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Ingredient dictionary

Tetrasodium Pyrophosphate

Also listed as: Sodium Pyrophosphate

A salt that binds calcium and magnesium in hard water so they don't interfere with a formula, and helps keep pH steady. It is on the label of 1 product in our library. Checked against our library November 6, 2026.

What Tetrasodium Pyrophosphate does

  • Binds calcium and magnesium in water
  • Helps keep pH steady
  • Helps cleansers work in hard water

Tetrasodium pyrophosphate is a white powder made by heating sodium phosphate salts together until water is driven off and phosphate units join into pyrophosphate. Once it dissolves, it grabs onto calcium and magnesium ions, the minerals that make tap water hard. Those minerals can react with soap and other surfactants and leave dull lather or film, so binding them keeps a cleanser working as intended.

Formulators also value it as a mild buffer, which helps hold a product's pH steady over time. Because it works in the background, it is rarely noticed by the person using the product. It doesn't add scent, color or a strong feel on the skin. It also appears in some toothpastes, where it is used for its mineral-binding job.

Good for

Rinse-off cleansers and formulas that use hard tap water, where minerals might otherwise dull lather or leave residue.

Frequently asked questions

Is tetrasodium pyrophosphate safe?

It is widely used in cosmetics and is generally well tolerated by most people. Like any ingredient, a patch test is a sensible step if your skin is sensitive. For specific concerns, a dermatologist or pharmacist is the best guide.

Does tetrasodium pyrophosphate help with hard water?

Yes, that is its main job in many formulas. It binds calcium and magnesium so they cannot interfere with surfactants. This helps cleansers lather more evenly in areas with hard water. It does not soften your tap water at home.

Products with Tetrasodium Pyrophosphate

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Amazon UK prices as of 6 November 2026, 04:30 GMT; Amazon sets the final price at checkout.