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What is "Disodium Phosphate" and what is its purpose?

What is "Disodium Phosphate" and what is its purpose?

Disodium Phosphate, also known as disodium hydrogen phosphate or sodium hydrogen phosphate (with the chemical formula Na2HPO4), is derived from the combination of phosphoric acid (H3PO4) with soda ash. Once crystallised and purified, it is used in various skincare products. The question that arises is: what is the use of disodium phosphate? Here's what you need to know about this ingredient.

Summary
Published November 5, 2021, updated on February 1, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 4 min read

Everything you need to know about Disodium Phosphate

Derived from phosphate minerals, the salts of sodium phosphoric acid help to regulate the skin's pH. They are used in small quantities.

Disodium Phosphate has masking and descaling properties. It is also known by the name of:

  • Disodium hydrogen phosphate;

  • Dibasic Sodium Phosphate;

  • Food additive E339(ii);

  • Disodium monophosphate.

Similar to monobasic sodium phosphate and trisodium phosphate (tribasic sodium phosphate), disodium phosphate (dibasic sodium phosphate) presents itself as an odourless and hygroscopic powder, of white colour.

Disodium Phosphate: What is its purpose?

Disodium phosphate is used as a laxative. Its functions are as follows:

  • It stabilises the pH of skincare products;

  • It prevents the corrosion of the packaging.

This is about:

  • Regarding a pH regulator: it is used to stabilise the pH of a skincare product;

  • Of a corrosion accelerator;

  • Of a masking agent.

This synthetic ingredient is present in:

  • Adult sun creams;

  • Skincare for the body and face;

  • Hair dyes;

  • Mouthwashes;

  • The conditioners;

  • Eau de Cologne;

  • The make-up;

  • Toothpastes: When combined with fluoride and phosphoric acid, disodium phosphate helps to prevent the dissolution of enamel.

Furthermore, it can also be utilised in the production of perfumes.

As a food additive under the designation E339(ii), disodium phosphate is used to enhance the characteristics of food, namely:

  • The cooking performance;

  • The nutritional value.

It is used as an emulsifier in certain foods such as cheeses. It is also present in:

  • Evaporated milk;

  • Canned sauces;

  • The chocolates.

Furthermore, disodium phosphate is used in numerous applications:

  • In the treatment of water and textiles: it delays the formation of scale;

  • In surface treatment: it is used to inhibit corrosion;

  • In detergents;

  • In the pharmaceutical and food industry (as a cooking accelerator or as an agglomerating agent).

Which ingredients are incompatible with Disodium Phosphate?

Disodium phosphate is incompatible with:

  • The monohydrated chloral;

  • Resorcinol;

  • Lead Acetate;

  • Strong acids.

Body and facial care products containing disodium phosphate should be stored in a cool place within tightly sealed containers, protected from heat and light.

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