Ashwagandha vs Caffeine

for strength

Stronger evidence: tie

Stronger effect: Caffeine

Safety: Ashwagandha has the more serious interaction profile (moderate vs minor).

For strength, the two are evidence-matched; the difference is in effect and safety.

Ashwagandha

grade B moderate certainty

Ashwagandha supplementation was more efficacious than placebo for improving strength/power variables in healthy individuals.

Caffeine

grade B high certainty

reliable ergogenic effect on power and endurance performance

3–6 mg/kg pre-exercise, exercising adults
sources: PMID:33670194 · PMID:20000114