Magnesium sulfate

INS 518CAS 10034-99-8

Used as a firming agent — Codex also lists it as flavour, enhancer.

Magnesium sulfate, better known as Epsom salt, is used in food as a firming agent, a nutrient source and to adjust water for brewing.

Where it is and isn’t permitted

Status of Magnesium sulfate 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 184.1443retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

1 food category

no numerical limit (good manufacturing practice)

CXS 192-1995 Table Three, INS 518and 1 further provisionretrieved 2026-09-07

What it is made from

Mined as epsomite or produced from magnesium-bearing minerals and sulfuric acid.

  • Vegan
  • Vegetarian
CAS registry number
10034-99-8
InChIKey
WRUGWIBCXHJTDG-UHFFFAOYSA-L
PubChem
CID 24843

Every name it appears under

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

INS number

  • 518

CAS registry number

  • 10034-99-8
  • 14457-55-7
  • 7487-88-9

As it appears in regulation

  • Magnesium sulfate

Other names

  • 50% MAGNESIUM SULFATE
  • Assured Epsom Salt
  • Bitter salt
  • Bittersalz
  • Conclyte-Mg (TN)
  • CVS foaming muscle relief
  • CVS muscle relief
  • Daily Care Epsom Salt
  • Epsom salt
  • Epsom salt(heptahydrate)
  • Epsom Salts Relief
  • Epsomite
  • Epsomite (Mg(SO4).7H20)
  • Equate Muscle Cramp and Spasm Relief
  • H14MgO11S
  • Harmon Core Values Epsom Salt
  • Heptahydrate Magnesium Sulfate
  • Humco Epson Salt
  • ITCHY SKIN ERUPTIONS
  • Magnesia sulphurica
  • Magnesii sulfatis heptahydras
  • MAGNESIUM (AS SULFATE)
  • MAGNESIUM SALFATE
  • Magnesium sufate heptahydrate
  • Magnesium sulfate (1:1) heptahydrate
  • Magnesium sulfate (USP)
  • MAGNESIUM SULFATE 7HYD XTL
  • Magnesium sulfate [USAN:JAN]
  • Magnesium sulfate heptahydrate
  • Magnesium sulfate heptahydrate (MgSO4.7H2O)
  • Magnesium sulfate heptahydrate ACS grade
  • Magnesium Sulfate Hydrate
  • Magnesium sulfate hydrate (JP18)
  • Magnesium Sulfate in 5% Dextrose
  • Magnesium Sulfate In Dextrose
  • Magnesium Sulfate in Water
  • Magnesium Sulfate In Water For
  • MAGNESIUM SULFATE, UNSPECIFIED FORM
  • Magnesium sulfate--water (1/1/7)
  • magnesium sulfate--water (1/7)
  • Magnesium sulphate
  • magnesium sulphate heptahydrate
  • MAGNESIUM SULPHATE, UNSPECIFIED
  • MAGNESIUM(II), SULFATE, HEPTAHYDRATE
  • MAGNESIUMSULFATEHEPTAHYDRATE
  • MgSO4*7H2O
  • MgSO4.7H2O
  • NuValu Epsom Salt
  • PHUEL
  • Rapidol Sal Inglesa
  • RECOVERY BALM-COOL HEAT
  • RECOVERY BALM-ORIGINAL
  • RECOVERY BALM-ULTRA
  • Relief Epsom Salt
  • Sulfuric acid magnesium salt (1:1), heptahydrate
  • sulfuric acid magnesium salt heptahydrate
  • Sulfuric acid, magnesium salt, hydrate (1:1:7)
  • Theraworx Relief
  • Theraworx Relief Muscle Cramp and Spasm Relief

Systematic names

  • Magnesium sulfate

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/magnesium-sulfate.json