What Is It?

Alpha amino acids are the building blocks of proteins. The structures of all the alpha amino acids include a carboxylic acid with an amine (NH2) group on the adjacent carbon. The 20 most common amino acids found in proteins are: Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine. The amino acids and simple salts of amino acids, such as Arginine HCl, Calcium Aspartate, Calcium Glycinate, Cysteine HCl, Dipotassium Aspartate, Histidine HCl, Lysine HCl, Magnesium Aspartate, Magnesium Glycinate, Potassium Aspartate, Sodium Aspartate, Sodium Glutamate and Sodium Glycinate may be used in cosmetics and personal care products. Products in which these ingredients may be found include baby products, bath products, cleansing products, eye makeup, shaving preparations and hair and skin care products.

Why Is It Used?

In cosmetics and personal care products, the amino acids function primarily as hair conditioning agents and skin conditioning agents – miscellaneous.

Scientific Facts

Amino acids, normally found in dietary protein, are released as the protein is digested in the gastrointestinal tract. Eight of the amino acids, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine are considered essential and must be obtained through the diet.

Safety Information

The Food and Drug Administration (FDA) lists the amino acids, including their hydrochloride (HCl), sodium and potassium salts as food additives permitted to be directly added to food. The FDA permits Glycine to be used in Over-the-Counter antacid drug products. The safety of the alpha amino acids and their simple salts has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that these ingredients were safe as used in cosmetics and personal care products.

CIR Safety Review:

The normal presence of these ingredients in the body, and their use as direct food additives led the CIR Expert Panel to focus their review only on dermal irritation and sensitization data. Dermal data on products containing these ingredients indicated that the amino acids are not dermal irritants or sensitizers. The CIR Expert Panel noted that some individuals have issues with dietary Sodium Glutamate and Phenylalanine. The CIR Expert Panel determined that the concentrations of these amino acids used in cosmetic products are lower than levels that would result in significant exposure.

Based on the available data, the CIR Expert Panel concluded that the amino acids and their simple salts are safe for use in cosmetic products.

FDA: Link to Code of Federal Regulations for the amino acids.

The amino acids and their simple salts 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

Bacterial fermentation is the primary method of manufacture used to produce Glutamine, Histidine, Leucine, Isoleucine, Proline, Serine, Arginine, Tryptophan, Phenylalanine, Threonine, Glutamic Acid and Lysine. Enzymatic catalysis is used to produce Alanine, Methionine, Valine and Aspartic Acid, while Glycine chemically synthesized from choroacetic acid and ammonia. Purification after complete hydrolysis of proteins is the method used to produce Asparagine and Tyrosine.


Find out more about the regulation of over-the-counter drugs by the Food and Drug Administration

OTC Drug Home Page:

Information about OTC Drug monographs:

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