Stearoyl Sarcosine

What Is It?

The acyl sarcosines (Cocoyl Sarcosine, Lauroyl Sarcosine, Myristoyl Sarcosine, Oleoyl Sarcosine, Stearoyl Sarcosine) are modified fatty acids, and acyl sarcosinates (Sodium Cocoyl Sarcosinate, Sodium Lauroyl Sarcosinate, Sodium Myristoyl Sarcosinate, Ammonium Cocoyl Sarcosinate, Ammonium Lauroyl Sarcosinate) are their respective salts. In cosmetics and personal care products, these ingredients are used in the formulation of shampoos, bath, cleansing and shaving products.

Why Is It Used?

Acyl sarcosines and sarcosinates enhance the appearance and feel of hair, by increasing hair body, suppleness, or sheen, or by improving the texture of hair that has been damaged physically or by chemical treatment. They also clean skin and hair by helping water to mix with oil and dirt so that they can be rinsed away.

Scientific Facts

The acyl sarcosines are prepared from fatty acids and sarcosine, which is a breakdown product of creatine or caffeine. These modified fatty acids impart greater solubility, crystallinity and acidity compared to the parent fatty acid, i.e., coconut acid, oleic acid, lauric acid, and myristic acid.

Safety Information

The Food and Drug Administration (FDA) reviewed the safety of Lauroyl Sarcosine, Stearoyl Sarcosine, and Sodium Lauroyl Sarcosinate and approved their use as indirect food additives for use in cellophane having incidental contact with food. N-Acyl Sarcosines such as Lauroyl, Oleoyl, or Sarcosines with the combined fatty acids of coconut oil have been approved as anti-static and/or anti-fogging agents for food packaging material. The safety of acyl sarcosines and sarcosinates has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel.

The CIR Expert Panel evaluated the scientific data and concluded that Cocoyl Sarcosine, Lauroyl Sarcosine, Myristoyl Sarcosine, Oleoyl Sarcosine, Stearoyl Sarcosine, Sodium Cocoyl Sarcosinate, Sodium Lauroyl Sarcosinate, Sodium Myristoyl Sarcosinate, Ammonium Cocoyl Sarcosinate and Ammonium Lauroyl Sarcosinate were safe as used in rinse-off products, and safe for use in leave-on products at concentrations of 5% or less.

The data were insufficient to determine the safety for use in products where the sarcosines and sarcosinates were likely to be inhaled. The CIR Expert Panel cautioned that these ingredients may be susceptible to nitrosamine formation.

CIR Safety Review: The CIR Expert Panel conducted previous safety assessments on each of the fatty acids that appear in these Acyl Sarcosines and Sarcosinates (coconut acid, oleic acid, lauric acid, myristic acid, stearic acid). In each case the fatty acid was safe for use in cosmetic formulations. The acyl sarcosines and sarcosinates had low oral toxicity. They were not mutagenic. These ingredients were nonirritating and nonsensitizing to skin, although they enhanced the penetration of other ingredients through the skin.

The CIR Expert Panel concluded that the acyl sarcosines and sarcosinates were safe as used in rinse-off products. They may be safely used in leave-on products at concentrations up to 5%, the highest concentration tested in clinical irritation and sensitization studies. Because of the absence of data on inhalation toxicity of these ingredients, the CIR Expert Panel concluded that the available data were not sufficient to support the safety of acyl sarcosines and sarcosinates as cosmetic ingredients in products where they are likely to be inhaled.

The CIR Expert Panel also acknowledged that sarcosine may be nitrosated to form N-nitrososarcosine, a potentially carcinogenic compound. Therefore, these ingredients should not be used in cosmetics and personal care products in which N-nitroso compounds may be formed.

More information about nitrosamines.

Link to FDA Code of Federal Regulations for N-acyl sarcosines

The aryl sarcosines and sarcosinates 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.

EU Cosmetic Regulation

More Scientific Information

Cocoyl Sarcosine, Lauroyl Sarcosine, Myristoyl Sarcosine, Oleoyl Sarcosine, Stearoyl Sarcosine, Sodium Cocoyl Sarcosinate, Sodium Lauroyl Sarcosinate, Sodium Myristoyl Sarcosinate, Ammonium Cocoyl Sarcosinate and Ammonium Lauroyl Sarcosinate are all N-acyl derivatives of sarcosine. In cosmetics and personal care products, the acyl sarcosines and their salts function as hair conditioning agents and surfactant – cleansing agents.

Resources

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