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Ferrous fumarate

Ferrous fumarate suppliers and sourcing guide

Ferrous fumarate is the iron (II) salt of fumaric acid, made by mixing hot solutions of ferrous sulfate and sodium fumarate and collecting the precipitate. It is an odorless reddish-orange to reddish-brown powder with about one-third iron by weight, one of the highest iron contents among iron salts. It is only slightly soluble in water, so brands buy it as powder or granules for tablets, capsules and dry fortification premixes rather than clear liquids.

See suppliersWhat to ask for on the COA
Also known as
Iron (II) fumarate · Ferrous fumarate USP · CAS 141-01-5
Facts checked
November 2026

Forms and grades of ferrous fumarate

Suppliers sell different products under the same name. Specify the one you need.

  • USP or FCC powder

    The standard fine powder, used in tablets, capsules and premixes.

  • Granulated grades

    Granules made for direct compression and better flow on tablet presses.

  • Micronized

    Small-particle grades for fortified flours and food premixes where even distribution matters.

  • Encapsulated

    Ferrous fumarate coated with fat or another barrier to limit color and flavor changes in fortified foods.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Assay
Ferrous fumarate content by ceric sulfate titration on the dried basis, against the USP or Food Chemicals Codex specification.
Ferric iron
A limit on oxidized iron, which indicates exposure to air and moisture.
Loss on drying
Moisture of the powder.
Sulfate
A limit on sulfate carried over from the ferrous sulfate used in manufacture.
Lead, arsenic and mercury
Heavy metals by ICP-MS against the compendial or supplier limits.
Particle size
Sieve or laser diffraction data for micronized and granulated grades.

Storage, lots and expiry

Storage and shelf life

Ferrous fumarate is fairly stable, but it should be stored in tightly closed containers in a cool, dry place away from light and oxidizing materials. Keep opened packs sealed to limit oxidation. Shelf life is set by the supplier's specification, and aged lots are retested for assay and ferric iron.

Lots and expiry dates

Record the assay and particle size for each lot, and keep micronized, granulated and encapsulated grades on separate item codes. Its color can tint light-colored tablets and foods, so check shade when switching suppliers.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • 21 CFR 184.1307d affirms ferrous fumarate as GRAS for use in food as a nutrient supplement with no limitation other than current good manufacturing practice, and allows its use in infant formula.

    Source: ecfr.gov (opens in a new tab)

  • Health Canada's Multi-Vitamin/Mineral Supplements monograph for natural health products lists iron (II) fumarate among the source ingredients for iron (Table 2).

    Source: webprod.hc-sc.gc.ca (opens in a new tab)

  • 21 CFR 101.17(e) requires dietary supplements in solid oral dosage form that contain iron or iron salts as an iron source to carry a boxed accidental-overdose warning statement.

    Source: ecfr.gov (opens in a new tab)

  • 21 CFR 101.9(c)(8)(iv) sets the Reference Daily Intake for iron at 18 mg for adults and children 4 years and older.

    Source: ecfr.gov (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Ferrous fumarate suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking ferrous fumarate suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

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Frequently asked questions

What forms of ferrous fumarate can brands buy?

Common forms include uSP or FCC powder, granulated grades, micronized and encapsulated. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for ferrous fumarate include?

Expect assay, ferric iron, loss on drying, sulfate, lead, arsenic and mercury and particle size, each with its method, specification and result for that lot.

How should ferrous fumarate be stored?

Ferrous fumarate is fairly stable, but it should be stored in tightly closed containers in a cool, dry place away from light and oxidizing materials. Keep opened packs sealed to limit oxidation. Shelf life is set by the supplier's specification, and aged lots are retested for assay and ferric iron.

What is the regulatory status of ferrous fumarate?

21 CFR 184.1307d affirms ferrous fumarate as GRAS for use in food as a nutrient supplement with no limitation other than current good manufacturing practice, and allows its use in infant formula. Health Canada's Multi-Vitamin/Mineral Supplements monograph for natural health products lists iron (II) fumarate among the source ingredients for iron (Table 2). 21 CFR 101.17(e) requires dietary supplements in solid oral dosage form that contain iron or iron salts as an iron source to carry a boxed accidental-overdose warning statement. 21 CFR 101.9(c)(8)(iv) sets the Reference Daily Intake for iron at 18 mg for adults and children 4 years and older.

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