Sodium Thioglycolate

As part of its re-review process Cosmetic Ingredient ReviewThe Cosmetic Ingredient Review (CIR) was established in 1976 as an independent safety review program for cosmetic ingredients. The CIR Expert Panel consists of independent experts in dermatology, toxicology, pharmacolgy and veterinary medicine. The CIR includes participation by the U.S. Food & Drug Administration and the Consumer Federation of America. (CIR) re-opened the report on Ammonium Thioglycolate, Glyceryl Thioglycolate and Thioglycolic Acid. Because of similarities in stucture and use in personal care products, the CIR Expert Panel added additional thioglycolate sats and esters to this report. The new report was finalized in 2007 with the following conclusion. Based on the available data, Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate and Thioglycolic Acid are safe for use in hair straighteners, permanent waves, hair styling products, and hair dyes and colors at concentrations up to 15.2% (as Thioglycolic Acid). Hair dressers should avoid skin contact and minimize consumer skin exposure. Calcium Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate and Thioglycolic acid in depilatories are safe when formulated to be non-irritating under conditions of recommended use.

CIR Safety Review: The CIR Expert Panel reviewed the safety of Thioglycolic Acid Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate and Sodium Thioglycolate. These ingredients are used predominantly in permanent waving lotions at concentrations up to 15.2% (as Thioglycolic Acid). At use concentrations, Thioglycolic Acid and it salts and esters were only slightly toxic in acute single oral and dermal exposures. In repeated dermal tests for extended periods of exposure, these ingredients were toxic. Commercial permanent wave products produced transient conjunctival redness to both rinsed and unrinsed eyes. The results of skin testing for irritation and sensitization of these Thioglycolates depend on the type of test system used. Under occlusive patch testing, the data indicate that these ingredients are cumulative irritants and possibly weak sensitizers, but not under semi-occlusive test conditions.

In clinical patients, mainly hairdressers, Glyceryl Thioglycolate elicited allergic reactions at concentrations down to 0.25%. The CIR Expert Panel noted that all method of hair removal, including waxing, shaving and depilatory products may produce trasient dermal irritation. In their experience, when used according to package directions, depilatory products containing Thioglycolic Acid and/or its salts are practically non-irritating. The CIR Expert Panel concluded that Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate and Thioglycolic Acid are safe for use in hair straighteners, permanent waves, hair styling products, and hair dyes and colors at concentrations up to 15.2% (as Thioglycolic Acid). Hair dressers should avoid skin contact and minimize consumer skin exposure. Calcium Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate and Thioglycolic acid in depilatories are safe when formulated to be non-irritating under conditions of recommended use. Health Canada permits the use of Thioglycolic Acid and its salts in hair waving and straightening products at concentrations equal to or less than 8% with a pHA measurement of the acidity or basicity of a substance. pH is the negative logarithm (base 10) of the concentration of hydrogen ions in solution. Water has a concentration of hydrogen ions of 1.0 x 10-7, and thus has a pH of 7. A pH of 7 is considered neutral, a pH lower than 7 is considered acidic, and a pH higher than 7 is considered basic. of 7 to 9.5, in hair waving and straightening products for professional use at concentrations equal to or less than 11% with a pH of 7 to 9.5 and and in depilatory products at concentrations equal to or less than 5% with a pH of 7 to 12.7.

Directions for use and product labels must be included.

Thioglycolic Acid and its salts and esters are listed in the Cosmetics Regulation of the European Union and may be used in hair waving or straightening products at 8% for general use and 11% for professional use when the pH is between 7 and 9.5. Thioglycolic Acid and its salts can also be used in depilatories and other hair products which are removed after application at 5% (pH 7 to 12.7) and 2% (pH 7 to 9.5), respectively. Other limitations apply and Conditions of Use and Warnings must be printed on the product label.

EU Cosmetic Regulation