Why Is Steareth-20 Used?



What Is Steareth-20?

Steareth-20 is a synthetic ingredient that functions as a cleansing agent, a surfactant, and an emulsifier in a variety of cosmetics and skincare products.

The group of steareth ingredients are synthetic compounds that are created through a process known as ethoxylation, a chemical reaction in which ethylene oxide is added to a substrate. With steareth-20, the substrate is stearyl alcohol, a fatty alcohol that is derived from stearic acid. The number associated with the steareth-20 indicates the average number of repeating ethylene oxide units in the molecule. The steareth ingredients are waxy solids that can be used in cosmetics at concentrations of up to 25 percent.

Steareth 20

the good:Steareth-20 is a synthetic ingredient that functions as a cleansing agent, a surfactant, and an emulsifier to improve the texture and feel of formulations.

the not so good:It doesn’t provide any benefit to the condition of the skin.

Who is it for?All skin types except those that have an identified allergy to it.

Synergetic ingredients:Works well with most ingredients

Keep an eye on:As steareth-20 is produced through ethoxylation there is some controversy over its safety. However, steareth-20 is considered to be safe if it is used in the guidelines. More on this later.

Why Is Steareth-20 Used?

Steareth-20 is added to cosmetics and skincare products because it functions as a cleansing agent, a surfactant, and an emulsifier. These abilities help to improve the texture and feel of skincare products. 

Surfactants are ingredients that lower the surface tension between two substances, such as two liquids or a liquid and a solid. In skincare products, surfactants work to degrease and emulsify oils and fats and suspend dirt, allowing them to be washed away. This is possible because while one end of the surfactant molecule is attracted to water, the other end is attracted to oil. Thus, surfactants attract the oil, dirt, and other impurities that have accumulated on your skin during the day and wash them away. Due to these properties, steareth-20 can be found in many different cleansers and body washes.

Steareth-20 also functions as an emulsifier. An emulsifier is needed for products that contain both water and oil-based ingredients. When water and oil are mixed together the two ingredients often separate or split. To address this problem, an emulsifier like steareth-20 can be added which helps to produce a stable product.

Is Steareth-20 Safe?

The safety of the steareth ingredients, including steareth-20, has been assessed by the Cosmetic Ingredient Review Expert Panel, a group responsible for evaluating the safety of skincare ingredients. The CIR Expert Panel evaluated the scientific data and concluded that these ingredients were safe as cosmetic ingredients in the present practices of use and concentration. In 2006, as part of the scheduled re-evaluation of ingredients, the CIR Expert Panel considered available new data on the steareth ingredients and reaffirmed the above conclusion.

Despite the approval of steareth-20 by the CIR Expert Panel, there are concerns about the presence of ethylene oxide in this ingredient. This is because the process of ethoxylation may lead to contamination with 1,4-dioxane, a potentially dangerous by-product. In fact, 1,4-dioxane is a known animal carcinogen that penetrates readily into the skin. This ingredient has also been linked with skin allergies. However, manufacturing and purifying processes and guidelines ensure the safety of ingredients that are produced via ethoxylation. 

References:Cosmetic Ingredient Review, 1988. ‘ Final Report on the Safety Assessment of Steareth-2, -4, -6, -7, -10,-11, -13, -15, and -20’, International Journal of Toxicology. 



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