Comparison
Ashwagandha vs Kanna
Ashwagandha
Withania somnifera, the most clinically validated herbal adaptogen for stress and anxiety. Reduces serum cortisol by roughly 28% at 600 mg/day over 8 weeks. Modest evidence for sleep quality and testosterone in men. Choose the KSM-66 extract for the best-studied form.
Kanna
Sceletium tortuosum — South African succulent. Acts as serotonin reuptake inhibitor and PDE4 inhibitor.
| Field | Ashwagandha | Kanna |
|---|---|---|
| Category | adaptogen | adaptogen |
| Dose range | 300–600mg | 25–50mg |
| Half-life | 6h | — |
| Onset | — | — |
| Evidence | EVIDENCEA | EVIDENCEB |
| Safety | ●●●●● | ●●●○○ |
| Legal (US) | USOTC | USOTC |
| PubMed refs | 650 | 50 |
The comparison in plain English
Auto-generated from dataAshwagandha and Kanna are both in the adaptogen category respectively. Ashwagandha Withania somnifera, the most clinically validated herbal adaptogen for stress and anxiety. Kanna Sceletium tortuosum — South African succulent.
Bottom line
Ashwagandha (evidence A, safety 5/5) has a weaker evidence base than Kanna (evidence B, safety 3/5). Ashwagandha has the slightly cleaner safety profile. For users new to either, the higher-evidence option is the safer first try.
Choose Ashwagandha if
Ashwagandha is the better fit when your goal aligns with its mechanism (Withanolides modulate GABA-A receptors and blunt the HPA-axis cortisol response) and the dose range (300–600mg) suits your protocol. Half-life is 6h.
Choose Kanna if
Kanna is the better fit when your goal aligns with its mechanism (Mesembrine and related alkaloids inhibit serotonin reuptake (similar to SSRI mechanism but at much lower potency) and PDE4 (similar to rolipram)) and the dose range (25–50mg) suits your protocol. Half-life is —h.