Skin Penetration Enhancers - Friend Or Foe

Are We Dealing With Friend Or Foe In Skincare Ingredients?

Along with all the other misnomers and hype we have to wade through, including marketing put out there about cosmetic ingredients, good or bad, watchdog groups also want to muddy ones' thinking by making claims that penetration enhancers utilized in cosmetics and skincare are spreading poisons into our bodies at an alarming rate. But let's not get carried away from the actual science here or allow emotive jargon to cloud our judgment.

All of this theory and supposition I guess, is going to be based on ones own perspective of the science. Personally, after reviewing the science on penetration enhancers, I believe they are a good thing in relation to pharmaceutical and skincare performance since our skin acts as an impermeable barrier to anything that comes in contact with it. Skin creams used for fighting free radicals and the aging process would be worthless if we can't go any deeper than the immediate surface of the skin. Antioxidants, Herbal Extracts and Essential Oils couldn't perform of what they are intended without penetration enhancers, in fact some EO's are in and of themselves penetration enhancers.

Now remember, when we refer to penetration enhancers we are not discussing a delivery system of toxic ingredients like arsenic, strychnine, or supposed endocrine disruptors, or anything which we would remotely be considered poisonous to our bodies or what the EWG and skin deep database would wish to convey as such. The use of some penetration enhancers are also combined with nano particles in order to reach deeper within our bodies such as delivery of medications requiring them to reach the blood brain barrier, penetrating not only the stratum corneum and the epidermis, but also into and beyond the dermis layer. In the studies which follow we will look at the delivery systems and the benefits for their use.

Let's Peek At The Actual Science

PubMed excerpt makes this correlation in part:

"One long-standing approach for improving transdermal drug delivery uses penetration enhancers (also called sorption promoters or accelerants) which penetrate into skin to reversibly decrease the barrier resistance. Many potential sites and modes of action have been identified for skin penetration enhancers; the intercellular lipid matrix in which the accelerants may disrupt the packing motif, the intracellular keratin domains or through increasing drug partitioning into the tissue by acting as a solvent for the permeant within the membrane."

A more recent PubMed article concurs with further research:

"Novel techniques for drug delivery have been investigated in human medicine in recent years. The transdermal route of drug delivery has attracted researchers due to many biomedical advantages associated with it. However, excellent impervious nature of skin is the greatest challenge that has to be overcome for successfully delivering drug molecules to the systemic circulation by this route. One long-standing approach for improving transdermal drug delivery uses penetration enhancers (also called sorption promoters or accelerants) that can reversibly compromise the skin's barrier function and consequently allow the entry of otherwise poorly penetrating molecules into the membrane and through to the systemic circulation. A large number of fatty acids have been used as permeation enhancers. They have proven to be effective and safe sorption promoters. This present review includes the classification, feasibility and application of fatty acids as sorption promoters for improved delivery of drug through skin."

The problem is EWG and CFSC are among those that wish to label all penetration enhancers as "BAD", instead of separation of the proven science in support of their use for the safety and efficacy they provide the user. The critical analysis here is, if personal care products could do all the things many marketing claims state they could do, then women wouldn't be injecting Botox or Restylane. Which basically means, that if penetration of actual skincare products was any deeper than the actual dermis then injections wouldn't even be necessary.

No, Not My Olive Oil

I just recently learned that a group of dermatologists in the UK are now looking at Olive Oil as a penetration enhancer and may be making a determination on its' restricted use in products made for small children....I believe 6 and under was the targeted age group, but I don't currently have the parameters of the restrictions the skincare companies may be faced with.

Olive Oil is a fatty acid which has been shown to have promising results in this field of study, though limited compared to others in penetration enhancement. What I found interesting in doing more research is in a study performed in 2007 using in vivo they determined human skin is usually the preferred skin membrance to use in an absorption study. No animal model gives absorption values identical to those obtained in human skin. Something I have tried repeatedly to convey in past articles that animal studies will not and cannot extrapolate to human beings as much as EWG, CFSC and their skin deep database would love them to, nor can in vitro (petri dish) compare to contact with actual human skin. The stratum corneum has long been considered a major barrier to the penetration of topically applied chemicals despite what ideologues try to pressure others into believing without supporting evidence.

The effects studied are shown with four essential oils (rosemary, ylang, lilacin, and peppermint oils), and three plant oils (jojoba oil, corn germ oil, and olive oil) on the permeation of human skin. These oils were compared with three synthetic chemical penetration enhancers, one of which is ethanol, and though the penetration of the oils enhanced permeation, their effects were less than the ethanol.

Aminophylline was the ingredient in this particular study for enhancing its absorption into the skin.

What I found interesting on page 6 of the PDF, in figure 3 and 4 of the study and in the synopsis of the Journal of Cosmetic Science, out of all the oils used, Olive Oil performed the least in permeation of the skin.

So I have to wonder what is the motivation for these dermatologists in the UK to be concerned with this ingredient when Jojoba Oil appears to perform the best overall for enhancing penetration of other ingredients? Again this is the reason why jojoba oil is excellent for dissolving and controlling excess sebum and maintaining skins pH balance, and I personally love this wax ester for what benefits it offers to skin, including the fact it is rich in antioxidants.

EO's also performed much better for enhanced absorption as a result of this study compared to Olive Oil.

I personally love Olive Oil and its' anti-aging benefits for the body inside and out. I am not too concerned about its' effective use in skincare as a penetration enhancer because that is exactly what I want it to do. I find it to be wonderful for soothing many skin irritations, and the fatty acid profile is exceptional for topical treatment of skin ailments since it acts as a natural steroid due to constituents of natural sterols, squalene and polyphenols, helping to calm many skin issues. Plus other studies in Asia showed that it was the preferred oil for baby massage over mineral oil, since it is readily absorbed more easily, and offers more skin benefits for fighting irritation and dry skin in infants.

I also found some of the research provided by International Association of Infant Massage (UK) Chapter very interesting in relation to Olive oil used in infant massage for similarly what I described above. They may take issue with this set of UK dermatologists restricting this luxurious oil or any other which may be deemed a penetration enhancer.

Let's Look At Concurring Facts

Another Study was performed utilizing other fatty acids and ethanol determining the increased absorption and retention of cortisol within the skin.

This study was performed by Sherry Jung, Biological Sciences. She has been an HSEP Medical Volunteer, a Peer Educator for the Counseling Center, and has served as a Biological Sciences Representative on the ASUCI Legislative Council. She is also a founding member and the current editor-in-chief of Med Times.

"The current project by Sherry Jung has served to illuminate our understanding of the penetration of a common dermatological drug when used in combination with a custom synthesized polymer. The results obtained point to direct applications in the field of dermatology as the polymeric compounds may be further modified for targeted-drug delivery. The avenues of research in this area are numerous, and we anticipate ongoing investigations using novel polymeric penetration enhancers."

In one portion of the discussion as determined during the study, the skin structure is composed of three resilient layers: stratum corneum, epidermis, and dermis. The amalgamation of these transitional layers and their physical properties and physiological forces designates the skin as an ideal component in regulating absorption and retention. Absorption and retention are dependent on many factors, including pH, molecular weight, solubility, electrolytes, polarity, and especially the lipophilic/hydrophilic nature of the molecules involved. Furthermore, the effectiveness of topically applied therapeutic drugs is dependent upon the retention in skin layers and the transdermal absorption into specific target tissues.

Critical Thinking Versus Being Scared

Many ingredients' molecular structure are simply too large to otherwise penetrate the outer layer of our skin, so without fatty acids or a synthetic penetration enhancer, depending on your preference, a simple, basic skin cream will essentially just sit on top and do nothing but soften and create an additional barrier for preventing dehydration of the skin.

Furthermore, with all the research I have combed over in past few years including these latest studies above, molecular size of ingredients prevent most cosmetic and skincare products from going beneath the immediate skins surface without help to achieve penetration of the stratum corneum. Penetration enhancers are utilized to provide the deliverance of essential skincare ingredients which can have a cumulative or immediate short term effect on improving skin texture and it's appearance while using the product.

But what we really should be looking at, are these penetration enhancers carrying any other ingredients of concern into the blood brain barrier?.....the likelihood is slim based on the evidence of nano scale size particles being required in many instances to even come close to reaching the blood brain barrier. In fact, other non-essential ingredients, like emulsifiers, thickeners and preservatives will not permeate the skin due to their particle size no matter the catalyst used for penetration enhancement. And in past articles, such as what was in the EPA Report, even nano scale particle size will find great difficulty permeating healthy skin without a penetration enhancer acting as a catalyst. The diagram (left) simulates the depth of skin layers and conveys in relation of the surface of our skin to the blood vessels and lymph nodes.

I could not find a single study that actually determined the penetration of the blood brain barrier with cosmetic ingredients utilizing penetration enhancers, only the scare mongering and supposition perpetuated by EWG and CFSC without any peer reviewed studies to substantiate their claims.

Only those of pharmaceutical origin, which is exactly the purpose of penetration enhancers and nano science, were shown to be beneficial in this context of delivery of therapeutic drugs, but certainly should not be used to draw a conclusion that this extrapolates to cosmetics or skincare.

This is another scare tactic being used to take something positive within the medical field and twist it to the negative for self serving goals by trying to convince the public that these same penetration enhancers are carrying everything we place on our skin right into our circulatory system. And if this can be done on a medical patch it must somehow do the same within cosmetic and skincare formulations.....

Cosmetics and skincare are not generally associated with big pharma, nor are they medicines, so their structure is for the purposes of treating the surface layers of our skin temporarily and should not be correlated as one in the same with a pharmaceutical delivery of medication through patches requiring a systemic effect.  Because if they could perform as such, then they would require FDA approval and would be marketed as a "drug."

When it comes to skincare, I want my products to perform beyond simply just sitting on top of my skin.  If an additional benefit of delivery of any essential anti-aging ingredient (antioxidants or Retinol) can be enhanced into reaching the epidermis, including softening and reducing fine lines and wrinkles and sustain hydration of the skin, then that's the one for me.

It still is personal choice.....if you think penetration enhancers in skincare are doing far more to your body than treating surface layers of the skin, then by all means be wary, but remember, penetration enhancement is also not black and white....as it showed in the studies above, in some cases it requires a combination of ingredients and the perfect chemistry to achieve exemplary penetration of what the research was trying to achieve (therapeutic drugs), and the molecular structure of the ingredient being enhanced also plays a role.

As shown in these studies, natural chemicals also are penetration enhancers, so even with the use of an all natural skincare or cosmetic product, you will not be able to avoid these in any way, shape or form. Another reason to remember to take what the EWG and CFSC and their skin deep database state with a grain of salt, because frankly they can't have it both ways..... and sadly this fact seems to be lost entirely on much of the all natural, certified organic skincare, blogger, and book author community.

This is where critical thinking and a touch of common sense should be used, but alas, as I see in so many forums or blogs on these subjects, are usually prefaced with a firm belief based on an ideology, whereby ignoring the actual science when it doesn't suit an agenda they are pursuing. It is especially disconcerting when skin deep database simply places scores of hazard without the balance of actual risk to the consumer, or EVEN references an ingredient in such a manner when they have 100% data gaps....their clairvoyance of such things is mind boggling.

The fact is, eliminate (ban) penetration enhancers based on ridiculous theories void of all science or the (beneficial) constituents these same ingredients may possess, and the majority of your natural skincare products (including my own formulations) will disappear from the store shelves as well as their synthetically derived counterparts. Now that would be a travesty!

But hey, there's always Vaseline and water!