Dimethicone is a type of silicone, which comes from heating sand with carbon at high temperatures. Dimethicone is a popular ingredient in many cosmetics, such as skin and hair care products, as it smooths over rough surfaces and has a velvety texture.
Dimethicone also forms a protective barrier on the skin, decreasing the loss of moisture and providing some protection from irritants or allergens.
Experts consider dimethicone to be a safe ingredient with few to no side effects. However, while it is safe for humans, it has a detrimental effect on the environment. Some people prefer to avoid silicones in personal care products for this reason.
This article considers the benefits and risks of using products with dimethicone and suggests alternative products for people who wish to avoid the ingredient.
Dimethicone, also known as polydimethylsiloxane, is a substance that comes from silicone. Silicone comes from silica, which is a natural compound present in sand, sandstone, granite, and quartz.
Manufacturers produce silicone by heating sand with carbon at very high temperatures, up to 2,200°C (3,992°F). As a result, it is hard to classify whether ingredients such as dimethicone are natural or laboratory-made.
Many cosmetics contain dimethicone. It alters the texture of formulas so that they have a silky, velvety feel. It is also odorless, colorless, hypoallergenic, and noncomedogenic, meaning it has a low risk of blocking pores.
People can find dimethicone on the label of many products, including:
- moisturizers
- sunscreens
- fake tanners
- shampoos and conditioners
- detangling products
- head lice removal products
- makeup, such as primers and foundation
- sexual lubricants
Dimethicone also has medical uses. Some medications for flatulence or irritable bowel syndrome may contain simethicone, which is a mix of silica gel and dimethicone. This
Dimethicone has several properties that make it useful for skin and hair products. It:
- Forms a barrier: Dimethicone sits on top of the skin and hair, forming a temporary barrier. This means it provides some protection against contact with irritants or allergens.
- Maintains moisture: By forming a barrier over the skin, dimethicone also reduces the amount of water the skin loses.
- Improves texture: Dimethicone smooths surfaces by filling in crevices. This includes large pores and fine lines. In hair products, dimethicone coats the cuticle of the hair, making it feel smoother. Dimethicone also makes the texture of products more “slippy,” allowing for easier application.
- Gives a matte finish: Primers and moisturizers for oily skin often contain dimethicone because it has a matte finish. Dimethicone also helps to seal in moisture without the need for heavier ingredients, such as oils and butters, which can be comedogenic (can block pores).
Experts widely regard dimethicone as safe for humans.
Dimethicone contains large molecules, which means that it mostly sits on top of the skin or hair. A 2021 safety report confirmed that, in laboratory studies, dimethicone had a low rate of absorption through the skin. Past animal testing also found no evidence of toxicity for dimethicone.
The Food and Drug Administration (FDA) approves dimethicone for use as an active ingredient. This means that a review of data on the product’s effects found that its benefits outweigh any potential risks.
Simethicone is safe for adults to use internally at recommended doses, including when a person is pregnant or breastfeeding. A
Dimethicone has few known side effects or risks. However, there is evidence that it may not be as effective as other ingredients when it comes to hair care.
A 2018 study on untreated hair found that a product containing plant oils had a more beneficial effect on hair strength and shine compared with a silicone-based product. This suggests that while plant oils can actively improve hair health, silicones only have a superficial effect on improving hair texture.
Frequent use of some silicones can also cause a buildup of the substance in a person’s hair. Occasional use of a clarifying shampoo, or switching to silicone-free products, may help with this.
There is little evidence that dimethicone can cause adverse skin reactions. In past animal studies, some animals developed redness where researchers applied dimethicone to the skin. However, this was temporary and resolved quickly when the researchers stopped applying it.
If any product causes the following symptoms, wash it off with a gentle cleanser and stop using it:
- redness or inflammation
- itching
- swelling
- burning or stinging
If symptoms do not ease after a few days, a person should contact their doctor or dermatologist.
Although silicones come from natural sources, the chemical engineering that goes into creating them makes them harmful to the environment.
Silicones sit on the skin and hair rather than sinking in. This means that when someone removes them, they wash down the drain. From here, they enter the water system, and eventually, rivers and oceans.
In small amounts, this does not have a substantial impact. However, the widespread use of silicone-based cosmetics is causing concern among environmental scientists. According to a 2021 report, approximately 4.7 tonnes of certain silicones enter surface water every year in the European Union.
The report states that these emissions largely come from the use of wash-off products. Scientists have found silicones in the blood of fish, birds, and mammals. Some organizations say silicones are toxic to ecosystems and that they bioaccumulate, meaning they build up in the environment without breaking down.
The E.U. has placed limits on the addition of some silicones to products, but not all. The 2021 report calls for closer monitoring on the use of silicones and their release into the environment.
Alternatives to silicone-based products are available. These include silicone-free shampoos, conditioners, and hair styling products. People can look for “silicone free” on the label or read the ingredients list. Ingredients that end in “-cone” or “-siloxane” are likely to be silicones.
It is fairly easy to replace silicones in hair products, as plant oils and butters can also create a barrier around the hair follicle. They can keep moisture in, improve shine, and unlike silicones, strengthen the hair.
In skin care and other products, replacing silicones can be more difficult. There are not many substances that have the same combination of properties as dimethicone. However, there are ingredients that can replicate one or more of its benefits, such as:
- Humectants: Humectants pull moisture to the skin and trap it there, increasing hydration. Glycerin and hyaluronic acid are two natural humectants that help moisturize the skin without the need for oils.
- Colloidal oatmeal: Made from ground oat grains, this emollient can soften and smooth the skin. The FDA approved it as a skin protectant, and a
2020 study found that a 1% colloidal oatmeal eczema cream significantly improved the skin’s pH, barrier function, and hydration. - Squalene: This is a fatty molecule that can come from plants or animals. It moisturizes the skin and helps it retain moisture, but is also lightweight and noncomedogenic, similar to dimethicone.
- Kaolin: This clay
can absorb excess oil from the skin, helping it stay matte throughout the day.
Dimethicone is a type of silicone, which is a substance that comes from heating sand and carbon at high temperatures. In cosmetics and personal care products, dimethicone forms a barrier over the skin or hair, reduces moisture loss, and smooths over bumps and pores.
This ingredient is safe for human use and has a low potential for causing any adverse effects. However, when dimethicone washes into the water system, it can accumulate and cause harm to the environment.
Silicones also may not be the most effective ingredient for strengthening the hair. While they do increase shine, the effect may be superficial. There are silicone-free alternatives available for those who want to avoid these substances.