Also known as polymethylsiloxane, dimethicone is actually a silicone-based polymer that is being largely used in the manufacturing of cosmetic products of all types for about 60 years now. Dimethicone belongs to a group of polymeric organosilicon compounds that are usually addressed to as silicones. According to a white paper released by Dow Corning, about half of personal care products released in 2015 contained at least one silicone derivative.
By changing the molecular structure one can literally create endless ingredients with endless properties varying from foaming surfactants to antifoams, shine additives, emollients, emulsifiers, film formers etc.
Silicones are being applied in hair and body care (rinse-off and leave-on), baby care, decorative cosmetics, antiperspirants and sunscreens. They are unique in their light and dry feel, lubricity, slip and shine. Apart from that, there are volatile silicones (cyclomethicones) that are vastly used in hair styling products and in anti-perspirants.
Some suppliers refer to dimethicones as "naturally derived from sand". Sand is no doubt the starting material for making all these silicone derivatives and what could be more "natural" than sand? But sand/quartz is the end of "natural" for silicone. The rest is attaching petrochemical based functional ingredients to the siloxane backbone to create all these -cones we can find on the label of almost every single mainstream personal care product. There are even silicone derivatives where they attach the dimethicone to a "natural" ingredient such as beeswax or plant oils.
Apart from the fact that there are petrochemicals involved in manufacturing dimethicones, even if they are attached to plant oils, they are bioaccumulative and build-up in the environment. Even though the pro-silicone front is persistently claiming silicones do not bioaccumulate and would biodegrade after how many million years?
The covering and trapping property of dimethicone means that it's not just trapping moisture, but bacteria, skin oils, sebum, and other impurities. That means those prone to acne or with oily skin are more likely to see increased blackheads and breakouts when using products containing this ingredient.
In some countries, warnings have been raised concerning the substance’s use in pregnant women or in women who were breastfeeding. Physicians recommend avoiding the use of dimethicone-based cosmetics, at least in large quantities.
Skin specialists suggest that patients who suffer from certain skin conditions, such as rosacea, should check with their physicians first before actually using any cosmetic and OTC drug products with a high dimethicone content.
What are the side effects of dimethicone?
- Itching of skin
- Redness of skin (rare)
- Hair loss (rare)
Therefore, cosmetic and OTC drug products containing dimethicones are not "natural" and should not be labeled as "natural" products.