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Head-to-head evidence comparison — which supplement is right for you?
Iron wins 3 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
Mostly mechanism / observational
Top outcomes
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
Prescription-only, clinician-titrated. Subcutaneous (Wegovy weight management: escalate to 2.4 mg once weekly; Ozempic diabetes: 0.5-2.0 mg once weekly). Oral (Rybelsus diabetes: 3-14 mg once daily). DO NOT self-dose.
any
Subcutaneous once-weekly injection (Ozempic / Wegovy)
2-4 weeks
4-8 weeks
4-12 weeks
Weeks to months
Months (titrated over 16-20 weeks)
Months to years
Especially during dose escalation
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).
Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1).
N Engl J Med (2021) · Rct · n=1961
Double-blind RCT in 1,961 adults with obesity/overweight WITHOUT diabetes, randomized 2:1 to subcutaneous semaglutide 2.4 mg/week or placebo plus lifestyle for 68 weeks
Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT).
N Engl J Med (2023) · Rct · n=17604
Large cardiovascular-outcomes RCT: 17,604 patients with preexisting cardiovascular disease and overweight/obesity but WITHOUT diabetes
Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6).
N Engl J Med (2016) · Rct · n=3297
Pre-approval cardiovascular-safety RCT in 3,297 patients with type 2 diabetes at high cardiovascular risk, semaglutide (0.5/1.0 mg/week) vs placebo for 104 weeks
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.
AI-estimated from published studies. Interpret as directional guidance.
Iron has a higher evidence score (9/10 vs 8.5/10) and wins in 3 of 3 categories.
No known interactions between Iron and Semaglutide have been documented in our database. However, always consult a healthcare provider before combining supplements.