Due to their occlusive nature, silicones are among the most misunderstood ingredients used in skincare. Many people believe that because these ingredients can create a barrier on the skin, they must suffocate it, cause breakouts and just exacerbate the signs of aging. However, these are just myths. No study has ever found the remotest proof to support any of these claims.
Instead, this barrier may pose another concern: it may prevent some of the ingredients in your moisturizers from doing their job properly. I say may because studies on the subject are seriously lacking, so we’ll have to supply those with logic and common sense. They’re not always as reliable, but hopefully we will still be able to get a better understanding of how silicones work. But first:
What are silicones and why are they used in skincare products?
Silicones, such as Dimethicone, Cyclopentasiloxane and Phenyl Trimethicone, are derived from silica. They are used in skincare products for several reasons: they give slip to a product, allowing it to spread easily on the skin; they make skin feel silky soft and smooth to the tocuh; they help minimize the appearance of fine lines and wrinkles by temporarily filling them in; they create a barrier on the skin that binds water in and protects it from irritation. Their particular molecule structure, which is made of larger molecules with wider spaces between each molecule, allows them to create a barrier that’s both protective and breathable.
Are silicone-based delivery systems effective?
The particular structure of this barrier raises the question of whether the active ingredients in skincare products with silicones will be able to penetrate through it or if they’ll stay on the surface. So, what’s the answer? I’d love to give it to you but unfortunately there isn’t a definite one. It doesn’t look like any studies on the topic have been done (at least I couldn’t found any, but if you can, please let me know), but with a bit of help from the experts, we can try to hazard a hypothesis of what happens.
Paula Begoun believes that silicones allow active ingredients to penetrate the skin and says we should 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.”
That’s reassuring and makes sense. After all, there are a lot of prescription medical products that employ silicone-based delivery systems for topical drugs, and if silicones prevented the active ingredients in them from penetrating the skin, these would be completely useless. Instead, they work quite well. It would be interesting to see a study comparing the efficacy of different types of delivery systems and see how well the silicone-based one fares, but even if there were better methods to deliver ingredients into the skin, that wouldn’t make this one totally ineffective.
What about the products you’re gonna apply next?
However, so far this information seems to confirm only that the active ingredients suspended in a silicone base manage to get through and do their job. But most of us don’t just use one skincare product. We may use a moisturizer, a serum, maybe a prescription product. And what happens if we apply first the one that’s loaded with, let’s say, Dimethicone? The ingredients in that product will sink into the skin, but will those in the products you’re gonna apply next get through too?
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 further adds that the efficacy of this barrier at keeping things out of the skin 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.” Of course “may well block” is not the same thing as “will block”, but it does make sense that active ingredients will find it harder to sink into the skin when applied on top of a barrier. Some of them may still be able to penetrate it to a certain extent, but until we know for sure, I think it would be better to apply products with a high concentration of silicones last.
The bottom line
Silicones form a barrier on the skin that’s breathable and yet prevents water loss. However, whether they also prevent active ingredients from penetrating into the skin is unknown. While silicones act as an effective delivery system to get actives into the skin, they may prevent the ingredients in whatever products you’re applying next to sink in properly, compromising their efficacy. At the moment, this is only a theory, but until we know more I believe it’s best to apply products with a high concentrations of silicones last.
Do you use products with silicones? Do you think they can prevent other ingredients from doing their job properly?