Citric Acid, Anhydrous, 1 kg

Anhydrous Citric Acid

Citric acid in anhydrous form is a pH regulator added to water-based cosmetic formulations when the finished blend needs to be acidified to a value suitable for skin. Its second major application is in bath bombs and effervescent salts, where it creates a fizzing reaction together with sodium bicarbonate. It is supplied in cosmetic and food-grade quality, making it suitable for household cleaning products and kitchen use as well.

What it is used for

• pH adjustment – the most common reason it is added. Tonics, shampoos, shower gels and emulsions often end up with a higher pH than desired after the ingredients are mixed. A small amount of dissolved citric acid pulls it into a more acidic range; the recommended range is pH 3 – 6 depending on the product type.
• Chelating agent – binds metal ions present in water and raw materials. This helps maintain the colour and fragrance stability of the formulation and supports the effectiveness of the preservation system.
• Exfoliation – at low concentrations it promotes gentle shedding of dead skin cells and a fresher complexion. When used for this purpose, the final pH and dosage need to be monitored.
• Antioxidation – helps protect the formulation against oxidation.
• Effervescent effect – in dry mixtures with sodium bicarbonate it is the acidic component that triggers fizzing upon contact with water.

Use in formulation

The powder is miscible with water, partially soluble in alcohol and insoluble in oil. For water-based formulations it is therefore dissolved in the aqueous phase, or a water-based stock solution is prepared, added drop by drop while the pH is measured continuously. This allows the value to be fine-tuned precisely and without the risk of over-acidifying the formulation.

The recommended dosage is 0.1 – 2 %. For routine pH correction, the lower end of the range is sufficient; higher doses are used for exfoliating products or where the starting pH is strongly alkaline. It is added to the water phase, during the cooling phase, or additionally to the finished blend; the processing temperature should be below 40 °C.

In bath bombs, the dry powder form is used. The mixture with sodium bicarbonate is only activated upon contact with water, so it is mixed and pressed in a dry environment. Each manufacturer adjusts the ratio of ingredients and the amount of binder according to their own formulation.

It is compatible with anionic, amphoteric and non-ionic surfactants, so it is commonly used to acidify shampoos, shower gels and liquid soaps. It is suitable for both rinse-off and leave-on products and for formulations for all skin types.

Suitable for products such as

• Tonics, facial waters and water-based moisturising serums where pH needs to be adjusted.
• Shampoos, shower gels, liquid soaps and other rinse-off products with surfactants.
• Bath bombs, effervescent salts and fizzing shower tablets.
• O/W creams and lotions, added at the end to the water phase or during cooling.
• Exfoliating tonics and peels at low dosage.
• Household cleaning products.
• Food use at home, for example for adjusting acidity.

Good to know

Citric acid is a strong regulator; very little is needed for acidification. The stock solution is added gradually, with a measurement after each addition. If you are unsure about the behaviour of a specific formulation, test it in a small trial batch.

The anhydrous form attracts moisture from the air. Keep the container tightly closed, open it only for the minimum necessary time when weighing, and when making bath bombs work in a dry environment — otherwise the mixture will start to clump and lose its effervescence.

Frequently asked questions