silicones prevent active ingredients from penetrating skin

Question: what happens when you use a serum with silicones followed by a moisturiser?

A. Your moisturiser become useless. It can’t penetrate the barrier silicones leave on your skin.

B. Your moisturiser is a smart cookie and easily penetrates through everything. Silicones are no match for it.

C. Your moisturiser slips through the cracks silicones leave behind. That barrier isn’t that impenetrable after all.

If you’ve answered A, you’re in good company. I’ve lost count of how many people think silicones create an impenetrable barrier on the skin that suffocates it and prevents anything else you apply afterwards from penetrating it.

But that’s not really what’s going on. Turns out, silicones aren’t that impenetrable after all…

What Are Silicones And Why Are They In Your Skincare Products?

First things first. Silicones are a group of ingredients derived from silica. The most famous are dimethicone, cyclomethicone and phenyl trimethicone. Basically, if it ends in -cone, it’s likely a silicone.

They’re used in skincare products for several reasons:

  • They give slip to a product, so that it spreads easily on your skin.
  • They make skin silky soft and smooth to the touch.
  • They fill in fine lines and wrinkles, making them look smaller (the effect is temporary).
  • They create a barrier on the skin that binds water in.

That last one is the reason why silicones get a lot of hate. The word barrier conjures images of sky-high walls of reinforced concrete. What can get through that?

That’s not what silicones make. Silicones have a particular molecule structure that’s made of larger molecules with wider spaces between each molecule.

Think of it more as a net. This barrier is both protective and breathable.

Related: Are Silicones Bad For Skin?

Want to know the bad ingredients you absolutely need to avoid in your skincare products? Download the “Skincare Ingredients To Avoid” cheat sheet to find out (hint: they’re not what you think):

Can Silicones Deliver Ingredients Through The Skin?

Now you know this barrier looks more like a net than a concrete wall, let’s take a look at what happens when you use products with both silicones AND active ingredients.

If you’re using, let’s say, a serum with retinol and dimethicone, you want retinol to bypass dimethicone and get through into your skin. Is this possible or will dimethicone stand in its way?

My fave skincare guru Paula Begoun believes that silicones do allow active ingredients to penetrate your skin. She says to think of them as tea bags:

“When you steep the tea bag in water the tea and all of its antioxidant properties are released. Silicones remain on the surface of your skin and the other ingredients it is mixed with ‘steep’ through. All ingredients have to be suspended in some base formula. Some of those ingredients remain on the surface, some absorb. Either way the “actives” get through.”

Not convinced? Think of all the medicines that use silicone-based delivery systems. If silicones prevented the active ingredients in drugs to penetrate your skin, those medicines wouldn’t work. But they do.

Related: The Complete Guide To Retinol: What It Is, What It Does, And How To Use It

Do Silicone Prevent Whatever Product You Apply Next From Penetrating Your Skin?

If a product has both silicones and active ingredients, the actives get through. But, what if you layer them on top of each other?

Let’s say you use a serum with silicones and then follow up with a moisturiser. Will the actives in your moisturiser be able to get through silicones now they’ve settled onto your skin?

The Beauty Brains, in a response to a reader asking why her hair dye doesn’t stain her skin when she applies a cream with silicones beforehand, hazard an educated guess:

“When you apply a cream containing “goodies” along with silicones, the cream hits the face all at once, the ingredients that will penetrate have time to sink into the skin before all the water evaporates and the silicones set up an occlusive film. When you apply a silicone cream FIRST and then sometime later apply another product (like a hair color) the silicones have had time to set up as a film and so they do a better job of keeping stuff OUT of the skin. Hence, no staining.”

Dermatologist Cynthia Bailey adds that the efficacy of this barrier depends on the concentration of silicones: “It depends on how much dimethicone is in the product, though. Products with a large amount of dimethicone could well block tretinoin if they are applied first.”

FYI, not all silicones are created equal. A high dose of dimethicone may make it harder for retinol to get through, but other silicones (like cyclomethicone) are more volatile and evaporate from your skin quickly.

As always, there’s not really a clear cut answer. It depends on what silicones are in your products and in what amount. But, if that worries you, just apply your actives first. Problem solved.

The Bottom Line

Silicones form a barrier on the skin that’s breathable and yet prevents water loss. They don’t prevent the actives that are in the same products as them from penetrating your skin. But, anything you apply afterward may indeed struggle to get through. If your skincare product is loaded with dimethicone, you may want to apply it last.