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Head-to-head evidence comparison — which supplement is right for you?
Iron wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
11 of 15 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
5 of 6 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Iron and Manganese have evidence — compare verdict strength side-by-side.
18-45mg elemental iron for deficiency (varies by severity)
On empty stomach if tolerated, Away from tea, coffee, dairy
Ferrous bisglycinate (gentle, well-absorbed) or iron protein succinylate
2-5mg daily
With food, Can take with other minerals
Manganese Bisglycinate or Citrate
Iron reduces manganese absorption; manganese may slightly reduce iron
Separate doses by 1-2 hours if taking therapeutic amounts
2-4 weeks
4-8 weeks
4-12 weeks
12-24 weeks
4-8 weeks
With chronic excess
Daily oral iron supplementation during pregnancy
The Cochrane database of systematic reviews (2024) · Meta analysis · n=48971
There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence).
The Prevalence of Anemia among Pregnant Women in China: A Systematic Review and Meta-Analysis
Nutrients (2024) · Meta analysis · n=722
The results showed that the prevalence of anemia, ID, and IDA among pregnant women in China were 30.7% (95% CI: 26.6%, 34.7%), 45.6% (95% CI: 37.0%, 54.2%), and 17.3% (95% CI: 13.9%, 20.7%), respectively.
Treatment for women with postpartum iron deficiency anaemia
The Cochrane database of systematic reviews (2024) · Meta analysis · n=572
Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence).
Association of Blood Manganese and Preeclampsia: A Systematic Review and Meta-analysis
Biological trace element research (2024) · Meta analysis · n=1113
Pooled results showed that compared to normotensive control, women with PE had significantly lower blood Mn concentration (standardized mean difference: -0.36, 95% confidence interval: -0.50 to -0.22, p < 0.001; I2 = 67%).
Manganese Exposure and Metabolic Syndrome: A Systematic Review and Meta-Analysis
Nutrients (2022) · Meta analysis
Therefore, the present review examined the association between dietary and environmental Mn exposure, and MetS risk.
Serum trace elements and osteoarthritis: A meta-analysis and Mendelian randomization study
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS) (2024) · Meta analysis
The study suggests that there is an association between the occurrence of OA and variations in serum levels of copper, manganese, cadmium, and selenium.
Based on meta-analyses showing hemoglobin improvements of 2.01-5.30 g/dL in iron deficient populations. Higher doses show diminishing returns with increased GI side effects. Effectiveness varies significantly by baseline iron status and form used.
Multiple meta-analyses demonstrate dose-dependent neurotoxicity risk. Studies consistently show neurological impairment with excess manganese exposure. Risk estimates are conservative based on childhood neurodevelopment meta-analysis showing IQ decrements with elevated exposure.
AI-estimated from published studies. Interpret as directional guidance.
Iron has a higher evidence score (9/10 vs 4/10) and wins in 2 of 3 categories.
For boost daily energy, Iron has a higher relevance score (90 vs 25).
Iron reduces manganese absorption; manganese may slightly reduce iron Separate doses by 1-2 hours if taking therapeutic amounts Consult a healthcare provider for personalized advice.