Sometimes dimethicones get a bad rap. They’re part of the silicone family. And, since silicones are synthetically derived, the holistic community will condemn them to the nth degree. But, the truth is, they’re not all bad.
Dimethicones (aka polydimethylsiloxanes) are silicone oils found in everything from mascaras to moisturizers. While they’re mostly known for providing “slip” to skincare (and makeup) products, they also provide occlusive, emollient, and anti-foaming benefits.
Since they’re non-comedogenic (they don’t clog pores) and hypoallergenic (they’re unlikely to cause allergic reactions), dimethicones are an ideal ingredient for sensitive skin types.
A lot of folks out there are convinced that dimethicones will suffocate skin. Well, I’m glad to report that they’re vapor permeable. That’s fancy talk for having a breathable barrier–it allows air (yep, water vapor) to pass through it.
Additionally, dimethicones are excellent hydrators. You see, they’re occlusive agents, meaning they lock-in moisture (and prevent moisture from evaporating). So, they act as a second defense against TEWL (transepidermal water loss).
Oh, and another thing.
Unlike glycerin (another popular occlusive used in moisturizers), dimethicones aren’t greasy. You can rest easy and pack away your blotting papers when using a dimethicone-laden product. Hooray!
Earlier, I mentioned that dimethicones are non-comedogenic. While that’s true (when it’s used on its own), it can become comedogenic when combined with other ingredients like petrolatum and mineral oil. On this note, it’s always important to read the ingredients list on your products to weed out any nasties.
Okay, I’ll admit it. Occlusives have a dark side. They can trap things (like dirt, sweat, and bacteria) underneath their barrier. Ideally, you would apply dimethicone-rich products to a clean face. And, likewise, you should avoid working out while wearing these products–trapped sweat can cause breakouts (no thank you!).
Even though it has hydrating properties, some people still find dimethicones to be drying, especially used over an extended period of time. From the studies I’ve read and from the products I’ve used, I don’t exactly know how this could happen. But, judging by forum posts, it’s a thing and it’s important to mention.
- Polydimethylsiloxane (PDMS)
- Dimethyl silicone
- Mirasil DM 20
- DC 1664
What It’s Used In
You can find dimethicones in pretty much ALL of your skincare and beauty products. Specifically, they can be found in moisturizers (the oil-free kind), lipsticks, mascaras, eyeliners, facial primers, conditioner, leave-in hair products, and even fast foods.
Dimethicones are so widely used because they’re a good alternative to toxic petrolatums and greasy glycerins. When added to products, they provide a slip, making products easily spreadable. But, at the end of the day, they engender a love/hate dynamic–some people think they’re great, while others think they cause breakouts.