What Is It?

Ammonia (H3N) is a gas. When dissolved in water, Ammonia forms Ammonium Hydroxide (H5NO). Ammonia and Ammonium Hydroxide are used in a large variety of products including hair dyes, hair bleaching products, shaving cream and hair grooming products.

Why Is It Used?

Ammonia and Ammonium Hydroxide function as pH adjusters. When used in hair dyes and colors, Ammonia helps prepare the hair so that the dye can diffuse into the hair shaft. Ammonium Hydroxide may also function as a denaturant.

Scientific Facts

Ammonia is a colorless gas with a very pungent odor. Ammonia is found throughout the environment including in air, water, soil and in plants and animals including humans. Ammonium Hydroxide is the name given to a solution of Ammonia in water. Ammonium Hydroxide does not exist as an isolated chemical.

Safety Information

The Food and Drug Administration (FDA) includes Ammonium Hydroxide on its lists of direct food substances affirmed as Generally Recognized as Safe (GRAS). It can be used at levels not to exceed good manufacturing practices. Both Ammonia and Ammonium Hydroxide are FDA approved indirect food additives. Ammonia may be used as a defoaming agent used in the manufacture of paper and paperboard used to package food, and Ammonium Hydroxide may be used in polymers that come in contact with food.

Ammonium Hydroxide and Ammonia are identified as food additives that may be safely used following prescribed conditions.

Link to FDA Code of Federal Regulations

Ammonia has been evaluated by the Agency for Toxic Substance and Disease Registry, which is part of the Centers for Disease Control and a toxicology fact sheet

Ammonia is listed in the Cosmetics Directive of the European Union (see Annex III, Part I). It is allowed for use at a maximum concentration of 6% as NH3, and must be labeled, contains Ammonia if the concentration is above 2%.

EU Cosmetic Regulation

More Scientific Information

Ammonia used commercially can be anhydrous ammonia (not dissolved in water) or an aqueous solution of ammonia and water referred to as Ammonium Hydroxide. Anhydrous ammonia must be stored under pressure or at low temperature to remain a liquid.