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A-F grade per outcome, combining overall evidence with goal-specific relevance. A = strong evidence; F = insufficient. Hover a badge for details.
Direct side-by-side from the meta-analysis. Each row is an outcome where ≥2 of your selected supplements have pooled data. Best effect per row highlighted.
| Outcome | Caffeine | Iron |
|---|---|---|
| Improve endurance — Vo2max + better · mL/kg/min | +0.9best preliminary | +3.4 weak · CI ∋ 0 |
200mg
Morning · with food (preferred)
Pill/capsule for precise dosing
30mg elemental iron
Between meals
Ferrous bisglycinate (gentle, well-absorbed) or iron protein succinylate
15-45 minutes
30-60 minutes
30-60 minutes
2-4 weeks
4-8 weeks
4-12 weeks
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