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Head-to-head evidence comparison — which supplement is right for you?
Ashwagandha and Caffeine are closely matched across evidence, studies, and safety.
Verdict
Likely helps
14 of 14 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
29 of 35 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Ashwagandha and Caffeine have evidence — compare verdict strength side-by-side.
300-600mg daily (standardized extract)
Morning for daytime stress, Evening for sleep support
KSM-66 or Sensoril standardized extract
100-200mg
Morning, 30-60 minutes before exercise
Pill/capsule for precise dosing
2-4 weeks
2-4 weeks
2-4 weeks
First week
15-45 minutes
30-60 minutes
30-60 minutes
30-60 minutes
Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis
Explore (NY) (2024) · Meta analysis · n=873
Significant effect on the Perceived Stress Scale (PSS) (MD = -4.72, 95 % CI = [-8.45 to -0.99]).
Effects of Withania somnifera Extract in Chronically Stressed Adults: A Randomized Controlled Trial
Nutrients (2024) · Rct · n=131
Our findings demonstrate the stress-reduction capabilities of this well-characterized aqueous extract of WS (root and leaf) at the low dose of 125 mg/day, in a dose-dependent manner, via the modulation of the HPA axis.
Plant-derived nootropics and human cognition: A systematic review
Critical reviews in food science and nutrition (2023) · Systematic review
Bacopa monnieri improves language, learning and memory.
Effect of Acute Caffeine Intake on the Fat Oxidation Rate during Exercise: A Systematic Review and Meta-Analysis
Nutrients (2020) · Meta analysis · n=2020
A subsequent meta-analysis was performed using the random effects model to calculate the standardized mean difference (SMD).
The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials
Critical reviews in food science and nutrition (2019) · Meta analysis · n=606
Thirteen RCTs with 606 participants were included in the meta-analyses.
Effect of Caffeine and Nitrates Combination on Exercise Performance, Heart Rate and Oxygen Uptake: A Systematic Review and Meta-Analysis
Nutrients (2024) · Meta analysis · n=95
The meta-analysis revealed that caffeine and nitrates supplementation (CAF+nitrates) did not enhance performance in time trials (TTs) over the CAF alone (g = -0.06; 95% CI = -0.46 to 0.35; p = 0.78) or nitrates alone (g = 0.29; 95% CI = -0.12 to 0.70; p = 0.17).
Based on meta-analysis showing significant HAM-A score reduction (p=0.0007) and RCT evidence at 125mg dose. High heterogeneity (I2=98%) in pooled analysis suggests variable response. Extract standardization affects bioavailability.
Based on multiple meta-analyses showing 3-6mg/kg optimal dosing. Performance benefits plateau around 200-300mg with increased jitteriness at higher doses.
AI-estimated from published studies. Interpret as directional guidance.
Both Ashwagandha and Caffeine are closely matched — the best choice depends on your specific health goals.
For boost daily energy, Caffeine has a higher relevance score (98 vs 60).
No known interactions between Ashwagandha and Caffeine have been documented in our database. However, always consult a healthcare provider before combining supplements.