What is Thioglycolic Acid?
Thioglycolic Acid, also known as mercaptoacetic acid, is a potent organic compound that is widely used in the cosmetic industry. It is a clear, colorless liquid with a strong, unpleasant odor. This compound is a part of the thiol group, characterized by the presence of sulfur and hydrogen in its molecular structure. Its chemical formula is C2H4O2S, which signifies the presence of two carbon, four hydrogen, two oxygen, and one sulfur atoms.
The use of Thioglycolic Acid in cosmetics dates back to the early 20th century. It was initially used in the textile industry for its reducing properties, but its potential in personal care products was soon recognized. The acid is synthesized through the reaction of chloroacetic acid with sodium hydrogen sulfide, resulting in a powerful reducing agent.
Thioglycolic Acid serves a similar purpose to other reducing agents in cosmetics, such as cysteamine hydrochloride and glutathione. However, it is more potent due to its sulfur content, which allows it to break down disulfide bonds in keratin, the protein that makes up hair and nails. This makes it particularly effective in hair waving, straightening, and depilatory products.
Despite its potency, Thioglycolic Acid is not a one-size-fits-all ingredient. It is most effective in products designed for hair treatment, where its reducing properties can alter the structure of the hair. It is also used as an antioxidant in various skincare products, where it helps to prevent oxidation and extend the product’s shelf life. However, it is not typically used in products like moisturizers or serums, as its strong reducing properties can be too harsh for sensitive skin.
Benefits and Uses
In this section, we will delve into the officially recognized benefits and uses of Thioglycolic Acid:
Antioxidant
As an antioxidant, Thioglycolic Acid plays a crucial role in protecting your skin from harmful free radicals. These free radicals, often a result of environmental stressors like pollution and UV rays, can cause premature aging and damage to the skin. By neutralizing these free radicals, Thioglycolic Acid helps to maintain the health and youthful appearance of your skin.
Depilatory
Thioglycolic Acid is also used as a depilatory agent in many hair removal products. It works by breaking down the protein structure of the hair, making it easier to remove. This means that products containing Thioglycolic Acid can provide a smooth and hair-free skin surface without the need for shaving or waxing.
Hair Waving or Straightening
One of the more unique uses of Thioglycolic Acid is in hair waving or straightening products. It works by breaking the disulfide bonds in the hair’s keratin structure, allowing it to be reshaped. Once the hair is set in its new shape and the product is rinsed out, the bonds reform, locking the hair in its new straight or wavy form.
Reducing
Thioglycolic Acid also functions as a reducing agent in cosmetic products. In this context, it helps to prevent oxidation, which can lead to color changes and degradation of the product. This ensures that the product maintains its effectiveness and aesthetic appeal over time.
It’s important to note that these benefits are based on the officially recognized and defined functions of Thioglycolic Acid. There may be other benefits and uses of this ingredient that go beyond the scope of these official functions.
Safety Profile
Thioglycolic Acid, also known as Mercaptoacetic acid, is a regulated ingredient in the cosmetics industry. In the European Union, its concentration in ready-for-use products is limited to 5% for hair waving or straightening products, and 2% for depilatory products. In the United States, the FDA has also set regulations on the use of Thioglycolic Acid in cosmetics, limiting its concentration to 11% in hair waving products and 5% in hair straightening products.
While Thioglycolic Acid is generally considered safe when used in regulated concentrations, it does have the potential to cause skin irritation and sensitization. It is therefore important to be aware of its potential allergenic potential. If you have sensitive skin or are prone to allergic reactions, it is recommended to perform a patch test before using products containing this ingredient.
- Redness
- Itching
- Burning sensation
- Skin irritation
A note for women who are pregnant and/or breastfeeding – There is currently a lack of data regarding the safety of topically applied Thioglycolic Acid during pregnancy or breastfeeding. As such, it is recommended to consult a healthcare professional for further advice before using products containing this ingredient.
Adverse reactions to Thioglycolic Acid are not common but can occur, especially in individuals with sensitive skin or those who are allergic to the ingredient. As always, it is recommended to perform a patch test before using any new product on a widespread basis.
This ingredient analysis has been commissioned by Truth In Skincare (TiS), an independent industry regulator. The analysis was conducted by a TiS-appointed industry consultant, using sources including the CosIng (Cosmetic Ingredient Database – by the European Commission), the Personal Care Products Council (PCPC), The US Food & Drug Administration (FDA), and other various publicly available sources.
