Supplement
Kanna is a succulent plant from southern Africa, traditionally chewed or brewed for its mood-lifting effects, and it contains alkaloids thought to act on the brain's serotonin system. People mostly look at it for dementia, and the evidence is limited: a small trial found cognition improved. Only a few small studies exist, with a handful of participants each, and one stress test found no clear difference in reaction time, so firm conclusions aren't possible yet.
- Updated
- How we grade
- 3 studies cited
- Best evidence
- Grade C
- Conditions studied
- 6
- Outcomes
- 28
- Graded outcomes
- 0051
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition Small Improvement | Improves (the measure goes up) | Small effect | 16 people | |||
| Executive Function Small Improvement | Improves (the measure goes up) | Small effect | 16 people | |||
| Sleep Quality | Improves (the measure goes up) | 1 study | 16 people | |||
| Stress Signs and Symptoms | Improves (the measure goes down) | 1 study | 15 people | |||
Studies that measured stress signs and symptoms | ||||||
| Memory | Improves (the measure goes up) | 16 people | ||||
| Reaction Time | Improves (the measure goes up) | 31 people | ||||
| Subjective Well-Being | Improves (the measure goes up) | 16 people | ||||
Alzheimer’s Disease
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition Small Improvement | Improves (the measure goes up) | Small effect | 16 people | |||
| Sleep Quality | Improves (the measure goes up) | 1 study | 16 people | |||
| Executive Function | Improves (the measure goes up) | 16 people | ||||
| Memory | Improves (the measure goes up) | 16 people | ||||
| Reaction Time | Improves (the measure goes up) | 16 people | ||||
| Subjective Well-Being | Improves (the measure goes up) | 16 people | ||||
Dementia
- Cognition: improves
- Sleep Quality: improves
- Executive Function: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition Small Improvement | Improves (the measure goes up) | Small effect | 16 people | |||
| Sleep Quality | Improves (the measure goes up) | 1 study | 16 people | |||
| Executive Function | Improves (the measure goes up) | 16 people | ||||
| Memory | Improves (the measure goes up) | 16 people | ||||
| Reaction Time | Improves (the measure goes up) | 16 people | ||||
| Subjective Well-Being | Improves (the measure goes up) | 16 people | ||||
Alzheimer’s Disease
- Cognition: improves
- Sleep Quality: improves
- Executive Function: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition Small Improvement | Improves (the measure goes up) | Small effect | 16 people | |||
| Sleep Quality | Improves (the measure goes up) | 1 study | 16 people | |||
| Executive Function | Improves (the measure goes up) | 16 people | ||||
| Memory | Improves (the measure goes up) | 16 people | ||||
| Reaction Time | Improves (the measure goes up) | 16 people | ||||
| Subjective Well-Being | Improves (the measure goes up) | 16 people | ||||
Stress
- Reaction Time
- Stress Signs and Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Reaction Time No effect | NoneNo effect | 15 people | ||||
| Stress Signs and Symptoms | Improves (the measure goes down) | 1 study | 15 people | |||
Studies that measured stress signs and symptoms | ||||||
Mood Improvement
- Heart Rate: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Heart Rate | Improves (the measure goes down) | 1 study | 37 people | |||
Studies that measured heart rate | ||||||
Key findings
- CognitionImproves (the measure goes up)
- Executive FunctionImproves (the measure goes up)
- Reaction Time
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- Grade C
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Studies cited
3 studies from PubMed
- A randomized, double-blind, parallel-group, placebo-controlled trial of Extract Sceletium tortuosum (Zembrin) in healthy adults
- Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in Cognitively Healthy Subjects: Implications for Alzheimer's Dementia
- Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdala and its connection to the hypothalamus