Iron deficiency anemia
Supplements studied for iron deficiency anemia.
Overview
Iron deficiency anemia has strong evidence for its namesake supplement. Iron (WA 88; high effect size, very high evidence, very high trust; 25 studies) effectively treats and prevents anemia across ages, raising hemoglobin over weeks though full iron repletion may take months. Alternate-day dosing may improve absorption and tolerability versus daily use.
Vitamin A (WA 52; low effect size, high evidence, medium trust; 4 studies) and Taurine (WA 44; low effect size, low evidence, medium trust; 1 study) have uncertain or adjunctive roles—vitamin A may help iron markers in some groups but not when added to iron and folate in pregnancy; taurine plus iron improved hemoglobin in one small women's trial.
See the heatmap and evidence reviews below.
Effect graph
Relevant supplements
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Studies
Find individual evidence reviews for supplements sorted by DEX Score.
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IronView supplement →
Proven purchase·★★★★★
How we scored this▸
- Iron supplements, especially in the form of ferrous sulfate, are effective for treating and preventing iron deficiency anemia in people of all ages.
- They work by increasing the amount of hemoglobin in the blood over a few weeks, but it can take several months to fully restore iron stores.
- Other forms of iron supplements are also available and work well.
- Taking iron every other day or a few times a week may help the body absorb iron better and cause fewer stomach problems compared to daily dosing.
- However, daily or twice-daily iron may be needed for people with more severe anemia to improve blood levels faster.
- Children also respond well to both approaches, with frequent dosing providing more benefit.
- If iron supplements taken by mouth cause side effects or do not work, doctors may use iron given through an infusion.
- This method can help raise iron and blood levels more quickly and reduce the need for blood transfusions during surgery.
- Transfusions are usually only needed in severe cases with symptoms.
- It is important to keep taking iron supplements even after anemia improves to fully restore iron stores and consult healthcare providers about the best dosing and treatment length.
- Taking iron supplements might also reduce tiredness in people who have low iron but no anemia, though more evidence is needed.
Browse 25 studies·9 meta-analyses
AGA Clinical Practice Update on Management of Iron Deficiency Anemia: Expert Review2024
AGA clinical practice guidance recommends oral ferrous sulfate once daily with vitamin C when tolerated, and IV iron when oral iron fails, is not absorbed, or faster repletion is needed.
- Population
- Adults
MetaEfficacy of daily versus intermittent oral iron supplementation for prevention of anaemia among pregnant women: a systematic review and meta-analysis2024n=4,365
A meta-analysis of 26 RCTs (4,365 pregnant women) found intermittent oral iron (~120 mg/day) raised hemoglobin similarly to daily 60 mg iron but caused less nausea, diarrhea, and constipation.
- Dose
- 120 mg/day
- Population
- Women
- Participants
- 4,365
MetaOral iron supplementation and anaemia in children according to schedule, duration, dose and cosupplementation: a systematic review and meta-analysis of 129 randomised trials2023n=34,564
A meta-analysis of 129 pediatric iron trials (34,564 children) found frequent and intermittent regimens similarly reduced anemia; moderate-to-high doses improved hemoglobin and ferritin more than low doses.
- Effect
- Benefit
- Duration
- 1–3 months
- Population
- Children/adolescents
- Participants
- 34,564
- Ages
- <20
MetaRole of iron in the reduction of anemia among women of reproductive age in low-middle income countries: insights from systematic review and meta-analysis2023
A meta-analysis of RCTs in low- and middle-income countries found iron therapy improved hemoglobin and ferritin in women of reproductive age, though heterogeneity across studies was high.
- Effect
- Benefit
- Population
- Women
MetaTreatment efficacy of vitamin C or ascorbate given as co-intervention with iron for anemia - A systematic review and meta-analysis of experimental studies2023n=905
A meta-analysis of 7 RCTs (905 anemic participants) found adding vitamin C or using ferrous ascorbate with oral iron did not significantly improve hemoglobin or ferritin versus iron alone.
- Effect
- No Benefit
- Population
- Patients with anemia
- Participants
- 905
British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults2021
British Society of Gastroenterology guidelines recommend investigating underlying causes of iron deficiency anemia and using oral or IV iron replacement tailored to tolerance, absorption, and comorbid conditions.
- Population
- Postmenopausal women
Comparing oral iron bisglycinate chelate, lactoferrin, lactoferrin with iron and iron polymaltose complex in the treatment of children with iron deficiency anemia2021n=120
In 120 children with iron-deficiency anemia, iron bisglycinate, iron polymaltose, and lactoferrin with iron improved iron stores more than lactoferrin alone, with more side effects in bisglycinate groups.
- Effect
- Benefit
- Dose
- 100 mg/day
- Population
- Children/adolescents
- Participants
- 120
Clinical trialEffectiveness of iron polymaltose complex in treatment and prevention of iron deficiency anemia in children: a systematic review and meta-analysis2021n=274
A meta-analysis of 8 pediatric RCTs (493 children) found ferrous sulfate was more effective than iron polymaltose complex for raising hemoglobin and ferritin in iron-deficiency anemia treatment.
- Effect
- Benefit
- Population
- Children/adolescents
- Participants
- 274
MetaIron preparations for women of reproductive age with iron deficiency anaemia in pregnancy (FRIDA): a systematic review and network meta-analysis2021n=9,145
A network meta-analysis of 53 pregnancy trials (9,145 women) found IV iron sucrose and ferric carboxymaltose improved hemoglobin and ferritin more than oral ferrous sulfate for iron-deficiency anemia.
- Effect
- Benefit
- Dose
- 60 mg/day
- Population
- Women
- Participants
- 9,145
Systematic reviewComparison of different doses of daily iron supplementation for anemia prophylaxis in pregnancy: A systematic review2020
A systematic review of 11 pregnancy iron prophylaxis trials found 30 mg/day maintained hemoglobin in global studies, while Indian data showed inconsistent results between 60 and 120 mg/day doses.
- Dose
- 30 mg/day
- Population
- Women
CrossoverIron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women2020n=19
In 19 anemic women, alternate-day 200 mg ferrous sulfate produced roughly twice the fractional iron absorption of 100 mg given on consecutive days, likely due to lower hepcidin on non-consecutive dosing.
- Dose
- 200 mg/day
- Population
- Women
- Participants
- 19
Psychiatric disorders risk in patients with iron deficiency anemia and association with iron supplementation medications: a nationwide database analysis2020
In Taiwanese adults with newly diagnosed iron-deficiency anemia, IDA was associated with 52% higher psychiatric disorder risk; iron supplementation in IDA patients lowered psychiatric and sleep disorder risk.
- Effect
- Benefit
- Population
- Adults
- Ages
- 20+
RCTRandomized controlled trial of twice-daily versus alternate-day oral iron therapy in the treatment of iron-deficiency anemia2020n=62
In 62 women with iron-deficiency anemia, twice-daily 60 mg iron raised hemoglobin ≥2 g/dL in more patients at 3 and 6 weeks than alternate-day 120 mg, though alternate-day dosing caused less nausea.
- Effect
- Benefit
- Duration
- 6 weeks
- Dose
- 60 mg 2×/day
- Population
- Women
- Participants
- 62
Open-labelThe Efficacy and Safety of Vitamin C for Iron Supplementation in Adult Patients With Iron Deficiency Anemia: A Randomized Clinical Trial2020n=426
In 440 adults with iron-deficiency anemia, oral iron alone was equivalent to iron plus vitamin C for hemoglobin recovery at 2 weeks (mean rise 1.84 vs 2.00 g/dL), suggesting vitamin C co-supplementation is not essential.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 100 mg/day
- Population
- Women
- Participants
- 426
- Avg age
- ~38
MetaIntermittent iron supplementation for reducing anaemia and its associated impairments in adolescent and adult menstruating women2019n=10,996
A Cochrane meta-analysis of 25 RCTs (10,996 menstruating women) found intermittent oral iron reduced anemia risk (RR 0.65) and improved hemoglobin (+5.2 g/L) and ferritin versus placebo or no treatment.
- Effect
- Benefit
- Dose
- 60 mg/day
- Population
- Women
- Participants
- 10,996
RCTIron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials2017n=10
In iron-depleted women, alternate-day iron dosing increased fractional absorption versus consecutive daily dosing; single morning doses matched split doses for absorption with lower hepcidin elevation.
- Duration
- 28 days
- Dose
- 60 mg/day
- Population
- Women
- Participants
- 10
- Ages
- 18–40
MetaDaily iron supplementation for improving anaemia, iron status and health in menstruating women2016n=8,506
A Cochrane review of 67 RCTs (8,506 menstruating women) found daily iron reduced anemia risk (RR 0.39) and raised hemoglobin (+5.3 g/L) versus control, with more gastrointestinal side effects.
- Effect
- Benefit
- Dose
- 5.3 g/day
- Population
- Women
- Participants
- 8,506
- Ages
- 12–50
Systematic reviewBenefits of iron supplementation for low birth weight infants: a systematic review2012
A systematic review of 15 trials in low birth weight or premature infants found iron supplementation improved hematologic iron markers and reduced iron-deficiency anemia prevalence, with insufficient evidence on growth or neurodevelopment.
- Effect
- Benefit
- Duration
- 1 week–18 months
- Population
- Children/adolescents
Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age)2010
AAP clinical guidance recommends screening and preventing iron deficiency and iron-deficiency anemia in infants and toddlers 0–3 years because deficiency may impair neurodevelopment even without anemia.
- Population
- Children/adolescents
- Ages
- 0–3
MetaEffect of sodium iron ethylenediaminetetra-acetate (NaFeEDTA) on haemoglobin and serum ferritin in iron-deficient populations: a systematic review and meta-analysis of randomised and quasi-randomised controlled trials2008
A meta-analysis of 7 trials found sodium iron EDTA (NaFeEDTA) significantly raised hemoglobin (+8.6 g/L) and serum ferritin in iron-deficient populations with good tolerability.
- Effect
- Benefit
- Dose
- 8.6 g/day
Systematic reviewEffect of iron supplementation on haemoglobin response in children: systematic review of randomised controlled trials2007
A systematic review of 55 pediatric iron RCTs found supplementation raised hemoglobin by 0.74 g/dL on average, with greater benefit in anemic children and smaller effects in malaria hyperendemic areas.
- Effect
- Benefit
- Dose
- 0.74 g/day
- Population
- Children/adolescents
GuideIron deficiency anemia2007
A clinical review notes iron-deficiency anemia affects up to 20% of reproductive-age women; serum ferritin is preferred for diagnosis and a 1–2 g/dL hemoglobin rise after 1 month of oral iron supports treatment response.
- Dose
- 1–2 g/day
- Population
- Pregnant women
- Ages
- 65+
MetaIron(III)-hydroxide polymaltose complex in iron deficiency anemia / review and meta-analysis2007n=557
A meta-analysis of 6 adult trials (557 patients) found iron polymaltose complex achieved similar hemoglobin gains as ferrous sulfate for iron-deficiency anemia but with fewer gastrointestinal adverse events.
- Effect
- Benefit
- Duration
- 2 months
- Population
- Adults
- Participants
- 557
MetaIron supplementation in early childhood: health benefits and risks2006
A review of 26 RCTs in young children found iron supplementation improved hematologic status and may aid development in deficient or anemic children, but benefits and risks vary by iron status and malaria endemicity.
- Effect
- Benefit
- Population
- Children/adolescents
- Ages
- 0–59
RCTProphylactic iron supplementation after Roux-en-Y gastric bypass: a prospective, double-blind, randomized study1998n=29
In 56 women after Roux-en-Y gastric bypass, prophylactic oral iron 320 mg twice daily for up to 2 years prevented iron deficiency but did not consistently prevent anemia versus placebo.
- Effect
- Benefit
- Duration
- 2 years
- Dose
- 320 mg 2×/day
- Population
- Women
- Participants
- 29
Vitamin AView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It’s uncertain if taking vitamin A helps prevent or treat iron deficiency anemia.
- Some studies found that vitamin A improves blood iron levels and lowers anemia risk in children and pregnant women without anemia.
- But for pregnant women already taking iron and folate, adding vitamin A didn’t help blood iron levels.
- In preterm babies with anemia, taking vitamin A plus vitamin B helped, but vitamin A alone did not improve anemia.
Browse 4 studies·1 meta-analysis
Controlled trialClinical study of vitamin A combined with vitamin B in prevention and treatment of anemia in premature infants2019
A study in children/adolescents found that the ratio of blood transfusion in group C was lower than that in group A and B (P 0.05).
- Effect
- Benefit
- Population
- Children/adolescents
MetaVitamin A and carotenoids during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis2012
A meta-analysis found that among HIV-positive women, supplementation was protective against low birthweight (<2.5 kg) [risk ratio (RR) = 0.79 [95% confidence interval (CI) 0.64, 0.99]], but no significant effects on preterm delivery or small-for-gestational age were observed.
- Effect
- Benefit
- Population
- Women
RCTImpact of vitamin A supplementation on anaemia and plasma erythropoietin concentrations in pregnant women: a controlled clinical trial2001
A randomized trial in women found that 30 mg there were no significant differences between vitamin A and control groups in the slope of the regression line between log10 erythropoietin and haemoglobin at enrollment or 38 wk, and between enrollment and follow-up within either group.
- Effect
- No Benefit
- Dose
- 30 mg
- Population
- Women
Systematic reviewThe role of vitamins in the prevention and control of anaemia2000
A systematic review found that vitamin B6 effectively treats sideroblastic anaemia.
- Population
- Infants
TaurineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is unclear if taurine helps treat iron deficiency anemia.
- One small study in women found that taking taurine together with iron supplements improved blood hemoglobin, red blood cells, and iron stores better than iron alone.
- More research is needed to confirm these benefits.
Browse 1 study
RCTPossible ameliorative effect of taurine in the treatment of iron-deficiency anaemia in female university students of Gaza, Palestine2002n=730
In women with iron-deficiency anemia, adding taurine to iron sulfate improved hemoglobin recovery versus iron alone in this clinical study.
- Effect
- Benefit
- Duration
- 20 weeks
- Dose
- 1000 mg/day
- Population
- Women
- Participants
- 730
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.