Scores 30/35 for dosage transparency, 25/25 for a clean formula, 24/25 for label completeness. 5 ingredients disclosed with amounts.
capsule · 100 servings · $0.16/servingBuy on iHerb$16.22
10 Best Iron Supplements (October 2026)
Iron is the supplement most likely to be needed by people who don't take it and taken by people who don't need it. It is also the one mineral where the form on the label changes both absorption and side effects. A good iron product states the elemental amount and the form in plain language.
We ranked every iron product in the NIH label database by label quality.
Our top picks
Scores 35/35 for dosage transparency, 25/25 for a clean formula, 23/25 for label completeness. 2 ingredients disclosed with amounts.
capsule · 120 servings · $0.14/servingBuy on iHerb$17.06
Scores 35/35 for dosage transparency, 25/25 for a clean formula, 23/25 for label completeness. 2 ingredients disclosed with amounts.
capsule · 120 servings · $0.14/servingBuy on iHerb$17.06
Top 10 ranked
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Rankings reflect label quality scores (dosage transparency, cleanliness, ingredient profile) — not clinical efficacy. Read methodology
How we ranked them
Every product is scored 0–100 from its label data in the NIH Dietary Supplement Label Database: dosage transparency (35 points — are amounts stated per ingredient, or hidden in a proprietary blend?), label completeness (25), formulation cleanliness (25 — fillers, dyes, titanium dioxide and other non-active ingredients) and ingredient profile (15). The Top 10 admits only products scoring 60 or higher; among those, products with a verified retail listing are shown first so the list is one you can act on. No brand can pay to be included or moved up.
Forms and dosage
- Ferrous sulfate
- The standard, inexpensive form used in most studies; the most likely to cause constipation and nausea.
- Ferrous bisglycinate (chelated)
- Comparable absorption at lower doses with fewer digestive side effects.
- Ferrous gluconate, fumarate
- Common alternatives with different elemental percentages (12% and 33%).
- Heme iron, liposomal iron
- Specialty forms marketed for tolerability; smaller evidence base.
How much to take
The RDA is 18 mg for women aged 19–50, 8 mg for men and post-menopausal women, and 27 mg in pregnancy. The NIH upper limit is 45 mg per day for adults, above which digestive effects are common. Treatment of diagnosed deficiency uses higher doses under supervision. Always read the elemental iron figure — "ferrous sulfate 325 mg" is 65 mg of iron.
Who it's for
People with diagnosed low ferritin or iron-deficiency anemia, menstruating women with heavy periods, pregnancy, and frequent blood donors.
What to watch out for
Taking iron without a blood test (excess accumulates), labels without the elemental amount, and products with a "proprietary" iron source.
All Iron products (1131)
1
Healthy For LifeMineral Supplement
922QualitestTri-Vit With Fluoride 0.25 mg and Iron Drops
923Everyday HealthNZ-Fe Fort
914Healthy For LifeNatural Mineral Supplement
905Zarbee's Naturals BabyMultivitamin with Iron Supplement Natural Grape Flavor
906Rainbow LightComplete Iron Mini-Tabs
907Advanced Nutrition by ZahlerIron Complex
908FloraFlora Iron
909QualitestMulti-Vit With Fluoride 0.25 mg And Iron Drops
9010Good 'N NaturalEasy Iron Iron Glycinate 28 mg
8811Nature's BountyMulti-Day Multivitamin Plus Iron
8812NutriGoldOrganic Iron Gold 18 mg
8813Basic VitaminsMulti Vitamin with Iron
8814Global Healing CenterIron Fuzion
8815NovaFerrum Pediatric DropsMultivitamin with Iron Raspberry Grape Flavor
8816Superior SourceChildren's Iron 5 mg
8817ProCaps LaboratoriesIron Plus
8818NovaFerrum Pediatric DropsMulti-Vitamin with Iron Raspberry Grape Flavored
8819NovaFerrum Pediatric DropsMultivitamin with Iron Raspberry Grape Flavored
8820Good StateIonic Iron 10,000 PPM
88Frequently Asked Questions
Which iron supplement causes the least stomach upset?
Ferrous bisglycinate is the most consistently tolerated in comparisons with ferrous sulfate, at similar absorption. Taking any form every other day, rather than daily, also reduces side effects without much loss in absorption.
Should I take iron with vitamin C?
Vitamin C increases non-heme iron absorption, which is why many products combine them. It is helpful but not required; a glass of orange juice does the same.
How are iron supplements ranked?
Products are ranked by SupplementScore, which evaluates label quality across four categories: dosage transparency (35 pts), label completeness (25 pts), formulation cleanliness (25 pts), and ingredient profile (15 pts). The score is based on data from the NIH Dietary Supplement Label Database, not marketing claims.
Does a higher score mean the supplement is more effective?
No. The SupplementScore measures label quality — how transparent, clean, and well-documented a product is. It does not measure clinical efficacy, bioavailability, or third-party testing. A higher score means better label practices, not guaranteed results.
How many iron supplements were analyzed?
We analyzed 1,131 iron products from the NIH DSLD database, which contains label data for over 116,000 dietary supplements sold in the United States.
This article is for information only and is not medical advice. Talk to a clinician before starting a supplement, especially if you are pregnant, take medication or have a health condition.