What Is PEG-10 Dimethicone?
Peg-10 dimethicone is a type of silicone that is used in hair and skincare products as a conditioning agent, lubricant, and skin protectant.
PEG-10 dimethicone is a type of silicone. Silicones are synthetic polymers made up of repeating units of siloxane or elemental silicon and oxygen, which is why silicones may also be referred to as polysiloxanes. Often, the terms ‘silicone’ and ‘silicon’ are mistakenly used interchangeably, when they are actually quite different. Silicon is the 14th element on the periodic table and the second most abundant element in the earth’s crust, after oxygen. In contrast, silicones are always synthetically produced.
Dimethicone, also known as polydimethylsiloxane, is composed of organic carbon-based groups attached to a linear inorganic backbone of silicon and oxygen. The prefix ‘‘dimeth” refers to the two methyl groups that are attached to the silicone molecule to form dimethicone. Based on this structure, dimethicone is considered to be a hydrophobic or oil soluble ingredient. One way to make dimethicone more water-soluble is by a process called ethoxylation.
the good:Helps to improve the texture and feel of skincare and cosmetic formulations. It also has an added benefit of acting as a protective barrier for the skin.
the not so good:There are concerns about the presence of 1,4-dioxane in this ingredient. This is less of a concern more recently as the process of purifying Peg-10 Dimethicone is highly regulated.
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:Nothing to keep an eye on here.
Why Is PEG-10 Dimethicone Used?
As a class, silicones improve the feel, appearance, and performance of products. They act as silky moisturizers, conditioners, solvents, and delivery agents for other ingredients, as well as improve product spreadability.
Upon application to the skin, silicones form a film on the surface while still allowing skin to ‘breathe’. Oxygen, nitrogen, and other nutrients can still pass through the film formed by silicones. However, most silicones do not allow water to pass through, which is an ideal quality for preventing dry, dehydrated skin. Silicones provide an exceptionally desirable skin-feel that is dry and non-greasy, yet silky smooth.
More specifically, PEG-10 dimethicone functions to condition, lubricate, and protect the skin. The combination of silicone with methyl groups tends to make it extremely resistant to water, yet it keeps them flexible and moving free, ideal properties for a lubricant. Due to its large molecular size, PEG-10 dimethicone is not well absorbed into the skin. Therefore, upon application, PEG-10 dimethicone not only prevents water loss, but also protects the skin from penetration of harmful substances, such as irritants and bacteria. Thus, PEG-10 dimethicone can be classified as a skin protectant.
PEG-10 dimethicone is also commonly used in hair care products. The hydrophobic portion of PEG-10 dimethicone works to make hair shiny and slippery, as well as prevents tangles. Furthermore, the water-soluble portion of this ingredient prevents product build-up, which is a common problem for other non-water soluble silicones.
Is PEG-10 Dimethicone Safe?
The Cosmetic Ingredient Review (CIR) Expert Panel, a group responsible for evaluating the safety of skincare and cosmetic ingredients reviewed the safety of 62 dimethicone crosspolymer ingredients, including PEG-10 dimethicone. The Expert Panel concluded that these dimethicone crosspolymer ingredients are safe as used in cosmetics and personal care products.
Despite the approval by the CIR Expert Panel, PEG-10 dimethicone is often called a ‘toxic’ ingredient that should be avoided. One reason PEG-10 dimethicone has received a bad reputation is due to possible contamination with 1,4-dioxane. This is because the process of ethoxylation may lead to contamination with 1,4-dioxane, a potentially dangerous by-product. 1,4-dioxane is a known animal carcinogen that penetrates readily into the skin. According to the National Toxicology Program, ‘1,4-dioxane is reasonably anticipated to be a human carcinogen.’ It has also been linked with skin allergies. However, the potential presence of 1,4-dioxane can be controlled through purification steps to remove it before blending PEG-10 dimethicone into cosmetic formulations.
Additionally, there are claims that silicones as a class can cause or worsen skin concerns, cause sensitization, and “suffocate” skin. However, these claims have not been proven in any published research. The large molecular size of silicones, including PEG-10 dimethicone, prevents them from being absorbed by the skin. If a substance cannot penetrate the skin, it cannot react with cells of the immune system. Thus, silicones, including PEG-10 dimethicone are not considered to be allergens. Silicones are so biologically inert when in contact with the skin, silicones are now replacing latex, a common allergen in adhesives, gloves, and a wide array of other items.
References:Becker, L, 2014. ‘Safety Assessment of Dimethicone Crosspolymers as Used in Cosmetics’, International Journal of Toxicology.