Ingredient face-off
Best Iron Supplements Compared: Bisglycinate vs Ferrous Sulfate vs Polysaccharide Iron
Iron supplementation is one of the most-searched supplement categories and one of the most-abused — most adults with fatigue reach for iron before checking their ferritin, and over-supplementation causes real harm (iron overload, GI damage, increased infection risk). Form matters: bisglycinate is dramatically better tolerated than ferrous sulfate at similar elemental doses. Liquid formats aid absorption for iron-deficient individuals. This ranks the top-scoring iron products in our catalog on Evidence, Formulation (elemental iron + form), Manufacturing, Safety (contraindications + interaction warnings), Transparency, and Sustainability. Read the rubric →
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Which iron form should you take?
Always confirm iron deficiency with a blood test first — serum ferritin + iron panel + CBC. Iron supplementation without confirmed deficiency risks iron overload (hereditary hemochromatosis affects ~1 in 200 people of European descent and often goes undiagnosed). Once deficiency is confirmed, form + dose choice matters:
| Your situation | Best form | Elemental target | Why |
|---|---|---|---|
| Iron-deficiency anemia (adult) | Bisglycinate or polysaccharide iron | 27-45 mg elemental/day | Better GI tolerance than ferrous sulfate at similar absorption; less constipation and nausea |
| Pregnancy / preconception | Ferrous bisglycinate | 27 mg elemental/day (RDA) | Standard prenatal iron; bisglycinate reduces the common pregnancy-nausea + constipation issues from ferrous sulfate |
| Vegan / plant-based diet | Bisglycinate + vitamin C | 18-27 mg elemental/day | Non-heme iron absorbs 2-4× better with vitamin C; MegaFood Blood Builder pairs both |
| Pediatric (medically indicated) | Liquid polysaccharide iron (pediatrician-monitored) | Weight-based, physician-directed | Iron overdose is a leading cause of pediatric poisoning — must be pediatrician-monitored + child-resistant packaging |
| Older adults with fatigue | DON'T supplement without workup | — | Ferritin should be checked; older-adult fatigue often has non-iron causes (B12, thyroid, sleep). Supplementing empirically risks masking a different problem |
The safety point most iron labels under-state: confirm your ferritin first. Iron overload (hemochromatosis, secondary iron overload from over-supplementation) causes liver damage, joint pain, and increased cardiovascular risk. If your ferritin is above 200 ng/mL (women) or 300 ng/mL (men), you should NOT be supplementing iron regardless of what a supplement label says. Read our full iron-supplementation deep-dive.
Head-to-head summary
| # | Product | Score | Tier | Strongest on |
|---|---|---|---|---|
| 1 | MegaFood Blood Builder Vegan Iron Supplement 60ct - New — MegaFood | 86 | Elite | Formulation + Evidence |
| 2 | Solgar Gentle Iron 25 mg 180 Vegetable Capsules — Solgar | 82 | Verified | Formulation + Manufacturing |
| 3 | Albion Ferrochel Iron | 74 | Verified | Formulation + Evidence |
| 4 | Albion Multi-Mineral With Iron | 72 | Verified | Formulation + Transparency |
| 5 | Albion Multi-Mineral without Iron | 72 | Verified | Formulation + Safety |
| 6 | NovaFerrum Pediatric Drops, Liquid Iron Supplement Raspberry Grape | 70 | Verified | Evidence + Formulation |
| 7 | SunActive Iron - Non-Irritating | 70 | Verified | Formulation + Safety |
| 8 | NovaFerrum 125 High Potency Liquid Iron Supplement For Adults, 6 Fl Oz | 68 | Standard | Formulation + Evidence |
Top score: MegaFood Blood Builder Vegan Iron Supplement 60ct - New at 86/100 — see the deep-dive for the reasoning.
Per-product deep dive
#1 MegaFood Blood Builder Vegan Iron Supplement 60ct - New86/100 · Elite
[Rescored via evidence crawl] Previous score undefined → new 86. Evidence found: D'Adamo CR, Novick JS, Feinberg TM, Dawson VJ, Miller LE. A food-derived dietary supplement containing a low dose of iron improved markers of iron status among nonanemic iron-deficient women. J Am Coll Nutr. 2018;37(4):342-349. DOI:10.1080/07315724.2018.1427158. PMID:29533710. | Milman N, et al. J Perinat Med. 2014;42(2):197-206. | MegaFood B Corp Certification, glyphosate residue-free certification, Non-GMO Project Verified.. Rationale: The vegan version delivers the exact same 26 mg iron + vitamin C + folate + B12 formula that was tested in D'Adamo 2018 - the only difference is the capsule shell material. So the TIER-A brand-anchor RCT applies. Combined with third-party sustainability certifications and the fact that the vegan constituency is often the population most at risk for iron deficiency, this SKU deserves Elite recognition. +10 uplift to 86 Elite. Held below 90 for the same reasons as the flagship: absence of NSF/USP facility certification layered on top of the trial, and iron supplementation still requires prior blood-work confirmation as a safety gate.
See the full MegaFood Blood Builder Vegan Iron Supplement 60ct - New page →
#2 Solgar Gentle Iron 25 mg 180 Vegetable Capsules82/100 · Verified
[Rescored via evidence crawl] Previous score 72 → new 82. Evidence found: Milman N, et al. Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy. J Perinat Med. 2014;42(2):197-206. | Ferrari P, et al. Treatment of mild non-chemotherapy-induced iron deficiency anemia: oral ferrous bisglycinate chelate vs IV iron sucrose. Biomed Pharmacother. 2012;66(6):414-8. | Albion Minerals patents and PK dossiers documenting bisglycinate chelate absorption and reduced GI side effects vs sulfate.. Rationale: Solgar Gentle Iron is Albion iron bisglycinate chelate (Ferrochel). Milman 2014 head-to-head RCT showed 25 mg bisglycinate matches 50 mg ferrous sulfate for anemia prevention in pregnancy, with significantly better GI tolerance. TIER-B evidence for the specific form. +10 uplift is honest given both efficacy parity at lower dose AND meaningfully reduced constipation/nausea profile.
See the full Solgar Gentle Iron 25 mg 180 Vegetable Capsules page →
#3 Albion Ferrochel Iron74/100 · Verified
Ferrochel is Albion's patented iron bisglycinate with the strongest evidence base for iron repletion tolerability — non-inferior efficacy to ferrous sulfate with far fewer GI side effects (Milman 2014; Coplin 1991). Named-source branded raw material lifts this to solid Verified. Alt-day dosing (Stoffel 2017) improves fractional absorption. Would move to Elite with dosing-guidance disclosure and third-party verification.
#4 Albion Multi-Mineral With Iron72/100 · Verified
Albion chelated multi-mineral including iron bisglycinate (Ferrochel) — appropriate for menstruating women and iron-deficient users. All-chelate TRAACS forms are best-absorbed. Verified tier. Adult men and post-menopausal women should generally choose the iron-free variant (Zacharski 2007). Would move higher with elemental disclosure per mineral and NSF verification.
#5 Albion Multi-Mineral without Iron72/100 · Verified
Iron-free Albion chelated multi-mineral is appropriate for adult men and post-menopausal women (avoiding iron overload — Zacharski 2007). All-chelate TRAACS forms are best-absorbed with less GI upset than oxide-based multi-minerals. Verified tier. Would move higher with disclosed elemental doses per mineral and NSF verification.
#6 NovaFerrum Pediatric Drops, Liquid Iron Supplement Raspberry Grape70/100 · Verified
NovaFerrum Pediatric Drops — polysaccharide iron complex in pediatric-dose liquid drops with kid-appropriate raspberry/grape flavoring. Iron supplementation in pediatric iron-deficiency anemia is one of the most-studied nutritional interventions; NovaFerrum is a legitimate pediatric-iron brand recommended by pediatric practitioners. Held below Elite by (1) pediatric iron dosing MUST be prescribed/monitored by pediatrician — parent self-supplementation without guidance is a real risk; (2) sold via pharmacy reseller; (3) iron overdose in children is a leading cause of pediatric poisoning — child-resistant packaging + prominent poison-control warnings should be verified. Would move to Elite 85+ with pediatrician-monitoring warning language + poison-control number prominently displayed.
See the full NovaFerrum Pediatric Drops, Liquid Iron Supplement Raspberry Grape page →
#7 SunActive Iron - Non-Irritating70/100 · Verified
SunActive Fe is a branded microencapsulated ferric pyrophosphate iron with published tolerability data — reduced GI irritation compared to ferrous sulfate/fumarate (Fidler 2004) makes it a good option for iron-deficiency-prone individuals who cannot tolerate standard iron. Named branded raw material lifts this to low Verified. Would move higher with disclosed elemental iron, alt-day dosing guidance (Stoffel 2017), and third-party assay.
#8 NovaFerrum 125 High Potency Liquid Iron Supplement For Adults, 6 Fl Oz68/100 · Standard
NovaFerrum liquid iron — polysaccharide-iron complex form. Iron polysaccharide has better GI tolerance than ferrous sulfate at comparable elemental iron doses (Powers 2017). Liquid delivery aids adherence and allows flexible dosing. 125 mg elemental iron per dose is at the upper end of therapeutic range for adult iron-deficiency treatment. Held below Verified by (1) iron supplementation without prior serum ferritin/iron panel workup is a safety concern — the label warning language could be stronger; (2) sold via pharmacy reseller; (3) 125mg is above what's needed for repletion in most cases and could cause over-supplementation risk. Would move to Verified 70+ with prominent 'confirm iron deficiency via lab test first' warning + lower-dose SKU option.
See the full NovaFerrum 125 High Potency Liquid Iron Supplement For Adults, 6 Fl Oz page →
How the scoring works
Every product is scored on six dimensions — evidence (RCT quality supporting the active ingredients at the label dose), formulation (dose adequacy, bioavailability form, redundancy), manufacturing (third-party testing, GMP, facility audits), safety (adverse-event profile, interactions, dose ceiling), transparency (dose disclosure vs proprietary blends, honest marketing), and sustainability (sourcing, packaging, corporate practice). Tier thresholds: Elite 85+, Verified 70–84, Standard 50–69, Rejected 0–49. Rejected products stay listed with reasons. Full rubric →