Comparison
Ashwagandha vs Tribulus Terrestris
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.
Tribulus Terrestris
Mediterranean and Indian herb traditionally used for libido and athletic performance. Evidence is mixed; the testosterone-raising claims are mostly unsupported.
| Field | Ashwagandha | Tribulus Terrestris |
|---|---|---|
| Category | adaptogen | adaptogen |
| Dose range | 300–600mg | 250–750mg |
| Half-life | 6h | — |
| Onset | — | — |
| Evidence | EVIDENCEA | EVIDENCEB |
| Safety | ●●●●● | ●●●●○ |
| Legal (US) | USOTC | USOTC |
| PubMed refs | 650 | 320 |
The comparison in plain English
Auto-generated from dataAshwagandha and Tribulus Terrestris are both in the adaptogen category respectively. Ashwagandha Withania somnifera, the most clinically validated herbal adaptogen for stress and anxiety. Tribulus Terrestris Mediterranean and Indian herb traditionally used for libido and athletic performance.
Bottom line
Ashwagandha (evidence A, safety 5/5) has a weaker evidence base than Tribulus Terrestris (evidence B, safety 4/5). 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 Tribulus Terrestris if
Tribulus Terrestris is the better fit when your goal aligns with its mechanism (Contains steroidal saponins (protodioscin and related compounds) that have been hypothesised to modulate testosterone, LH, and DHEA — but multiple well-designed RCTs have failed to confirm testosterone elevation in healthy young men) and the dose range (250–750mg) suits your protocol. Half-life is —h.