Iron supplementation improves fatigue in iron-deficient but non-anemic women.

No correction for multiple tests: The study tested 15+ outcomes simultaneously but never adjusted p-values — the main fatigue result (p = 0.02) disappears when applying standard statistical corrections, meaning it could be a false positive

Large placebo effect: The placebo group improved by 28.8% on their own — iron only added ~19% on top of that, and this difference is statistically fragile without proper statistical correction.

Conflict of interest: The study was funded by the company that makes the iron supplement tested, and several authors have financial ties to iron supplement manufacturers

Bottom line: While this study points in a promising direction, the statistics are not strong enough to confidently conclude that iron supplementation reliably improves fatigue in non-anemic iron-deficient women.