Home Ingredients Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)
Women's Health

Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)

Evidence Level
Limited
8 Clinical Trials
5 Documented Benefits
2/5 Evidence Score

Iron polymaltose complex is a ferric iron form in which a core of iron(III) hydroxide is wrapped in polymaltose, a chain of glucose units, giving a large, stable molecule that is about 27% iron. It is sold as tablets labeled 100 mg of iron and as syrups and drops, under brands such as Maltofer® and Ferrum Hausmann, and is meant to be taken with meals. In randomized trials in pregnant women with low iron it raised hemoglobin about as much as ferrous sulfate or ferrous ascorbate, and pooled adult trials found similar hemoglobin to ferrous sulfate with fewer stomach complaints. Refilling iron stores was slower in adult trials and in women, though one pregnancy trial found higher ferritin, and in children it raised hemoglobin less than ferrous sulfate. In a placebo-controlled trial in schoolchildren it did not raise hemoglobin. Take iron only if a blood test shows you need it.

Studied Dose 100 to 200 mg elemental iron a day for 8 to 13 weeks in adult and pregnancy trials, and 5 to 6 mg/kg a day in children. These doses exceed the 45 mg/day US adult upper limit and are for low iron confirmed by a blood test.
Active Compound Iron(III)-hydroxide polymaltose complex (iron polymaltose, CAS 53858-86-9): a polynuclear iron(III)-hydroxide core stabilized by a polymaltose shell, molecular weight about 55 kD and about 27% iron by mass. Products are labeled by elemental iron: tablets give 100 mg iron (a 357 mg tablet in one trial) and a syrup 50 mg per 5 mL.

Benefits

Hemoglobin in pregnant women with low iron, compared with iron salts

In an 80-woman trial at 100 mg twice a day for 90 days, hemoglobin rose 2.16 g/dL vs 1.93 g/dL on ferrous sulfate, with no significant difference, and ferritin ended higher (179 vs 157 ng/mL). In a 150-woman trial at 100 mg a day, day 90 hemoglobin and ferritin did not differ from ferrous sulfate or ferrous ascorbate. The maker's data sheet calls pregnancy studies inconclusive.

Supported by Trial 1, Trial 3

Stomach complaints compared with ferrous sulfate

In pooled adult trials, adverse reactions were reported by 14.9% on this complex vs 34.1% on ferrous sulfate, and in two pregnancy trials by 29% vs 56% and 31% vs 78%. In 57 women with low stores the gap was small (28% vs 33% symptom rate), and a pooled analysis in children found no difference.

Supported by Trial 5, Trial 4

Blood count recovery in adults compared with ferrous sulfate

Across six adult trials, hemoglobin after 8 to 13 weeks was similar to ferrous sulfate at equal doses, though the maker's data sheet reports faster normalization on ferrous sulfate. Refilling stores lagged: ferritin was lower with this complex where reported, and in 57 women with low stores ferritin rose 109% on ferrous sulfate but did not change on this complex over 12 weeks.

Supported by Trial 4, Trial 5

Hemoglobin compared with other forms in children

A pooled analysis of six trials in children found a smaller hemoglobin rise than with ferrous sulfate (0.81 g/dL less), and a 125-child trial found a smaller rise than with ferrous ascorbate (3.33 vs 4.88 g/dL). One 103-child trial found no significant hemoglobin difference and fewer stomach complaints (26.9% vs 50.9%).

Supported by Trial 6, Trial 5

Results against placebo in schoolchildren

In 591 schoolchildren with mild anemia in a malaria area of Indonesia, about 6 mg/kg a day for 8 weeks did not raise hemoglobin or ferritin more than placebo, and malaria parasites appeared more often on iron among children whose stores were already full. Only about a quarter had low stores at entry.

Supported by Trial 8

Mechanism of action

1

Ferric iron held in a large, stable carbohydrate complex

The complex is a polynuclear iron(III)-hydroxide core held by polymaltose, about 55 kD in size. It stays soluble across a broad pH range and releases little free iron. Per its datasheet it diffuses through the gut lining about 40 times less than soluble ferrous salts, and its iron is taken up by an active process.

2

Slow uptake with little free iron in the blood

Serum iron barely rises in the first hours after a dose, so blood iron curves do not reflect how much is used. In 10 healthy men, 100 mg of iron as ferrous sulfate raised non-transferrin-bound iron, a loosely held form, while iron polymaltose did not differ from water.

3

Taken with meals, and absorbed more when stores are low

Unlike ferrous salts, which are usually advised on an empty stomach, this complex is labeled to be taken during or right after a meal; food did not lower its absorption in the maker's studies. As with other iron forms, the share absorbed is higher when iron deficiency is greater and falls as the dose rises.

Clinical trials

1
Iron Polymaltose Complex vs Ferrous Sulfate in Pregnancy: 90-Day Multicenter RCT
PubMed

Exploratory, open-label, randomized, multicenter study of Maltofer® or ferrous sulfate, each 100 mg iron twice daily (200 mg a day) for 90 days; primary end point was the change in hemoglobin to days 60 and 90; indexed as receiving non-government research support, but the sponsor, any company ties and any registry number are not stated in the abstract (Ortiz et al. 2011, J Matern Fetal Neonatal Med)

80 pregnant women with hemoglobin of 10.5 g/dL or less, ferritin of 15 ng/mL or less and small red cells (MCV below 80 fL); lead site in Colombia.

The primary end point did not differ: hemoglobin rose 2.16 g/dL on iron polymaltose vs 1.93 g/dL on ferrous sulfate by day 90 (not significant). Ferritin at day 90 was 179 vs 157 ng/mL (P = 0.014). Adverse events affected 12 of 41 (29.3%) vs 22 of 39 (56.4%), P = 0.015.

2
Iron Polymaltose Complex 100 mg vs Ferrous Sulfate 120 mg in Pregnancy: Double-Blind RCT
PubMed

Randomized, double-blind, parallel-group 8-week trial of iron polymaltose complex (100 mg iron) vs ferrous sulfate (120 mg iron) daily; aims were efficacy, safety, compliance and cost; funding not described in the abstract (Saha et al. 2007, MedGenMed)

100 pregnant women aged 20 to 40 at 14 to 27 weeks in Chandigarh, India, with hemoglobin below 9 g/dL and ferritin below 12 mcg/L.

Hemoglobin, red cell indices, serum iron and ferritin rose significantly within both groups; the abstract gives no between-group hemoglobin figures. Adverse effects were less common on iron polymaltose (15 women, 31%, vs 41 women, 78%; P < .001), pill-count compliance was 91% vs 87% (P < .05), and total cost was comparable.

3
Ferrous Ascorbate 100 mg vs Ferrous Sulfate 120 mg vs Iron Polymaltose in Pregnancy: Open-Label RCT
PubMed

Single-center, randomized, open-label 90-day trial: ferrous ascorbate 100 mg iron with 1.5 mg folic acid once daily, ferrous sulfate 60 mg iron twice daily with 5 mg folic acid, or iron polymaltose 100 mg iron once daily; Emcure Pharmaceuticals gifted the ferrous ascorbate and polymaltose products; authors declared no conflicts (Chavan et al. 2021, Indian J Med Res)

177 pregnant women in New Delhi at 12 to 26 weeks with hemoglobin 7 to 9.9 g/dL and ferritin near 9 mcg/L; 150 analyzed.

Hemoglobin at day 90 was 11.3 g/dL on ferrous ascorbate vs 10.99 g/dL on ferrous sulfate (P < 0.05), with no difference at days 30 and 60 and none vs iron polymaltose. Ferritin rose to 31.8, 28.6 and 30.4 mcg/L, not different between groups. Adverse effects affected 42% vs 62% vs 46%; only epigastric pain differed (9 vs 15 women on ferrous sulfate).

4
Iron Polymaltose Complex vs Ferrous Sulfate in Women with Low Iron Stores: 12-Week RCT
PubMed

Single-blind randomized trial (ACTRN12623000529640) of ferrous sulfate (105 mg iron) with sodium ascorbate vs iron(III)-hydroxide polymaltose complex (100 mg iron) daily for 12 weeks; aims were efficacy (ferritin) and tolerability; supported by Western Australian government health funds (per Europe PMC); authors reported no conflicts (McKay et al. 2026, Clin Nutr)

Women in Australia with serum ferritin below 50 mcg/L in three cohorts (athletes, premenopausal and postmenopausal women); 57 completed.

Ferritin rose 109% on ferrous sulfate (P < 0.001) but did not change on the polymaltose complex (+7%, P = 0.727), a significant supplement by time interaction; results did not differ between cohorts. The symptom rate was lower on the complex (28% vs 33%, P < 0.001). Compliance was 94.9%.

5
Iron Polymaltose Complex vs Ferrous Sulfate in Adults: Meta-Analysis of Six Trials
PubMed

Review and meta-analysis using Cochrane methods of comparative trials at equivalent doses; primary end point was hemoglobin after about 2 months, safety was the share with adverse drug reactions; funding not stated in the abstract, the second author's affiliation is not given, and it appeared in the same journal issue as a review by a Vifor employee (Toblli et al. 2007, Arzneimittelforschung)

Adults with iron-deficiency anemia in six comparative trials (one double-blind): 319 on iron polymaltose and 238 on ferrous sulfate; four pediatric trials were excluded for baseline differences.

Hemoglobin at 8 to 13 weeks was 12.13 vs 11.94 g/dL (weighted mean difference 0.01 g/dL, 95% CI -0.23 to 0.21). Where reported, ferritin was lower with iron polymaltose. Adverse reactions occurred in 14.9% vs 34.1% (P < 0.001), mainly upper digestive complaints, stained teeth and diarrhea.

6
Polymaltose Complex vs Ferrous Sulfate in Children: Meta-Analysis of Eight Trials
PubMed

Systematic review and random-effects meta-analysis of randomized trials comparing the oral polymaltose complex with standard oral salts in children; authors declared no competing interests (Mohd Rosli et al. 2021, PeerJ)

493 randomized children in eight trials of treatment or prevention of low stores; six trials (368 children) compared the complex with ferrous sulfate for treatment.

Hemoglobin rose less on the polymaltose complex than on ferrous sulfate (mean difference -0.81 g/dL, 95% CI -1.08 to -0.53; high certainty), and serum storage levels were lower (mean difference -21.24; 3 trials, moderate certainty). Side effects did not differ (3 trials, 274 children). Comparisons with gluconate and bisglycinate could not be settled.

7
Ferrous Ascorbate vs Polymaltose Complex at 6 mg/kg in Children: 3-Month RCT
PubMed

Randomized controlled trial at a government teaching hospital; both groups received 6 mg/kg elemental iron a day for 3 months; blinding not described in the abstract; authors declared no conflicts (Patil et al. 2019, Indian J Pediatr)

125 children aged 1 to 12 in Aurangabad, India, with clinical signs of anemia from low stores.

Hemoglobin rose more on ferrous ascorbate at 1 month (3.13 vs 2.0 g/dL, P = 0.017) and 3 months (4.88 vs 3.33 g/dL, P = 0.001), with faster early rises in reticulocytes and red cell size. Minor adverse reactions occurred on ferrous ascorbate and none on polymaltose complex.

8
Polymaltose Complex vs Placebo in Schoolchildren with Mild Anemia: 8-Week RCT
PubMed

Placebo-controlled randomized trial (ISRCTN 83091970, registered retrospectively), with participants and laboratory staff blinded, of Maltofer® at about 6 mg/kg elemental iron a day, 6 days a week for 8 weeks; primary outcomes were malaria parasites by microscopy and PCR, with hemoglobin and ferritin secondary; funded by the Nutricia Research Foundation; authors declared no competing interests (Prasetyani et al. 2017, Malar J)

591 schoolchildren aged 5 to 18 on Flores, Indonesia, with mild anemia and no malaria parasites at entry (294 on the complex, 297 on placebo); 26.9% had serum storage levels below 30 mcg/L.

The complex did not raise hemoglobin or serum storage levels more than placebo. Malaria parasites seen by microscopy appeared more often on the complex (hazard ratio 2.2, 95% CI 1.2 to 4.0), an excess confined to children with full stores; PCR positivity at week 16 did not differ (16.6% vs 14.3%).

Side effects and drug interactions

Common Potential side effects

Digestive complaints occur, though less often than on ferrous sulfate in several trials: adverse events affected 29.3% vs 56.4% of pregnant women in one trial, and stomach complaints 26.9% vs 50.9% of children in another. The datasheet lists dark stools as very common and nausea, constipation, diarrhea and abdominal pain as common.
Less common effects listed in the datasheet include vomiting, tooth discoloration, gastritis, itching, rash and headache. Dark stools can mask bleeding in the gut, although a standard test for hidden blood in stool still works.
In a placebo-controlled trial in schoolchildren in a malaria area, malaria parasites appeared more often on this complex among children whose iron stores were already full.
The US Tolerable Upper Intake Level for iron is 45 mg a day for adults (40 to 45 mg for infants, children and teens). High doses (45 mg a day or more) may cause nausea and constipation.
People with hereditary hemochromatosis absorb too much iron and are at risk of overload; do not take iron unless a blood test shows you need it.
Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Keep iron out of reach of children, and if a child swallows iron, call a doctor or poison control center immediately.

Important Drug interactions

Calcium and dairy: calcium may reduce absorption of both heme and nonheme iron; take calcium and iron supplements at different times.
Tetracycline and quinolone antibiotics: iron binds them and lowers their absorption; follow the antibiotic label on spacing.
Levothyroxine: iron reduces its absorption; labels advise not taking levothyroxine within 4 hours of iron.
Levodopa: iron supplements may reduce how much levodopa the body absorbs.
Proton pump inhibitors: by lowering stomach acid they can reduce iron absorption.
Vitamin C: enhances absorption of nonheme iron.
Injectable iron: the datasheet advises not taking this complex alongside injectable iron, since oral iron absorption would be reduced.
Tetracycline with this complex: in three small crossover studies reported in the maker's data sheet, this complex did not significantly lower tetracycline absorption; antibiotic labels still advise spacing iron from these drugs.

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Frequently asked questions about Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)

What is iron polymaltose complex?

It is ferric iron held as a core of iron(III) hydroxide inside a shell of polymaltose, a glucose chain, making a large, stable molecule that is about 27% iron. Tablets are labeled 100 mg of iron and a syrup 50 mg per 5 mL; brands include Maltofer® and Ferrum Hausmann. Compare products by the elemental iron on the label.

Is it gentler on the stomach than ferrous sulfate?

Often, in adult and pregnancy trials: pooled adult trials reported adverse reactions in 14.9% vs 34.1%, and two pregnancy trials found about half the rate. The gap was small in a trial in women with low stores (28% vs 33%), and a pooled analysis in children found no difference. Dark stools are very common.

Does it work as well as ferrous sulfate?

For hemoglobin after 2 to 3 months in adults and pregnant women, trials found similar results at equal doses, though ferrous sulfate raised it faster in the maker's adult data. Refilling iron stores was usually slower, and in a 12-week trial in women ferritin did not rise on this complex. In children it raised hemoglobin less, and in a placebo-controlled trial in schoolchildren it did not raise hemoglobin.

How should it be taken, and who should take it?

Take it during or right after a meal. Labels give 100 to 200 mg of iron a day to correct low iron, above the 45 mg US adult upper limit, so use it under medical care after a blood test shows low iron. Keep iron away from children, and if you have hemochromatosis, do not take iron unless your doctor advises it.

What is Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)?

Iron polymaltose complex is a ferric iron form in which a core of iron(III) hydroxide is wrapped in polymaltose, a chain of glucose units, giving a large, stable molecule that is about 27% iron.

What is Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) used for?

Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) is researched primarily for Women's Health. In an 80-woman trial at 100 mg twice a day for 90 days, hemoglobin rose 2.16 g/dL vs 1.93 g/dL on ferrous sulfate, with no significant difference, and ferritin ended higher (179 vs 157 ng/mL).

What is the recommended dosage of Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)?

The clinically studied dose is 100 to 200 mg elemental iron a day for 8 to 13 weeks in adult and pregnancy trials, and 5 to 6 mg/kg a day in children. These doses exceed the 45 mg/day US adult upper limit and are for low iron confirmed by a blood test. Always follow the product label and check with a healthcare provider for personal advice.

Is Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) safe, and does it have side effects?

Side effects and cautions reported for Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) include: Digestive complaints occur, though less often than on ferrous sulfate in several trials: adverse events affected 29.3% vs 56.4% of pregnant women in one trial, and stomach complaints 26.9% vs 50.9% of children in another. It may also interact with some medications. Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) interact with any medications?

Possible interactions include: Calcium and dairy: calcium may reduce absorption of both heme and nonheme iron; take calcium and iron supplements at different times. Tetracycline and quinolone antibiotics: iron binds them and lowers their absorption; follow the antibiotic label on spacing. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose)?

NutraSmarts rates the evidence for Iron Polymaltose Complex (Iron(III) Hydroxide Polymaltose) as Limited (2 out of 5). It is backed by 8 study summaries and 16 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(16 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Ortiz R, Toblli JE, Romero JD, Monterrosa B, Frer C, Macagno E, Breymann C. Efficacy and safety of oral iron(III) polymaltose complex versus ferrous sulfate in pregnant women with iron-deficiency anemia: a multicenter, randomized, controlled study. J Matern Fetal Neonatal Med. 2011;24(11):1347-52. doi: 10.3109/14767058.2011.599080.PubMedUsed to support: Exploratory, open-label, randomized, multicenter study in 80 pregnant women with iron-deficiency anemia (hemoglobin 10.5 g/dL or less, ferritin 15 ng/mL or less, MCV below 80 fL): iron(III) polymaltose complex (Maltofer) or ferrous sulfate, each 100 mg iron twice daily for 90 days. The primary end point, change in hemoglobin to days 60 and 90, did not differ (2.16 vs 1.93 g/dL by day 90, not significant). Ferritin at day 90 was 179 vs 157 ng/mL (P = 0.014), and adverse events affected 29.3% (12 of 41) vs 56.4% (22 of 39), P = 0.015. PubMed indexes it as receiving non-government research support; the sponsor, any company ties and a registry number are not stated in the abstract.
  2. Saha L, Pandhi P, Gopalan S, Malhotra S, Saha PK. Comparison of efficacy, tolerability, and cost of iron polymaltose complex with ferrous sulphate in the treatment of iron deficiency anemia in pregnant women. MedGenMed. 2007;9(1):1. PMCID: PMC1924983.PubMedUsed to support: Randomized, double-blind, parallel-group trial at a teaching institute in Chandigarh, India, in 100 pregnant women aged 20 to 40 at 14 to 27 weeks with hemoglobin below 9 g/dL and ferritin below 12 mcg/L: iron polymaltose complex (100 mg iron) or ferrous sulfate (120 mg iron) daily for 8 weeks. Hemoglobin, red cell indices, serum iron and ferritin rose significantly within both groups; the abstract gives no between-group hemoglobin comparison. Overall adverse effects were more common on ferrous sulfate (41, 78%, vs 15, 31%; P < .001), compliance was 91% vs 87% (P < .05), and total cost was comparable. Funding is not described in the abstract.
  3. Chavan S, Rana P, Tripathi R, Tekur U. Comparison of efficacy & safety of iron polymaltose complex & ferrous ascorbate with ferrous sulphate in pregnant women with iron-deficiency anaemia. Indian J Med Res. 2021;154(1):78-84. doi: 10.4103/ijmr.IJMR_1753_18.PubMedUsed to support: Single-center, randomized, open-label trial in New Delhi (2014 to 2015) in pregnant women at 12 to 26 weeks with hemoglobin 7 to 9.9 g/dL: ferrous sulfate 60 mg iron twice daily plus 5 mg folic acid, iron polymaltose 100 mg iron with 0.55 mg folic acid, or ferrous ascorbate 100 mg iron with 1.5 mg folic acid (Ferium XT) once daily for 90 days; 177 randomized, 150 analyzed. At day 90 hemoglobin was 11.3 g/dL on ferrous ascorbate vs 10.99 g/dL on ferrous sulfate (P < 0.05), with no difference vs iron polymaltose and no difference at days 30 and 60; ferritin rose from about 8.7 to 31.8 mcg/L, not different between groups. Adverse effects: 42% on ferrous ascorbate vs 62% on ferrous sulfate, a significant difference only for epigastric pain (9 vs 15 women). Emcure Pharmaceuticals gifted the ferrous ascorbate and polymaltose products; the authors declared no conflicts.
  4. McKay AK, Broome S, Tee N, Yim KL, Sim M, Peeling P, Burke LM. Oral ferrous sulphate supplementation has greater efficacy, but lower tolerance than iron (III)-hydroxide polymaltose complexes in exercising women with low iron stores. Clin Nutr. 2026;58:106594. doi: 10.1016/j.clnu.2026.106594.PubMedUsed to support: Single-blind 12-week randomized trial (ACTRN12623000529640) in women with serum ferritin below 50 mcg/L, in athlete, premenopausal and postmenopausal cohorts in Australia: ferrous sulfate (105 mg iron) with sodium ascorbate or iron(III)-hydroxide polymaltose complex (100 mg iron) daily; 57 completed. Ferritin rose 109% on ferrous sulfate (P < 0.001) and did not change on the complex (+7%, P = 0.727), with no differences between cohorts. The symptom rate was lower on the complex (28% vs 33%, P < 0.001). Europe PMC lists Western Australian government health funds as support, and the authors reported no conflicts.
  5. Toblli JE, Brignoli R. Iron(III)-hydroxide polymaltose complex in iron deficiency anemia / review and meta-analysis. Arzneimittelforschung. 2007;57(6A):431-8. doi: 10.1055/s-0031-1296692.PubMedUsed to support: Review and meta-analysis by Cochrane methods of trials comparing iron polymaltose complex with ferrous sulfate at equivalent doses. Of 14 comparative trials, 6 in adults (1 double-blind; 319 on the complex, 238 on ferrous sulfate) were analyzed; 4 pediatric trials were excluded for baseline heterogeneity. Hemoglobin at 8 to 13 weeks was 12.13 vs 11.94 g/dL (weighted mean difference 0.01 g/dL, 95% CI -0.23 to 0.21). Where reported, ferritin was lower with the complex. Adverse drug reactions were reported in 14.9% vs 34.1% (P < 0.001). Funding is not stated in the abstract and the second author's affiliation is not given; the paper appeared in the same journal issue as a review of the complex by a Vifor employee.
  6. Mohd Rosli RR, Norhayati MN, Ismail SB. Effectiveness of iron polymaltose complex in treatment and prevention of iron deficiency anemia in children: a systematic review and meta-analysis. PeerJ. 2021;9:e10527. doi: 10.7717/peerj.10527.PubMedUsed to support: Systematic review and meta-analysis of randomized trials comparing oral iron polymaltose complex with standard oral iron in children: 8 trials, 493 children. Against ferrous sulfate for treatment, the complex raised hemoglobin less (mean difference -0.81 g/dL, 95% CI -1.08 to -0.53; 6 trials, 368 children; high certainty) and ferritin less (mean difference -21.24; 3 trials, 183 children; moderate certainty), with no difference in side effects (3 trials, 274 children; high certainty). Evidence against iron gluconate and bisglycinate was too limited to conclude. The authors declared no competing interests.
  7. Patil P, Geevarghese P, Khaire P, Joshi T, Suryawanshi A, Mundada S, Pawar S, Farookh A. Comparison of Therapeutic Efficacy of Ferrous Ascorbate and Iron Polymaltose Complex in Iron Deficiency Anemia in Children: A Randomized Controlled Trial. Indian J Pediatr. 2019;86(12):1112-1117. doi: 10.1007/s12098-019-03068-2.PubMedUsed to support: Randomized trial at a government hospital in Aurangabad, India, in 125 children aged 1 to 12 with signs of iron-deficiency anemia: ferrous ascorbate or iron polymaltose complex at 6 mg/kg elemental iron a day for 3 months. Hemoglobin rose more with ferrous ascorbate at 1 month (3.13 vs 2.0 g/dL, P = 0.017) and 3 months (4.88 vs 3.33 g/dL, P = 0.001), with larger early rises in MCV and reticulocytes. Minor adverse reactions occurred on ferrous ascorbate and none on iron polymaltose. The authors declared no conflicts; blinding is not described in the abstract.
  8. Prasetyani MA, de Mast Q, Afeworki R, Kaisar MM, Stefanie D, Sartono E, Supali T, van der Ven AJ. Effect of a short course of iron polymaltose on acquisition of malarial parasitaemia in anaemic Indonesian schoolchildren: a randomized trial. Malar J. 2017;16(1):50. doi: 10.1186/s12936-017-1691-5.PubMedUsed to support: Placebo-controlled randomized trial (ISRCTN 83091970, registered retrospectively) on Flores, Indonesia, in 591 schoolchildren aged 5 to 18 with mild anemia and no malaria parasites at entry: iron(III)-hydroxide polymaltose complex (Maltofer, 357 mg tablets with 100 mg iron) at about 6 mg/kg iron a day, 6 days a week for 8 weeks, or placebo; participants and laboratory staff were blinded. The complex failed to raise hemoglobin or ferritin, and microscopic malaria parasites appeared more often in the iron group (hazard ratio 2.2, 95% CI 1.2 to 4.0), confined to iron-replete children; PCR positivity at week 16 did not differ (16.6% vs 14.3%). Only 26.9% had ferritin below 30 mcg/L. Funded by the Nutricia Research Foundation; the authors declared no competing interests.
  9. Yasa B, Agaoglu L, Unuvar E. Efficacy, Tolerability, and Acceptability of Iron Hydroxide Polymaltose Complex versus Ferrous Sulfate: A Randomized Trial in Pediatric Patients with Iron Deficiency Anemia. Int J Pediatr. 2011;2011:524520. doi: 10.1155/2011/524520.PubMedUsed to support: Prospective, open-label, 4-month randomized trial in Istanbul in 103 children older than 6 months with iron-deficiency anemia: iron polymaltose complex once daily or ferrous sulfate twice daily, both 5 mg iron/kg a day. Hemoglobin rose 2.3 vs 3.0 g/dL by month 4, not significantly different between groups. Gastrointestinal adverse events affected 26.9% vs 50.9% (P = 0.012), and acceptability scores favored the complex. The study had no external funding, but the paper was prepared by a medical writer funded by a grant from Vifor Pharma.
  10. Joshi U, Shah T, Shah V, Dave B, Shrimali S, Mehta M, Baisil S, Kini BS. Comparative Effectiveness of Iron Supplementation in Indian Pregnant Women: A Network Meta-Analysis of Randomized Controlled Trials. Indian J Community Med. 2026;51(Suppl 4):S601-S611. doi: 10.4103/ijcm.ijcm_73_26.PubMedUsed to support: Network meta-analysis (PROSPERO CRD42024570537) of 17 randomized trials from India (2,228 pregnant women) comparing oral and injectable iron forms for hemoglobin and ferritin. The abstract lists iron polymaltose complex among oral forms with better hemoglobin improvement than ferrous sulfate, but the full text states that iron polymaltose complex did not show a statistically clear difference from its comparator, and the network was sparse. The authors declared no conflicts.
  11. Geisser P, Burckhardt S. The pharmacokinetics and pharmacodynamics of iron preparations. Pharmaceutics. 2011;3(1):12-33. doi: 10.3390/pharmaceutics3010012.PubMedUsed to support: Review of how oral and intravenous iron preparations are absorbed and used, by authors from Vifor Pharma, the developer of Maltofer. It describes iron(III)-polymaltose as a stable complex of non-ionic polynuclear iron(III)-hydroxide with polymaltose, notes only a negligible rise in serum iron in the first six hours after a dose, and states that serum iron curves are not a valid measure of its bioavailability; absorption of iron(III) preparations is reported to be up to seven times better with food. Company-authored review, not a trial.
  12. Schümann K, Solomons NW, Romero-Abal ME, Orozco M, Weiss G, Marx J. Oral administration of ferrous sulfate, but not of iron polymaltose or sodium iron ethylenediaminetetraacetic acid (NaFeEDTA), results in a substantial increase of non-transferrin-bound iron in healthy iron-adequate men. Food Nutr Bull. 2012;33(2):128-36. doi: 10.1177/156482651203300206.PubMedUsed to support: Randomized-sequence crossover study in 10 healthy Guatemalan men given water or 100 mg iron as ferrous sulfate, NaFeEDTA or iron polymaltose, with blood sampled over 270 minutes. Serum iron and non-transferrin-bound iron rose significantly more after ferrous sulfate than after water or the other two compounds, and non-transferrin-bound iron after iron polymaltose did not differ from water. A short absorption-kinetics study, not a supplementation outcome trial.
  13. Healthcare Logistics (New Zealand sponsor); Medsafe. Maltofer 100 mg tablets and 50 mg/5 mL syrup: New Zealand data sheet. Medsafe, New Zealand Medicines and Medical Devices Safety Authority. 2026;Data sheet, date of revision 8 January 2026, read November 2026..SourceUsed to support: Not PubMed-indexed (official New Zealand medicine data sheet, read 2026). States that tablets contain 100 mg iron and the syrup 50 mg per 5 mL as iron polymaltose, a polynuclear iron(III)-hydroxide core surrounded by polymaltose (about 55 kD; about 27% iron, 36% polymaltose by mass; CAS 53858-86-9), stable and soluble over a broad pH range. Adult and adolescent treatment dose is 100 to 200 mg iron daily, prevention 100 mg, taken during or right after a meal; use under age 12 is not recommended as efficacy is not clearly shown. It reports diffusion through the gut lining about 40 times less than soluble iron(II) salts with active uptake, absorption rising with the degree of deficiency and falling with dose, and no negative effect of food. In reference-controlled adult trials ferrous sulfate replenished iron stores more efficiently and normalized hemoglobin faster, while mean hemoglobin at weeks 9 and 12 was similar; studies in pregnant women were inconclusive. Lists dark stools as very common; nausea, constipation, diarrhea and abdominal pain as common; vomiting, tooth discoloration, gastritis, itching, rash and headache among less common effects; contraindicates use in iron overload; advises against combining with injectable iron because oral iron absorption would be reduced; reports no significant reduction of tetracycline absorption, and no reduction of its iron absorption by tetracycline or aluminium hydroxide, in 3 human crossover studies; and notes a standard hidden-blood stool test is not affected.
  14. NIH Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. National Institutes of Health. 2025;Online fact sheet, updated September 4, 2025..SourceUsed to support: Not PubMed-indexed (official NIH fact sheet; read via a 2026 web archive copy because the live site blocked automated access). States the Tolerable Upper Intake Level for iron is 45 mg for adults and 40 to 45 mg for infants, children and adolescents; that supplemental iron at 45 mg/day or more may cause nausea and constipation; that experts suggest taking calcium and iron supplements at different times; that vitamin C enhances nonheme iron bioavailability; that people with hereditary hemochromatosis are at risk of iron overload; that iron supplements may interact with levodopa and levothyroxine (labels advise against taking levothyroxine within 4 hours of iron) and that proton pump inhibitors can reduce iron absorption; and quotes the required US warning that accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6.
  15. MedlinePlus, National Library of Medicine. Ciprofloxacin: MedlinePlus Drug Information. MedlinePlus. 2026;Online drug information page, last revised August 15, 2026..SourceUsed to support: Not PubMed-indexed (official NIH National Library of Medicine drug information, read 2026). Advises that antacids or multivitamins containing calcium, magnesium hydroxide, aluminum hydroxide, zinc or iron be taken at least 6 hours before or 2 hours after ciprofloxacin.
  16. Chartwell RX, LLC. Doxycycline hyclate tablets, capsules and powder for suspension: prescribing information (DailyMed). DailyMed, National Library of Medicine. 2026;Structured product label, set ID 3e7cf78f-3b48-4614-9fa4-c6d1e0c05a35, published October 19, 2026..SourceUsed to support: Not PubMed-indexed (US drug label, read 2026). States that absorption of tetracyclines is impaired by antacids containing aluminum, calcium or magnesium and by iron-containing preparations.