The Herbarium · Roots & botanicals
Kanna
Sceletium tortuosum · succulent botanical
A small succulent. A distinct botanical path.
Plant wisdom · evidence at a glance
Potential benefits
What researchers have found, how strong the evidence is, and where questions remain. Findings apply to the preparation studied—not automatically to products on our shelves.
Early human research · small study
Cognitive flexibility & executive function
A crossover trial with 21 healthy adults reported improvements on selected cognitive tests with a particular standardized kanna extract. This is preliminary evidence for that preparation, not proof that every kanna product improves memory or prevents cognitive decline.
Early human research · brain-imaging outcome
Stress-response pathways
A small experimental study found changes in brain responses to threat after a standardized extract. Brain-imaging changes are not the same as demonstrated relief from an anxiety or depressive disorder.
Open the field notes
Kanna refers to Sceletium tortuosum, a South African succulent with a history of use by Indigenous communities. It is a different plant from kava, and it is not a cannabinoid. Its story belongs on its own shelf in the Herbarium.
On the apothecary shelf
Modern kanna products may use standardized extracts or other preparations. Look for the botanical name, the type of extract, and the amount per serving. An extract's milligram weight does not, by itself, tell you its alkaloid content or make it equivalent to another product.
Into the research library
Follow the scholarship behind the curiosity. These peer-reviewed papers examine specific ingredients or preparations—not TOP products. Human trials, research reviews, and preclinical studies answer different questions. A link is not a promise of benefit or a recommendation to treat a condition.
Human randomized safety trial
Standardized kanna extract in healthy adults ↗Nell H et al. · J Altern Complement Med · 2013 Nov · PMID 23441963
Human experimental neuroimaging study
Kanna extract and amygdala responses ↗Terburg D et al. · Neuropsychopharmacology · 2013 Dec · PMID 23903032
Small human randomized crossover trial
Kanna extract and cognitive test performance ↗Chiu S et al. · Evid Based Complement Alternat Med · 2014 · PMID 25389443
Peer-reviewed research review
Kanna chemistry, pharmacokinetics, and clinical research ↗Olatunji TL et al. · J Ethnopharmacol · 2021 Nov 15 · PMID 34333104
Read each paper's methods, limitations, funding, and conflict-of-interest disclosures. Animal and cell findings do not establish benefits in people; a review may include the same trials as another review. PubMed links provide abstracts and full-text links where available.
Sources & further reading
Kew: Sceletium tortuosum ↗ Human study of a standardized kanna extract ↗These independent references inform our educational notes. They are not endorsements of TOP or of any product. Notes reviewed October 31, 2026.
For adults 21+. Educational information, not medical advice. Our team can help you read labels and locate lab reports. A qualified health professional should advise on medicines, health conditions, pregnancy, or breastfeeding. Ask a veterinarian before using any product with a pet. Availability varies; an educational page does not mean an ingredient is currently in stock.