Ferrous gluconate

INS 579CAS 6047-12-7

Used as a colour retention agent.

Ferrous gluconate is an iron fortificant and also the additive that darkens ripe olives to a uniform black. It is one of the few additives whose colour use is better known than its nutritional one.

Where it is and isn’t permitted

Status of Ferrous gluconate by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1308and 1 further provisionretrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

1 food category

highest permitted level 150 mg/kg

CXS 192-1995 Table One, INS 579, food category 04.2.2.3retrieved 2026-09-07

What it is made from

Made by reacting an iron salt with fermentation-derived gluconic acid.

  • Vegan
  • Vegetarian
CAS registry number
6047-12-7
InChIKey
OKGNXSFAYMSVNN-SYAJEJNSSA-L
PubChem
CID 198008

Every name it appears under

27 recorded names. A label may use any of them.

INS number

  • 579

CAS registry number

  • 22830-45-1
  • 6047-12-7

As it appears in regulation

  • Ferrous gluconate

Other names

  • Apo-Ferrous Gluconate
  • CCRIS 7332
  • D-Gluconic acid, iron(2+) salt, dihydrate
  • D-GLUCONIC ACID, IRON(2+) SALT, HYDRATE (2:1:2)
  • D-GLUCONIC ACID, IRON(II) SALT (2:1), DIHYDRATE
  • D-Gluconic acid, iron(II) salt, dihydrate
  • Enterued (TN)
  • Ferrous gluconate (USP)
  • Ferrous gluconate [USP]
  • Ferrous gluconate dihydrate
  • Gluconic acid, iron(2+) salt, dihydrate
  • GLUCONIC ACID, IRON(2+) SALT, DIHYDRATE, D-
  • Gluconic acid, iron(II) salt, hydrate (2:1:2)
  • IRON (AS FERROUS GLUCONATE) [VANDF]
  • IRON (II) DI-D-GLUCONATE DEHYDRATE
  • Iron(2+) D-gluconate--water (1/2/2)
  • iron(2+);(2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoate;dihydrate
  • Iron(II) D-gluconate dihydrate
  • IRON(II) GLUCONATE (1:2) DIHYDRATE
  • Iron(II) gluconate dihydrate
  • IRON, BIS(D-GLUCONATO-.KAPPA.O1,.KAPPA.O2)-, HYDRATE (1:2)
  • Iron, bis(D-gluconato-O1,O2)-, dihydrate
  • OKGNXSFAYMSVNN-SYAJEJNSSA-L

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07
  • gsfa retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/ferrous-gluconate.json