Recently, I read an article on FutureDerm and replied to a few comments asking about the idea of how silicones trap active ingredients, preventing them from reaching the skin. Here’s a breakdown of what happened:
Nicki of FutureDerm fame stated:
“While beneficial skin care ingredients can have some documented effects in cosmetics with a silicone base, the effects will not be as profound as if the ingredients were in creams or serums with other delivery systems. This makes sense, but I was never sure until I read reports micronized zinc oxide cannot penetrate the skin if it is presented in creams with silicones (Dermatologic Therapy, 2007). If micronized zinc oxide cannot penetrate the skin, then I wouldn’t imagine many other cosmetics ingredients embedded in silicones could either.”
Then two readers, Nicholas and Erin, asked the following two questions, respectively:
- Speaking of the antioxidants embedded in silicones, have you reviewed any of the Paula’s Choice Serums? I’m using the Resist Antioxidant Serum and I’d like to know your opinion on that one. Thanks!
- Just a question… you were mentioning that skin care ingredients like micronised zinc wouldn’t penetrate the skin well if it were in a silicone base. What would happen then if I were to use a silicone based antioxidant serum, then top it off with a moisturizer and a zinc oxide or chemical sunblock? Would the initial silicone serum prevent the moisturizer and sunblock from exerting its effects as well?
I proceeded to answer their questions with my own slightly logical (or illogical) musings:
“You know, when Nicki mentioned this idea of silicone “entraption,” I kind of stopped and wondered, “Hm, maybe that has some merit to it.”
From personal experience I’ve definitely seen improvement in my skin from silicone-based serums, like the Paula’s Choice RESIST one Nick mentioned. However, without proper examination tools, I can’t histologically attribute these improvements to specific ingredients, because I can’t witness the exact interaction mechanism. Perhaps my skin’s improvement was just from being more moisturized, or maybe it’s something completely else, like glycolic and salicylic acid.
But here’s some food for thought, and I’d love to see some real documentation about this intriguing topic. Maybe I’ll do some research myself and write a follow-up post… We’ll see. xD
Now, many prescription medical products employ silicone-derived vehicular bases as delivery systems for topical drugs. So that at least, gives some weight to the fact that silicone-based products are not completely ineffective. Obviously, a water-based serum with chemical penetration enhancers would be (on a case by case basis) preferred.
As for the “micronized” zinc oxide not being able to penetrate into the skin, concept… try to think of it in another one. Silicone is used a suspending agent; basically it holds all the other ingredients in place. So if you think of the silicone molecules as people, collectively holding up a heavy object such as epigallocatechin gallate (EGCG), the smaller the object, the easier (or less strength) is required to hold it up. So something as small as micronized zinc oxide would be very easy to hold, since it’s so small.
So something like EGCG or a lipid-soluble palmitic-acid based vitamin C derivative, such as ascorbyl tetraisopalmitate AKA tetrahexyldecyl ascorbate, would require a LOT of additional “strength” to hold up, or to prevent from penetrating the skin. So naturally, these much larger molecules would slowly “fall” through the silicone suspension, eventually reaching the skin. Think of it passive transport through a semi-permeable membrane, or something.
But again, this is a very general, simplistic, and slightly over-reaching analogy, but just think about it. It does make (a little) sense. So yeah, I hope that puts some of your minds to ease. If you’ve been using silicone-based serums, know that it wasn’t ALL in vain.