Hyaluronic Acid: Safe for Your Skin?

Photo source:  im-fabulous.com

I recently received an email newsletter from Skin Biology that claimed Hyaluronic acid can be damaging to skin.  This both concerned and intrigued me, given that Hyaluronic acid is so prevalent in skin care products and seems to be well regarded in the skin care industry.  Could there be valid concerns about Hyaluronic acid and how to really know?  I've reprinted the text of the email I received below:

Hyaluronic acid

By Doctor Loren Pickart

Hyaluronic acid (scientifically named 'hyaluronan') is a sugar-like molecule that can bind huge amounts of water (1000-fold of its own weight).

When applied to the surface of human skin, it may feel smooth and sensuous but will slowly wet the skin's outer protective proteins and damage the skin barrier. This can temporarily improve the look of skin but does not help its long term health. The outer layer of skin (what we actually see) is composed of keratinocytes. The signal that causes the skin to send new keratinocytes to the skin's surface is a dryness in the outer layers of the skin. Hydrating (wetting) the outer skin proteins slows or even stops the normal flow of keratinocytes to the skin surface. If the skin is kept wet, such as with the use of a hyaluronan, renewal is slowed and skin just ends up looking older.

Skin damaging cosmetic moisturizers are designed to push water into the skin and wet the outer skin proteins. Various detergents (but they may not be labeled detergents) and water-holding molecules such as hyaluronic acid often loosen the outer skin proteins so water can interact with them. But this weakens the skin barrier and lets in viruses, bacteria, and allergens.

In about 1997, there were studies from Denmark that found that oil/water skin moisturizers broke down the skin barrier. The concern was that this could increase infection in hospital patients. 

This means skin is more slowly replaced and damage remains longer. The best example is the 'cold creams' that women applied every night in the 1930s and 1940s. You may have seen these in old movies. Their skin was kept moist but these women ended up with horrible wrinkles.

Various polymers of hyaluronan are used as skin injectable skin fillers. Injectable form of hyaluronic acid are sold as 'not-from-animal' sources but they are derived from pathogenic bacteria. The FDA warns that the material contains small amounts of bacterial protein and this can produce allergic responses in time.

Hyaluronic acid in tissues speeds the spread of cancer cells. Anti-cancer therapies are being developed to lower hyaluronic acid in tissue to stop cancer growth.

Go the http://www.ncbi.nlm.nih.gov/entrez/query.fcgi and type in 'hyaluronan cancer' and you will get about 1,100 recent references.

So our recommendation is to use products free from hyaluronic acid and instead use biological oils as moisturizer agents. These compounds are time tested and work as the most natural way to hydrate skin without potential harmful effects.

Photo source:  www.lipsticklibrarian.com/

I'm not a medical professional, but I do evaluate medical information and its sources for a living (I'm a medical/clinical librarian).  So I decided to do a little investigating and critically appraise, to the best of my ability, this claim regarding Hyaluronic acid.

First, I looked at the source.  Dr. Loren Pickart has a PhD in Biochemistry (University of California) with undergraduate degrees in Chemistry and Mathematics (University of Minnesota).  So, he does have expertise that is relevant to this topic.  He is also the founder of a skincare company called Skin Biology, with products that claim to reverse skin aging with the use of copper peptides.  

Disclaimer:  The reason I'm on the Skin Biology email newsletter list is because I ordered several products from Skin Biology about 4 years ago - an eye cream, emu oil, and a scalp product.  I did not find the products particularly effective (although not substandard either) and have not repurchased.  I do remember that the eye cream smelled nasty, to the point where I wondered if it had gone bad.  

But anyhow, there could be some potential bias on Dr. Pickart's part considering he does have his own line of products to promote.  On the plus side, I do see that two different sites have been established - one to sell products and one for  scientific information on skin care, called The Science of Dr. Loren Pickart, PhD, which is currently under construction.   

Here is a listing of the things that Dr. Pickart avoids when making his products, which includes Hyaluronic acid (source link).  His concern, as stated here, seems to be that Hyaluronic acid plays a role in spreading cancer cells:

6. We avoid the following:

6.1 Formulations and moisturizers that are designed to push water into the skin, wet the outer skin proteins, and "puff up" the skin to make wrinkles and creases less obvious. The problem is that as such products loosen and wet the skin, they damage the skin barrier and permit easier access by bacteria, viruses, and allergens. The chronic wetness also inhibits the signals that tell the skin to send more keratinocytes to the surface.

6.2 "New chemical entities", that is, synthetic molecules that the human body has never been previous exposed to in our history. It requires decades to determine the safety of such molecules such as in the case of PCBs and DDT.

6.3 Plant extracts with the exception of a few ingredients such as vitamins that are used in the human body, and substances such as aloe vera that have exceptionally good records of non-allergic actions on skin. Most plant extracts are alien to human skin and, in time, may cause rashes and allergic reactions. Many plant extracts are substances to stop animals from eating them, such as poisons and carcinogens.

6.4 Types of collagen-inducing peptides that act like Transforming Factor Beta 1 (TGF-beta-1), a protein named because it caused normal cells to grow like cancer cells. Concerns have been raised that such types of molecules may speed the spread of cancers and play a role in kidney failure.

6.5 Hyaluronic acid (hyaluronan) because it plays a critical role in the spread of cancer cells.

6.6 Ingredients used as nerve inhibitors to relax muscles to reduce wrinkles. Long term cosmetic use of such ingredients may inhibit nerve function in the brain and other areas of the body.

6.7 Dyes and coloring agents.

Okay, I think I now understand Dr. Pickart's perspective.  So what do others say?  

Well, a CIR Safety Review on Hyaluronic acid on cosmeticsinfo.org states that a "CIR Expert Panel reviewed acute, short-term and chronic toxicological studies and concluded that they did not demonstrate any cause for concern. Hyaluronic Acid did not cause reproductive or developmental toxicity. There was no genotoxicity found in reverse mutation tests, micronucleus tests and chromosomal aberration tests" and "that there were no reported reactions to topically applied Hyaluronic Acid, further supporting that Hyaluronic Acid at levels currently used in cosmetics and personal care products applied to the skin should not be of concern."

This sounds really good, but who/what is the CIR?  Cosmeticsinfo.org is sponsored by "the trade association representing the cosmetic, toiletry and fragrance industry in the United States and globally. Founded in 1894, the Council has a membership of more than 600 companies including manufacturers, distributors, and suppliers of the vast majority of finished personal care products marketed in the United States."  This would be like going to a site sponsored by the pharmaceutical industry to get information about your medication.  Major conflict of interest going on here, which greatly enhances the potential for bias.  It does not mean that their claims are bogus, but does mean you cannot just take them at face value.

Disclaimer:  I'm not knocking the pharmaceutical industry, as I once worked at one of the largest pharmaceutical companies in the world and by and large had positive experiences there.  Bottom line, however, you have to approach information critically and take into account any potential for bias or conflicts of interest.

So ideally, to really get an accurate picture, you would need some type of systematic review/meta-analysis from an impartial party that looks at the original research and synthesizes it.  Barring that, you would need to evaluate the original research on your own.  Dr. Pickart had recommended searching PubMed using the search terms "hyaluronan cancer".  That will indeed give you oodles of citations (almost 2,500), but we are concerned with topical use of Hyaluronic acid.  So add "topical" to the search, and you actually start getting studies looking at the topical uses of Hyaluronic acid.  One study looked at a gel containing Hyaluronic acid vs. usual care to prevent contact radiation dermatitis in breast cancer patients.   Interestingly, the study was stopped before completion because the women treated with the Hyaluronic acid gel developed contact dermatitis at a significantly higher rate than those who were not. To see this abstract, just type in the number 22172912 (the PMID, a unique identifier) into the PubMed search box.

If you take cancer out of the equation and do a search using these terms "hyaluronic acid topical skin", you find some interesting articles.  I learned that for wound care, "Harnessing the therapeutic action of hyaluronan into a topical application of proven clinical benefit has proved challenging."  (PMID 22068141)  Another study did find that low molecular weight Hyaluronic acid resulted in significant wrinkle reduction in the eye area (PMID 22052267).  This one even had some interesting before and after pictures.   However, the concern that started this whole post isn't so much does Hyaluronic acid work (which is a whole 'nother topic), but is it safe?

11 lbs  of Hyaluronic Acid would cost you $3,672.90
(Source:http://www.makingcosmetics.com/Hyaluronic-Acid-p81.html)

So, from just this admittedly superficial examination of some of the research literature, I now know that Hyaluronic acid is being investigated for use in contact radiation dermatitis, wound healing, and wrinkle reduction.  There does not appear to be a concern among investigators regarding potential cancer causing adverse effects.  However, there also is not currently a significant body of evidence to support either the effectiveness or the safety of Hyaluronic acid for topical use.  Most of the existing studies are small with few patients enrolled, and small studies often fail to show statistically significant results, either negative or positive.  Bottom line, at least as far as I can tell, we just do not know yet if Hyaluronic acid could potentially damage skin, which could probably be said about any number of new skincare ingredients being introduced into the market.