Article by: Perry Romanowski

When you are meeting with a cosmetic raw material supplier, they often talk about how their ingredient will penetrate the skin.  Even cosmetic marketers use the phrase “skin penetration” when advertising skin and anti-aging products. Penetration seems to be an important characteristic of cosmetics but have you ever thought about why anyone would want a cosmetic ingredient to “penetrate”?

What is skin penetration?

The term penetration is used to describe a characteristic of cosmetic ingredients in which they migrate from the surface of skin into the lower layers of the skin cells. Our skin is made up of a number of cell layers and some ingredients can penetrate deep into those layers. If you want your product to go below the surface of skin you want something that penetrates.

Why skin penetration

While many people tout penetration as a benefit there are only certain times you want your formulation to penetrate the skin. This would include situations in which you want to improve the feel of the formula upon application and when you want to make water resistant claims.

However, these are not the reason that most marketers (and some cosmetic chemists) desire skin penetration. Many people want their products to penetrate the skin to improve the effectiveness of the “active ingredient”. You see, there are a number of cosmetic ingredients and products that claim to interact with skin cell metabolism, increasing collagen production, or stimulating some other enzyme that will magically remove wrinkles. But the truth is if these ingredients actually could do this, the products would then be considered drugs and would require much more stringent & expensive testing (at least in the United States).
In the US any product that affects skin metabolism is a drug

Penetration enhancers

Although most penetration claims are for non-cosmetic purposes, there are still legitimate reasons that you would want your formulation to penetrate the skin. And for these, it is useful to use penetration enhancer ingredients.

Typical skin penetration ingredients include emulsifiers and solvents. Emulsifiers are surfactants that have both a hydrophobic segment and a hydrophilic segment on the molecule. They allow for compatibility between polar and non-polar ingredients. In a solution, they form micelles which can surround and encapsulate “active” ingredients. When place on the skin, the emulsifiers will penetrate deeper into the skin and bring whatever is encased in the micelle with it. Emulsion penetration can be enhanced by reducing the particle size of the emulsion. So, microemulsions and nanoemulsions are excellent skin penetrating vehicles. Phosphatidylcholine is a good penetration ingredient.

Solvents like propylene glycol are also excellent penetration enhancers. They can help shuttle soluble ingredients through the lipid top layers of the skin into the lower layers.

Penetration enhancing caution

There are times when you do not want your cosmetic to penetrate. This would include products that are cleansers as they can lead to irritation and colors because you want to be able to remove them. Also, cosmetics are designed to make superficial improvements so you also don’t want your product to penetrate down as far as the dermis where the living skin cells are. Once an ingredient gets to the dermis it could interact with skin cells and affect skin metabolism. And while this is what some marketers want to claim about their products, this is not something that you want to actually have happen.


  1. Avatar

    Hi Perry,

    Thanks for all the good info!

    Im making aloe vera gel from leafs and blending/mixing it with pure niaciamide powder and ascorbic acid powder for face skin use. My intention is that the niaciamide and ascorbic acid penetrate the skin barrier as deep as posible. My questions are, since niaciamide and ascorbic acid are water soluble, wich oil would you use as a carrier? Would jojoba oil be a good one? My intention is to use as little carrier oil as posible. What ratio oil/aloe gel do you think will be sufficient? Should i use a water in oil emulsifier? Wich one do you think will help de active ingredients penetrate more? I really aprecciate your imput/guindance.


    Best Regards.

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    Hi Perry: My name is Karen. I’m trying to find a safe ingredient to mix with iodine other than recommended DMSO for treatment of a condition called Dupuytrens Disease. DMSO is supposedly to increase the absorption of the iodine into the fibroids and nodules that cause this disease. Could you recommend something safe that would help increase the absorption of the iodine? Thank you so much.

    1. Avatar
      Perry Romanowski

      Sorry, my expertise is in cosmetic products not in drug actives. You might post your question in our forum to see if someone there has more advice for you.

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    Hey everyone, do you guys know a molecule what should penetrate Skin, but does not penetrate at all or really bad? I look for a negative control for my experiments. (No sun blocker)

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    Joann Fino

    Hi there Perry!
    Perry, im planning to fill 75mg round twist up lotion sticks with formulations for face and body. Some of the oils will include Rosehip, African Immortelle, Rose Geranium, Marula………
    Preservatives, Olivem 1000 and 2020 and so forth. The thing is that i live in a very warm part of South Africa at the Coast. This means that the only way to keep my sticks from melting is to increase the Beeswax in the formula? Is this going to prevent the good stuff in the other oils to serve their intended purpose for the customers skin?
    Best Regards

    1. Avatar
      Perry Romanowski

      Increasing beeswax will not impede the effectiveness of other ingredients.

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    Hi Perry, awesome blog/ website, thank you.

    I have been searching high and low to understand what actually happens when NON-nano Zinc Oxide is mixed with natural oils such as olive oil, coconut oil, sweet almond oil (Also beeswax) in terms of skin penetration and in context of it being a sun protection barrier
    As I understand, zinc oxide sits on-top of the skin as a barrier. Oils will.. Penetrate the skin?

    Question:When the oils are heated and the zinc oxide is mixed in, does this whole mixture penetrate/ permeate into the skin?
    Does zinc still act as a barrier and the oil still penetrate or do they become one and sit on top of the skin with each one having their on SPF.

    All the best and thank you in advance.

    1. Avatar
      Perry Romanowski

      Yes, Zinc Oxide still works when mixed with oils.

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    Do you know what is in Qusome and how to get it? Also for Proprietary Biophere.

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    What do you think of Hyaluronic acid or almond seed oil? It is said the smaller the molecule the better it penetrates the skin

    1. Avatar
      Perry Romanowski

      What are you looking for the ingredients to do? Hyaluronic acid is a humectant so you can expect some moisturization. Almond seed oil is an emollient so it might make skin feel better.

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    I have heard a lot of mixed thoughts on dimethicone/silicones in skin care, but not much talk about whether or not dimethicone can actually prevent skin care ingredients from penetrating. Do you think dimethicone can pose an issue to the efficacy or even block the penetration of ‘active’ skin care ingredients?

    1. Avatar
      Perry Romanowski

      There isn’t much research on this subject. It likely would not block ingredients any more than something like Petrolatum which is found in a lot of skin lotions and sunscreens. Most ‘active’ skin care ingredients are just marketing gimmicks so you wouldn’t really be able to tell a difference in performance whether dimethicone was in the formula or not.

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    Larry Sherrod

    What is your opinion of the penetration capabilities of beeswax and does it contain any vitamins? Is it a barrier as is claimed?

    1. Avatar
      Perry Romanowski

      I don’t think it penetrates to any significant level. Whether it contains vitamins or not doesn’t matter. Topically applied vitamins rarely have an effect. It can be a barrier to certain materials.

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    This post is fantastic!

    Question: I know prescription retinoids penetrate the skin and increase collagen production, but it sounds like OTC retinol must not? So does this mean that OTC retinol isn’t effective for the same things retinoids are? (namely, collagen production, reduction of fine lines, etc) Thanks!

    1. Avatar
      Perry Romanowski

      If something is OTC then it is proven to work.

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        Hi Perry! I have to disagree with your statement that if something is OTC then it’s proven to work. That’s just not accurate. No U.S. agency including the FDA predetermines if a product works before it’s available for public use.

        The FDA may collect samples and inspect facilities but they do not do so to “predetermine” product statement accuracy or safety. The FD&C Act is very specific in that it does not require the FDA or any agency to pre-approve products before they go to market.

        The FDA does however get involved when consumer complaints are filed or for example the FDA determines via product sample or facility spot check that an OTC product is a drug, is misbranded or is adulterated. I’m always surprised when I read FDA warning letters issued to the biggest names in the cosmetic industry for stepping outside the bounds that are so clearly defined by the FD&C Act and the FDA.

        If you have a link to an FDA/FD&C web page that states all OTC products work exactly as stated on packaging and labels, I would appreciate the link so I can update my research database.

        This link is a good overview for anyone who wants to read it of the FDA role in cosmetics and info on the FD&C Act: . The FDA Small Business guide is full of good info as well. In this guide, misconceptions about “natural” products and “organic” are corrected, the former is not recognized by the FDA:

        I enjoy your site Perry. Keep up the good work.

        Best Regards,

    2. Avatar

      The OTC retinol will work, it just takes a lot longer to see results.

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    Hi Perry,

    What gives products like Eucerin lotion that great light texture? Is there a key ingreient?

    Also I just stumbled across this blog post but do you have any recommendations for companies who help formulate manufacture and distribute cosmetic lines for start ups?

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    Brooklynn Baker

    Why are pregnant women warned to stay away from certain ingredients, such as lactic acid and retinol… if it doesn’t penetrate to the blood stream?

    1. Avatar
      Perry Romanowski

      I don’t know. Perhaps a doctor could tell you

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    Hi! I like your article, although it did dissapoint me when I think about all the money I spent on skin care products. My question is..I read in another article that hyaluronic acid can actually penetrate skin because it has small enough molecules, therefore effective as far as aesthetic reasons. Is this true? If so, what are other examples that are small enough to penetrate skin?

    1. Avatar
      Perry Romanowski

      There is some evidence that HA can penetrate skin but it is not because the molecule is small. It may have more to do with its non-polar structure. I’m a bit skeptical that it can penetrate though.

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    Jodie Dodd

    I found your article and comments very interesting. It has brought up a few questions.

    Could you please explain then, the difference between serums and moisturizers? My understanding is that the molecular size allows a serum to penetrate to the living layer of skin and that the moisturizer really only serves to protect and uphold your protective barrier layer buy locking in moisture.

    I come across many people that believe nowadays that simply by putting coconut oil, olive oil, avocado oil, or argan oil is enough to combat age and provide the function of both moisturizer, protectant, and or serum. Your thoughts?

    From an Oncology aesthetician standpoint to you believe then that products with glycol are completely safe to use as they would never penetrate to a layer of skin that could actually cause damage?

    Also, in your opinion is there any 100% natural product that is effective in treating oily acneic skin? My belief is that there is not, as acne skin needs a water based product line, and I have yet to find any that have a all natural stabilizer. I am of the opinion that all natural is not realistic unless you are making it up at home and using it up right away. What are your thoughts?

    1. Avatar
      Perry Romanowski

      The terms “serum” and “moisturizer” are simply marketing terms that don’t really have any scientific meaning. Molecular size has nothing to do with the terms. In the cosmetic industry “serum” just means a clear, slightly thickened liquid. A “moisturizer” is typically an opaque cream. Functionally, their differences depend on the ingredients in the formula. There are serums that moisturize and moisturizers that penetrate deeper into the skin.

      The oils you mentioned provide an emollient effect but they aren’t having any significant anti-aging effect.

      Yes, products with glycol are safe. There is no evidence they substantially damage skin.

      No, there in no effective 100% natural product that clears up acneic skin.

    2. Avatar

      try black seed oil

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    Steven areia

    Is dimethicone bad for the skin

    1. Avatar
      Perry Romanowski


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    Thanks for the article Perry.

    I would think that a dermal delivery topical that actually delivered into the blood stream and CNS would only be considered a drug if the active ingredient is a drug, not a supplement. Can you please point me to any legal literature supporting the claim?

    Thanks in advance!

    1. Avatar
      Perry Romanowski

      If an ingredient penetrates the skin, gets in the bloodstream and has an impact on body metabolism it is by FDA definition a drug. Check the FDA website.

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    Hi, I found your article very interesting!
    I am currently working on making my own cosmetics with natural preservatives like vitamin E.
    I would like to ask you if you know if it is possible to make a cream myself with Phosphatidylcholine. I can order capsules from ebay, but I am not sure those are what I should add to my creams. Can you please advise on this? Also, if i would like to preserve the creams do you have a good suggestion or is vitamin E ok?

    I hope you find time to answer my questions.

    Best regards

    1. Avatar
      Perry Romanowski

      No phosphatidylcholine is not an adequate enough emulsifier to make a cream. No vitamin E is not an adequate preservative for cosmetics.

      1. Avatar

        Then what is an adequate, natural preservative? Ferments such as radish root? Leucidal Liquid SF? If neither of those meet your standards either, please share what you recommend.

        1. Avatar
          Perry Romanowski

          That really depends on what is in your formula and what you consider natural. Radish root is not an adequate preservative for most anything. Leucidial is a decent secondary preservative but will not work because it is not broad spectrum enough. Check our forum for natural preservative suggestions. Typically, an organic acid or phenoxyethanol but it depends on your system.

    2. Avatar
      Brigitte Devenish

      Hi Mai, I make creams and balms and am using vitamin E and rosemary extract as natural preservatives, which seems to work well. I tend to keep a large jar in the fridge (sometimes for months) and a small jar in the bathroom.
      I hope this helps, Brigitte

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    We, Science & Technology Laboratory Co., Ltd are a importer and distributor of skin measuring machine. And, we are very interested in measuring of the absorption and penetration rate of the skin with cosmetic.

    While we have been searching newly invented measuring machine for this task, the absorption and penetration rate, we read your artle. So, we think you know what machine is suitable for the measurement of this task or you have used for your project.

    If you have any information for the measuring machine of absorption and penetration rate of the skin, please introduce to us for Korean cosmetic and raw material manufacturers.

    Thank you and Sincerely,

    1. Avatar
      Perry Romanowski

      I’m not sure I understand your question. But you can contact me directly using the ‘contact us’ button at the top.

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    I have a question regarding makeup penetrating of the skin. I searched the internet for a long time for “save cosmetics” during pregnancy but I have found none. So I bought my own mineral makeup components and made it my self (Titanium dioxide non nano, zinc oxide non nano and iron oxides brown, yellow and red). I mix the mineral makeup with almond oil to apply to the skin. Before the makeup I apply beeswax with coconut oil to protect my skin.
    Do you think that the makeup can penetrate my skin and do harm during pregnancy? I am worrying sick about this, since I want to avoid that it would do harm to the baby during my pregnancy… Thank you for your help…

    1. Avatar
      Perry Romanowski

      Hopefully this will calm your concerns. You do not have to worry about makeup penetrating skin and causing any harm. Makeup (standard products you can buy in the store and your own) is perfectly safe and not something you need to worry about.

      1. Avatar
        Thelma Sansome

        Is it possible the sunscreen with SPF can be mixed with oils like almond and etc. I thought the oils would break down the benefits of the sun protection.

        1. Avatar
          Perry Romanowski

          Sunscreen effectiveness depends a lot on how the products are made so yes, it can have an effect.

  20. Avatar

    Hi Perry,

    I would like to learn why you ended this article with this sentence:

    “Once an ingredient gets to the dermis it could interact with skin cells and affect skin metabolism. And while this is what some marketers want to claim about their products, this is not something that you want to actually have happen.”

    Why we may not want them to interact with our skin cells in dermis? Is it dangerous? I thought it is a good thing because once they interact with the skin cells in dermis they can stimulate the collagen production which is a good thing, right?



    1. Avatar
      Perry Romanowski

      If a product interacts with the cells in the dermis it is no longer a cosmetic, it is a drug. And drugs face different regulations than cosmetics. Yes, it could be dangerous.

  21. Avatar
    True Skin: Skin Treatments

    However, a cleanser should remove dead cells and a moisturizer should increase water content, protect skin, and smoothness. I’m wondering what you suggest as a good natural emulsifier.

    1. Avatar
      Perry Romanowski

      Useful emulsifiers do not occur in nature and any one that is used in cosmetics would have to be produced in a laboratory. Whether you consider it natural if it is derived from coconut oil is really a matter of opinion. There is no legal definition for “natural”.

  22. Avatar

    Do physical UV blocking agents like zinc and titanium need to penetrate the skin to be effective? Thanks

    1. Avatar
      Perry Romanowski

      Most likely not. Even nanoparticles of these ingredients haven’t been found to penetrate.

  23. Avatar

    Hello Perry,
    I was wondering if I am making a homemade self tanner using DHA, should I use a penetration such as Phosphatidylcholine because I actually want it to darken the dead skin cells.

    Thank you!

    1. Avatar

      DHA will penetrate the outer layers of the skin rather well so an additional penetration enhancer is not typically necessary. But it really depends on what is in the rest of the formula.

  24. Pingback:Advances in penetration of skin creams

  25. Avatar

    Thank you, Perry, for addressing this issue! 🙂
    Do you have any suggestion for cosmetic ingredients that form a good barrier against penetration of irritants (oclussives)?
    Another question: say one formula combines penetration enhancers like surfactants and PG with irritants like certain fragrance materials (most essential oils contain many irritants), should a cosmetic chemist rather try to avoid happening? (for example a shampoo or soap including essential oils)

    Many thanks!

    1. Avatar

      Silicones like Dimethicone are pretty good barriers.

      I don’t think you would generally have to avoid PG with fragrances unless you have a problem with a specific formula.

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