Iron
Of 8,749 on-market iron products in the January 2026 DSLD dump, the median declared dose is 4 elemental mg, and 77.3% list unspecified/undisclosed form as the primary form.
Form share
Of 8,525 products with an identifiable primary form, here is the share held by each form of Iron on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| unspecified/undisclosed form | Unrated | 6,594 | 77.3% |
| Ferrous Fumarate | Unrated | 1,174 | 13.8% |
| Ferrous/Iron Bisglycinate Chelate | Tier 1 | 293 | 3.4% |
| Iron Amino Acid Chelate | Tier 1 | 167 | 2.0% |
| Ferrous Sulfate | Tier 2 | 159 | 1.9% |
| Ferrous Gluconate | Unrated | 138 | 1.6% |
Forms we recognize but found no primary-form products for in this release: Iron (naturally occurring / food-source).
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (elemental mg), among 7,608 products with a disclosed amount, against the RDA of 18 and UL of 45.
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- 74.1% of products fall below the fairy-dust threshold (12 mg, 20% of the studied low dose).
- 0.8% of products don't disclose an amount because Iron is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (elemental mg) to see exactly how it compares to the 7,061 on-market iron products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for iron on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Label discloses only "Iron" with no salt form (largest single bucket, ~9,457 rows).
Elemental fraction: 32.9% (FeC4H2O4, anhydrous (fumarate salts don't commonly form stable hydrates))
Widely marketed as comparably bioavailable to ferrous sulfate with less GI upset; in a randomized isotope study (57Fe fumarate vs 58Fe sulfate) absorption did not differ significantly in non-anemic Mexican women (17.5% vs 20.5%), infants (7.0% vs 7.2%) or young children (6.3% vs 5.9%). Usefulness in iron-deficient subjects was not established, so no tier is assigned.
Source: Harrington M et al. 2011, Eur J Clin Nutr 65(1):20-25, PMID 20842166
If equivalent to ferrous bisglycinate chelate, showed substantially higher apparent bioavailability than ferrous sulfate in a 28-day matched-group trial in 40 infants/young children with iron-deficiency anemia (not stated as randomized).
Source: Pineda O, Ashmead HD. 2001, Nutrition 17(5):381-384, PMID 11377130
Elemental fraction: 20.1% (FeSO4 x 7H2O, heptahydrate (classic commercial/OTC form; a dried monohydrate at 0.329 also exists -- check specific labels))
Reference-standard iron salt used as the comparator in most bioavailability literature; showed lower apparent bioavailability (26.7%) than bisglycinate chelate (90.9%) in one head-to-head 40-child matched-group trial (apparent bioavailability was calculated, not isotope-measured). In a randomized isotope study, ferrous fumarate did not differ significantly from ferrous sulfate in non-anemic women and children.
Source: Pineda O, Ashmead HD. 2001, Nutrition 17(5):381-384, PMID 11377130; Harrington M et al. 2011, PMID 20842166
Elemental fraction: 11.6% (Fe(C6H11O7)2 x 2H2O, dihydrate (standard commercial/USP form))
Commonly used clinically as a milder-tolerated alternative to sulfate, but no comparative human bioavailability citation was independently verified.
Source: none located (no human absorption comparison of ferrous gluconate vs sulfate found)
Bioavailability depends on food source and matrix, not a fixed stoichiometric ratio.
Elemental fraction: 27.4% (Fe(C2H4NO2)2, anhydrous bisglycinate (theoretical pure-compound value; branded Ferrochel is standardized to ~20% Fe, likely a diluted/standardized powder rather than pure chelate))
Apparent bioavailability 90.9% vs. 26.7% for ferrous sulfate in a 40-child matched-group trial of iron-deficiency anemia (not stated as randomized); only the chelate group showed a significant ferritin increase.
Source: Pineda O, Ashmead HD. 2001, Nutrition 17(5):381-384, PMID 11377130
Reference values
- RDA (adult): 18 elemental mg — 8mg (men, all ages; women 51+); 18mg (women 19-50)
- Tolerable Upper Intake Level (adult): 45 elemental mg — Based on gastrointestinal distress from supplemental iron salts
- Studied clinical dose range: 60–120 mg
- Stoffel NU et al. 2017, Lancet Haematol 4(11):e524-e533, PMID 29032957 -- two open-label RCTs in iron-depleted women (n=40 and n=20) using isotopically labelled ferrous sulfate at 60mg and 120mg Fe doses; alternate-day dosing increased fractional (21.8% vs 16.3%) and cumulative total absorption (175 vs 131mg), about 34%, vs consecutive-day dosing. The 60mg low end and 120mg high end are the doses tested in that paper.