Maleic Acid

What Is It?

Maleic Acid occurs as colorless to white crystals or crystalline powder and has an acidic odor. In cosmetics and personal care products, Maleic Acid is used in the formulation of hair and bath products and shaving creams.

Why Is It Used?

Maleic Acid is used to control the pH of cosmetics and personal care products.

Scientific Facts

In addition to its use in cosmetics and personal care products, Maleic Acid is used to finish wool, cotton and silk. Maleic Acid is also reported to be used as a preservative for oils and fats.

Safety Information

The Food and Drug Administration (FDA) has reviewed the safety of Maleic Acid and approved its use as an indirect food additive as component of adhesives and coatings that have contact with food. The safety of Maleic Acid has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Maleic Acid was safe as used in cosmetic formulations as a pH adjustor.

CIR Safety Review: Maleic Acid failed to induce any significant increases in genotoxicity in bacteria. Maleic Acid at high concentrations caused permanent opacity of the eye. A weaker solution caused cloudiness of the cornea, but no lasting injury. Application of Maleic Acid (pH not stated) to the volar forearm and of 21 women produced an inflammatory response at 24 hours and 48 hours which varied from minimal erythema to marked erythema with marked vesiculation.

Maleic Acid (pH not stated) applied to one forearm daily for a period of 6 weeks to 50 human subjects, produced acute vesicular dermatitis in 17 subjects. Only 5 of the remaining subjects accommodated to the treatment, the remainder had varying degrees of inflammation or hyperirritable skin. While Maleic Acid itself may be a dermal and/or ocular irritant, its use as a pH adjustor in cosmetic formulations dictates that most of the acid will be neutralized into various maleate salts.

Therefore, the concentration of free Maleic Acid is expected to be low, and dermal or systemic toxicity is not expected to be a concern. The safety of Maleic Acid as a pH adjustor should not be based on the concentration of use, but on the amount of free Maleic Acid that remains after neutralizing the formulation.

There is no reason to expect this ingredient to induce any toxicity when used for this purpose.

Link to FDA Code of Federal Regulations for Maleic Acid

Maleic Acid may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European Union.

Link to the EU Cosmetic Regulation:…

More Scientific Information

Maleic Acid is a dicarboxylic acid. In cosmetics and personal care products, Maleic Acid functions as a pH adjuster.


Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging:

Food Contact Substances:…

Substances Generally Recognized As Safe (GRAS):

Search the Code of Federal Regulations

EU Cosmetics Inventory