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Silicones in serums
Hello All,
Sorry if it sounds like a not very educated question. Would silicones in a serum compromise absorption of active ingredients from a moisturiser applied on the top of the serum? I had an assumption that only very last product that is being applied to the skin should contain silicones, but recently I found a serum, that seems pretty well formulated, and it contains PEG-8 Dimethicone. My assumption is coming from the idea that products should be applied in order: from the lighter texture to heavier texture (essence, water-based serum, moisturiser etc.) and since silicones reduce TDWL they might reduce absorption of active ingredients from the next product. I understand that silicones don’t form a “film” on the skin but still sounds a bit counterintuitive to me. I would really appreciate an opinion of professionals.
Thanks in advance.
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18 Replies
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Repeat after me….”Cosmetics do not significantly penetrate the skin.” As such, this is really not even fairly a secondary issue and one I would not get concerned with. There are so many other overall issues to a successful Formulation.
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No. Silicones won’t interfere with absorption in any significant way because as @Microformulation says, active ingredients don’t really penetrate significantly anyway.
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@ngarayeva001 I do want to stress not to get discouraged or feel as if you are being attacked. It is very common for novices to enter into Formulation while still believing a great deal of the crap out there. Be skeptical. Use the Scientific method. Set standards for sources of information. In the end, you will learn.Much of what you are bringing to the table is that misinformation. Generally, it is marketing crap. I may be naive, but I still believe that I can make a quality Cosmetic product that promises credible Cosmetic claims, this product can be ethically marketed and be successful.Keep learning.
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Isn’t the skin a wonderful organ? Be thankful that only very, very few substances have the ability to be absorbed transdermally!
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Thank you @Microformulation. Don’t worry I absolutely don’t feel attacked, and I appreciate your answers a lot!. Just one question. I understand that all these algae extracts and not so well researched peptides are marketing claims. But what about researched ingredients, such as LAA (and some of its derivatives), Niacinamide, Retinol? Salicylic acid at the end of the day. It works in pores, so it “penetrates”? Probably I am missing something but I listened to most (if not all) of @Perry ‘s podcasts before I formed my opinion (additionally to reading research papers, most of which I started questioning now). And I came to the conclusion that above-mentioned ingredients should work. I am probably missing something.
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Yes, but first you are missing a minor point. Salicylic acid, when used on the pores, is that a Cosmetic Product? No, when used at effective levels is an OTC DRUG.There are several Cosmetic actives that have some activity that would be purported drug claims such as Niacinamide and Retinol.The vast and overwhelming majority of actives and products do not absorb significantly. That is the Science. The concern, the chemophobia and all the memes “80% of what you put on your skin is absorbed” is marketing driven pseudoscience.If you truly want to increase penetration of products, you would need to transition to OTC or Pharmaceutical products. It is irresponsible, dangerous and often not technically feasible in Cosmetics.
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Ok, I understand the point now. Thank you for clarification @Microformulation
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@Microformulation, I was thinking about your comment and I have one question. Hope you don’t mind answering. In case if we are dealing with the effective levels of researched ingredients which makes it OTC drug (disclaimer, I am not doing it. I am afraid even approaching retinol at this stage), would the addition of silicones to such product decrease its efficacy (I am not using word penetration!)? To make my question more precise, let’s say that silicone is dimethicone 500 and the active ingredient is 10% of niacinamide. Thank you.
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@ngarayeva001 Let me challenge you with a few other questions that may direct you to your own answer. I am sorry if it becomes pedantic.Dimethicone 500cst is beginning to approach the more viscous grades and is in general used in skin protectants to create a barrier. I have used it in scar treatment products etc. Why would you create a product with a known barrier and add an active? Of course, theoretically it would increase the absorption, but why?Let’s say that you proposed a different active and designed a product with a Dimethicone barrier to increase absorption. Is this something that you should be doing? You could increase irritation and the increase of absorption minimally. We could go back and forth, but I will say categorically that this is not an area we should explore, that being seeking a substantial skin penetration, without a great deal more technical support and I would wager a lot more letters after our names.So, playing devil’s advocate. I submit that the dimethicone would likely increase the absorption due to the barrier it produces (much like the technical grade membranes we used in trans dermal patches but in a very crude form) and the increase in contact time due to the persistence of the dimethicone on the skin. Lets say that you decide to capitalize on this effect to increase absorption of an active. Propose to me a Cosmetic product and active where you feel that the increase in absorption is warranted or where it would be safe and responsible. Remember that you pretty quickly will tip to an OTC product if there is any significant absorption and we have ruled this out due to lack of technical support and monitored study protocols.It is not impossible, but the effect is finite. I will propose one, sunless tanners and the use of DMI to increase the penetration of Dihydroxyacetone (DHA) into the upper levels of the skin. It is the very upper layers of the skin and finite. It is more in order to get a more consistent effect.Don’t cite Salicylic acid in Acne care, we ruled out OTC.
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@Microformulation thank you very much for your detailed answer. I understand your point. The main way of learning for me is analyzing ingredients lists of sucessful commercial products. One of examples where I noticed an attempt to increase penetration (not by using silicones but DMI) is Niacinamide serum made by The Ordinary. It contains 10% of Niacinamide, sodium hyaluronate, DMI and polyacrylate crosspolimer 6, (the remaining ingredients are below 1% I believe). They also added DMI to 2% salicylic acid formula (pH is 6, so it isn’t a peeling) and a couple of others. Regarding silicones I saw PEG-8 in Paula’s choice peptides booster. I understand that peptides don’t do much and PEG-8 in that case is a texture enhancer. But what is about pairing 10% of Niacinamide with DMI? Maybe I understood it wrong and DMI has some other function in that formula?
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First, we are going to keep batting Niacinamide around. 10% is far too high. Look at these two resources and then let us never speak of Niacinamide again. You will see 10% is a waste.The DMI is being used with the Niacinamide, but again they are not making any drug claims and “maybe” it helps. Again, I submit that a great Formulation uses multiple actives and modalities to deliver the claims. Shotgunning one ingredient can be one-dimensional in regards to performance.With the Salicylic acid products, they are again not making any drug claims when used as an exfoliant, at least any that make it fall under an OTC monograph. It can assist the product, but not cross the line.You also keep mentioning the PEG-8 Dimethicone. I am unsure of your knowledge level, but let me ask you a leading question that may either stump you, cause you to do some credible reading on the topic or be elementary to you. Why do we create PEG’s and what benefit do we gain? As a hint, I also ask why you might see an ingredient such as PEG-75 Lanolin? What do we gain? What is the outdated market bias against PEG’s and what is the concern with PEG’s under some natural standards?
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@Microformulation thank you for links. They confirmed what I read in another source (6% is the maximum for Niacinamide). I absolutely agree that skin needs more than one ingredient. Regarding PEG-8, I just explained where my questions are coming from (analyzing ingredients and trying to understand the purpose of adding them to a particular product). I am not a chemist as I mentioned before, but what I understand is that concern with PEGs is that they are penetration enhancers and can have impurities (I use water soluble shea butter and PEG emulsifiers and don’t share chemophobia). Again would like to emphasize that I appreciate your detailed answers.
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The concentration of 1,4-dioxane present in most of PEGs is really low. 2-5ppm, being 30 the max allowed. Considering the % of PEG you will use in a formula the amount of impurities is hardly a concern, how much could penetrate?. But fear beats logic every time.
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PEGs is that they are penetration enhancers and can have impuritiesKind of for the second part. I don’t believe that PEG’s are penetration enhancers, especially since you are describing a large group of products not a single compound.In the simplest of terms, when you ethoxylate a compound, you can create a PEG. This compound which previously was hydrophobic is now hydrophilic (water soluble). You are doing this with the water-soluble Shea Butter. This allows you to get some of the benefits in an aqueous base.As @DAS points out, one of the by-products of the ethoxylation process is 1,4 dioxane. Since identifying the concerns with these compounds, the suppliers have greatly reduced the percentage of 1,4 dioxane. It is in the very low PPM.Now, even though the Science is sketchy, the market doesn’t care. One of the common misconceptions in the “natural” market is that the presence of a material, regardless of how infinitesimal the concentration is, it is bad. They do not recognize the fact that it is often dose-dependent.
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They do not recognize the fact that it is often dose-dependent.because that requires the use of basic mathematics, which in the anglosphere is either viewed as a terrifying black art bordering on witchcraft, or as literal-minded donkey-work that the truly intellectual shouldn’t have to lumber themselves with -
@Bill_Toge I think it is driven by the same ‘fast thinking’ system that makes people overestimate the risk of flying. People think that risk of getting cancer from parabens/PEGs/silicones is higher than risk of getting poisoned by cyanide in apricot seeds (some even believe it’s extract has health benefits). Also, polyethylene sounds like a plastic bag and silicone sounds like a ‘rubber’ used to seal shower.
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@Bill_Toge “literal-minded donkey-work..” I now have a better job description for my resume.
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Microformulation said:@ngarayeva001 Let me challenge you with a few other questions that may direct you to your own answer. I am sorry if it becomes pedantic.Dimethicone 500cst is beginning to approach the more viscous grades and is in general used in skin protectants to create a barrier. I have used it in scar treatment products etc. Why would you create a product with a known barrier and add an active? Of course, theoretically it would increase the absorption, but why?Let’s say that you proposed a different active and designed a product with a Dimethicone barrier to increase absorption. Is this something that you should be doing? You could increase irritation and the increase of absorption minimally. We could go back and forth, but I will say categorically that this is not an area we should explore, that being seeking a substantial skin penetration, without a great deal more technical support and I would wager a lot more letters after our names.So, playing devil’s advocate. I submit that the dimethicone would likely increase the absorption due to the barrier it produces (much like the technical grade membranes we used in trans dermal patches but in a very crude form) and the increase in contact time due to the persistence of the dimethicone on the skin. Lets say that you decide to capitalize on this effect to increase absorption of an active. Propose to me a Cosmetic product and active where you feel that the increase in absorption is warranted or where it would be safe and responsible. Remember that you pretty quickly will tip to an OTC product if there is any significant absorption and we have ruled this out due to lack of technical support and monitored study protocols.It is not impossible, but the effect is finite. I will propose one, sunless tanners and the use of DMI to increase the penetration of Dihydroxyacetone (DHA) into the upper levels of the skin. It is the very upper layers of the skin and finite. It is more in order to get a more consistent effect.Don’t cite Salicylic acid in Acne care, we ruled out OTC.
@microfor@Microformulation does ingredients that create a barrier like dimethicone and petrolatum increase the absorption of other ingredients?
If yes then why and how?
Isn’t The function of barrier to prevent or reduce the entering of substances?
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