Stearic acid, or stearin, is a white crystalline substance, odorless. It is non-toxic and is found in many fats and oils. The chemical formula of stearin looks like this CH3 (CH2) 16COOH.
Where is stearin used?
Stearic acid is extracted from animal fats and is used in the production of rubber compounds, as well as in the pharmaceutical industry, in analytical chemistry as a functional chemical and as a chemical raw material.
The existence of stearic acid became known in 1816, when it was discovered in lard by the French chemist Chevreul.
However, the largest area of application of stearin today is the cosmetic industry, in the production of soaps, detergents, toothpastes, creams and hair dyes. In particular, stearic acid salts - stearates - are an integral part of most soaps. At the same time, stearic acid itself is included in the composition of many creams, lotions and other caring cosmetics.
Stearin has several functions in cosmetics. Firstly, it is a good emulsifier and stabilizer for unstable cosmetic mixtures, which can disintegrate into separate phases in the absence of emulsifiers. Secondly, stearin makes clear liquids opaque. Finally, stearates act as thickeners in the manufacture of soaps and solid cosmetics (for example, antiperspirant deodorants in the form of stickers).
Stearic acid is one of the most popular fatty acids in nature, which is part of energy storage - lipids, primarily of animal origin.
The concentration of stearin in creams and lotions usually ranges from 2 to 5%, and in solid soaps and deodorants in the form of stickers - within 25%. Often, stearic acid is used in conjunction with xanthan gum to bind ingredients in cosmetic emulsions.
The benefits and harms of stearin in cosmetics
Among the obvious benefits of stearin is its ability to make the skin silky smooth, moisturize it and significantly reduce moisture loss. Since stearic acid is initially a natural component that does not have toxic properties, there is practically no need to talk about its harm when consumed in cosmetics.
However, for oily and prone to inflammation of the skin, stearin can pose a serious danger as a strong comedogenic and acne-provoking substance. This is due to the ability of stearin to tightly clog the pores of the skin, which leads to the active growth of bacteria in the clogged pores.