacy of the product,” says Christopher McCurdy, a professor of medicinal chemistry at the University of Florida who has studied kratom use for over a decade.
Another key compound is alkaloid 7-hydroxymitragynine, which has far more potent opioid-like impacts. Kratom plants contain very small amounts of 7-hydroxymitragynineKratom also binds to serotonin receptors, which regulate mood and anxiety, and it impacts dopamine release. These systems can also help reduce pain, McCurdy says—making it difficult to parse out which compounds are really at work. “We just don’t understand exactly how they are playing together,” he says.
C. Michael White, a distinguished professor of pharmacy practice at the University of Connecticut, agrees. “Data on kratom use for anxiety, for alertness, to reduce fatigue, or any other purpose is very scant,” he says. Dried leaf material sold in capsules or bulk powder, used to make teas or just consumed whole, tends to be less potent, McCurdy notes. Other kratom supplements are made from leaves that have been processed, refined, or manipulated to produce extract products that deliver a higher chemical dose with a higher risk of negative effects.
“You start out voluntarily taking it, but at a certain point you need to take it just to feel regular,” White says. “Then if you don’t take it instead of going back to your normal state you feel worse.”