Caffeine vs Ashwagandha
for energy / fatigue
Stronger evidence: tie
Stronger effect: tie
Safety: Ashwagandha has the more serious interaction profile (minor vs moderate).
For energy / fatigue, the two are evidence-matched; the difference is in effect and safety.
Caffeine
grade B moderate certainty
reduces perceived fatigue; tolerance develops with regular use
40–200 mg
Ashwagandha
grade B moderate certainty
Ashwagandha supplementation was more efficacious than placebo for improving fatigue/recovery variables in healthy individuals.
sources: PMID:00000021 · PMID:33670194