Kanna and Cognition: What Small Studies Can Tell Us

TL;DR: The research on kanna and thinking is small and early, and almost all of it used one branded extract, Zembrin, not the kanna products sold in shops. One 2014 study of 21 healthy adults saw better scores on cognitive flexibility and executive function tests, a 2013 brain scan study looked at 16 people, and a separate safety trial followed 37 adults for three months, which is interesting but nowhere near proof that any kanna product sharpens memory or focus.

We get asked about kanna and focus all the time, usually by someone who read a headline promising a sharper brain. So we went back to the actual studies. The honest answer is that the research is still preliminary. The small studies people point to were done on a particular branded extract called Zembrin, not on every product sold as kanna. Keep that in mind any time you read claims about focus or memory.

A small proof-of-concept study

A 2014 randomized, placebo-controlled crossover study involved 21 cognitively healthy people. Crossover means each person took both Zembrin and a placebo at different times, so they acted as their own comparison. After three week treatment periods, the researchers reported differences favoring Zembrin on measures of cognitive flexibility and executive function.

Those are specific test results from a small group. They're not proof of broad memory improvement, and they don't mean everyone will perform better in daily life. Read the cognition study by Chiu and colleagues.

Everyone in the study was cognitively healthy. The paper talks about possible directions for future research, but it doesn't establish kanna as a treatment for dementia or any other condition. It also doesn't show that Healing Herbals products have the same effects.

Brain scans answer a different question

A separate 2013 study of 16 healthy people looked at brain responses after a single dose of Zembrin. Brain imaging is useful research context. But a change on a scan is not the same thing as better memory, better concentration or getting more done at work. Read the brain-response study by Terburg and colleagues.

Safety studies aren't efficacy studies

A 2013 trial followed 37 healthy adults for three months to check the safety and tolerability of Zembrin. It didn't measure whether the extract did anything for thinking or mood. Results about tolerability in one defined group don't prove kanna is safe for everybody, and they don't prove a cognitive benefit either. Read the safety and tolerability trial by Nell and colleagues.

Why the exact preparation matters

A study only tells you about the preparation, the people, the length of time and the outcomes it actually tested. The products in our catalog were not tested in the studies above. A higher alkaloid percentage, a similar plant name or a different format doesn't make a product clinically equivalent to Zembrin.

We think that's worth saying plainly, even though we sell kanna. At the bar and the shop, people tell us all kinds of things about how kanna makes them feel, and we believe them. But how people feel and what a controlled study measured are two separate kinds of information, and we try not to blur them.

This overview doesn't recommend a dose, combining supplements or replacing prescribed treatment. It also doesn't rank kanna against other cognitive supplements, since that would take proper comparison studies that don't exist yet.

Read product information carefully

If you want help telling a label apart from research evidence, read our guide to total alkaloid percentages. Our botanical lab-report guide explains sample identity and what a test does and doesn't cover, and the kanna extract comparison guide walks through labels and formats.

Common questions

Has kanna been proven to improve memory?
No. One small study found better scores on a couple of specific tests using a branded extract. That's a start, not proof.

Were Healing Herbals products tested in these studies?
No. All three studies used Zembrin.

Does a safety study mean kanna is safe for everyone?
No. It means it was tolerated by that particular group of healthy adults over three months.

Research overview reviewed September 13, 2026. This is a focused summary of three studies, not a systematic review of all kanna research.