Ingredient Dictionary

TETRASODIUM PYROPHOSPHATE

Sodium diphosphate is an inorganic sodium salt comprised of a diphosphate(4) anion and four sodium(1+) cations.

How much products actually contain

No product states its amount yet.

Of the products containing it, 22 list it before the 1% line and 14 after it (usually 1% or less).

Products using this ingredient

12 of 35 confirmed · likeliest to carry enough first · See all 35

Definition

Sodium diphosphate is an inorganic sodium salt comprised of a diphosphate(4) anion and four sodium(1+) cations. More commonly known as tetrasodium pyrophosphate, it finds much use in the food industry as an emulsifier and in dental hygiene as a calcium-chelating salt. It has a role as a chelator, a food emulsifier and a food thickening agent. It contains a diphosphate(4-).

Source: PubChem

US FDA substance register · UNII O352864B8Z · registered name SODIUM PYROPHOSPHATE · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Tetrasodium Pyrophosphate is the inorganic salt that conforms to the formula

Cosmetic roles

Stops powders from cakingANTICAKINGCares for the mouthORAL CAREKeeps pH steadyBUFFERINGBinds metal ions to prevent spoilageCHELATING

Safety & regulatory references

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

Reviewed by CIR: Safety Assessment of Phosphoric Acid and Its Salts as Used in Cosmetics

Source: US Cosmetic Ingredient Review (CIR)

More data — names, identifiers, properties, test records, literature

Official labels & definitions

JCIA labelling name ピロリン酸４Ｎａ: 本品は、ピロリン酸の四ナトリウム塩であり、次の化学式で表される。

Source: JCIA labelling names (Japan)

Names & identifiers

TETRASODIUM PYROPHOSPHATEINCI테트라소듐파이로포스페이트Korean label name (MFDS standard)Diphosphoric acid, tetrasodium saltSynonymピロリン酸４ＮａJapanese labelling name

CAS No.chemical registry number: 7722-88-5
EC No.EU chemical inventory number: 231-767-1
DTXSIDUS EPA chemical ID: DTXSID9042465
DTXCIDUS EPA compound ID: DTXCID7022465

IUPAC: Tetrasodium diphosphate
Molecular formula: Na4O7P2
Molecular weight: 265.9 g/mol

Measured properties

Appearance: Tetrasodium pyrophosphate appears as odorless, white powder or granules. mp: 995 °C. Density: 2.53 g/cm3. Solubility in water: 3.16 g/100 mL (cold water), 40.26 g/100 mL boiling water. Used as a wool de-fatting agent, in bleaching operations, as a food additive. The related substance tetrasodium pyrophosphate decahydrate (Na4P2O7*10H2O) occurs as colorless transparent crystals. Loses its water whe · Liquid, Other Solid, Dry Powder, Large Crystals
Odour: Odorless. · odourless
Boiling point: Decomposes (NIOSH, 2024) · Decomposes
Melting point: 1810 °F (NIOSH, 2024) · 988 °C
Solubility: 7 % at 77 °F (NIOSH, 2024) · Soluble in water. Insoluble in ethanol
Density: 2.45 (NIOSH, 2024) - Denser than water, will sink · 2.534
pH: Between 9,8 and 10,8 (1 % solution) · 10.2 (1% SOLN)
Colour: colourless, white
Melting/freezing point: 988 ℃
Vapour pressure: 0.0000000206 ㎜Hg (25℃est.)
Water solubility: 58.5 (20℃, pH 9.9, g/L)
Relative density: 2.62 (21℃)
n-Octanol/water partition coefficient (Kow): -10.45 (est.)
Molecular weight: 266

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 125 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Chelating agent56
Emulsifier22
pH regulating agent12
Pharmaceutical (EPA)10
Anti-caking agent4
Thickening agent4
Dispersing agent4
Processing aids not otherwise specified2

9 other uses

Corrosion inhibitor2
Lubricating agent2
Abrasive1
Flavouring and nutrient1
Drier1
Cleaning agent1
Oxidizing agent1
Softener and conditioner1
Humectant1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

4 skin studies and 4 eye studies are on record.

Classed as moderate1Classed as low1

The studies disagree (the most common conclusion covers 50%), so they do not establish that this ingredient is irritating. These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 8 studies

Studies Indicate No Significant Irritation
skin irritation: in vivo · Screening · other guideline: FMC Non-Definitive Primary Skin Irritation Protocol (Number 10) according to OECD Guideline 404 (Acute Dermal Irritation / Corrosion) equivalent or similar to
Classification not possible
Skin Sensitization · Screening
Category 2
Skin Irritation · Screening
Category 6.3A (Category 2)
Skin Irritation · Read Across
Corrosive or Irritation Persists for > 21 days
eye irritation: in vivo · Screening · OECD Guideline 405 (Acute Eye Irritation / Corrosion) according to
Category 2A
Eye Irritation · Screening
Category 6.4A (Category 2A)
Eye Irritation · Read Across
Serious eye damage/eye irritation - Category 1
Eye Irritation · Screening