I’ll get right into it. This article from Harper’s Bazaar titled “Are You Misusing Hyaluronic Acid?” has been making the rounds for a while and causing quite a stir, making people wonder if hyaluronic acid is bad for their skin. We’ll be looking at the article today and the accuracy of its claims.

For more background, continue reading the next few paragraphs or skip to the next image to get straight into the article.

I’ve been aware of the article for quite some time but also had an interesting experience in a popular Facebook group where a celebrity esthetician was asserting that tretinoin and hyaluronic acid were damaging to the skin. When pressed for actual evidence via medical literature to support her claims, she became increasingly condescending and defensive – clearly annoyed the group wasn’t just accepting her word on it because she had a license. Her citation given later on was the HP article – where she’s conveniently featured.
Note: I respect estheticians 100% but that doesn’t make you an expert on topics outside your license and you should still be able to cite sources in that case.

As someone who dedicated to addressing misinformation and marketing, I felt I had to do a post on this when I saw it come up again recently. I’m going to try and not get too “ranty” here but I also have to admit this article is beyond frustrating. How can you claim to be clearing up the myths and truths while sharing misinformation? This article is also full of flawed logic and either they’re not understanding what they’re citing or worse – they’re intentionally manipulating it.

I don’t want to stir the pot too much and I’m certainly not the ultimate authority on skincare. But I’m hoping that by doing this post, I can show you why it’s important to question the information we’re given and why we should insist that experts gain our trust by backing up their assertions with science.

• 

This article may contain affiliate links and codes. They add no cost to the reader but help support the author and her content.

What is Hyaluronic Acid?

Hyaluronic acid is a mucopolysaccharide, a long chain sugar naturally occurring in the body. Another term for this is a glycosaminoglycan, also correct. HA is a polymer, meaning it’s made up of repeating subunits, and structurally it’s a long, unbranched chain.

As you can see in the image below, its monomers N-Acetyl Glucosamine and Glucuronic Acid are alternated to form its structure. These “building blocks” for hyaluronic acid are also considered its precursors as a result.

The image above also tells us that it’s a humectant. The molecular structure of a molecule can tell us a lot about it and for humectants, they need to be polar as well as be able to form hydrogen bonds with water via NH and OH groups. Instead of linking you to a bunch of mentions in the literature, I’m going to refer you to biochemist Michelle’s blog post on this. She does an excellent job summarizing how to identify humectants for those of you wanting to learn more.

Humectants attract and bind moisture. For a refresher on humectants, the skin barrier, and the benefits of skin hydration make sure you’ve read my Skin Hydration Deep Dive where I really get into how the skin retains moisture and the many benefits of more hydrated skin from its appearance to better wound healing and mediating inflammation. Hyaluronic acid in particular is used topically in skincare products but it’s also naturally occurring in the body. It’s an abundant molecule in the body, helping make up the extracellular matrix (ECM). You’ll find it in joint and eye fluid, as part of the Natural Moisturizing Factor in the skin barrier, in the dermal matrix, and more.

Hyaluronic acid serves many key functions in the body, from helping with tissue hydration to aiding in wound healing. In addition to its use in cosmetics, you’ll also find it cross-linked in dermal fillers and it’s used for medical applications like wound dressings.

So what’s the big deal? Why would the Harper’s Bazaar article say it’s detrimental to the skin?

The Harper’s Bazaar Article

Summary

The article discusses the popularity of hyaluronic acid and the marketing claims and then goes on to say that many “experts” have raised concerns and are asking where HA in products comes from, where the moisture it attracts is coming from, and if too much hydration is a bad thing. It then goes into how HA in cosmetics is synthetic and chopped up, you can’t compare topical HA to the endogenous molecule in the body, how it’s inflammatory, and other concerns.

The Claims and My Response

For the sake of time and not boring you all to tears, I’ll be responding to their main assertions below. If I don’t cover anything you’re really interested in hearing my response to, let me know in the comments.

“The synthesized stuff in skincare products is usually “hydrolyzed hyaluronic acid” or sometimes “sodium hyaluronate” (the salt derived from hyaluronic acid).”

Not technically true. Hyaluronic acid becomes sodium hyaluronate at physiological pH. Sources here and also here.

“None of the chemists or dermatologists BAZAAR consulted could provide data demonstrating that lab-created, cosmetic-grade HA actually holds 1,000 times its weight in water, although plenty of studies do point to its “significant” water-drawing capabilities.”

This is really just a Strawman argument in my book. They’ve brought up a point completely irrelevant to the issue so that when they debunk it, it’ll lend them more credibility. The “HA holds 1000x times its weight in the water” thing is brand marketing and whether it’s true or not has really nothing to do with whether hyaluronic acid is effective in skincare or safe.

The real question should be whether it’s an effective humectant and skincare ingredient. And they’ve kindly answered that for us, pointing out that many studies mention its “significant water drawing properties.” That’s the important part here, not the random marketing misinformation. In the very next line they then try to claim that topical HA has limited water drawing ability but their citation is a description of the ingredient from a cosmetic supplier.

“Although Paik supports the use of HA in general, the dermatologist admits that “smaller HA molecules set inflammation in motion,” referencing the many, many studies that show low molecular weight hyaluronic acid has a pro-inflammatory effect on the skin.

This is where I begin to get annoyed. They add citations to make these claims appear legitimate yet their citations are either not from credible sources or the research cited doesn’t say what they claim it does.

First up, their “many, many studies.” At the beginning of the article, they stress that you cannot use research on how endogenous HA works in the body and apply it to topical use. Yet here they are, doing that very thing.

Let’s look at what the article they’ve cited, “Hyaluronic Acid in Inflammation and Tissue Regeneration,” actually says:

• It has been shown that HA fragments of different molecular sizes can display different, sometimes opposing properties. For example, it has been well documented that HMWHA displays anti-inflammatory and immunosuppressive properties, whereas LMWHA is a potent proinflammatory molecule. A proposed hypothesis suggests LMWHA may have a different biological function than HMWHA, such as to inform cells about stress conditions.⁷  Clearly, they read this and then stopped there. They accused others of “oversimplification to the point of misinformation” in regards to HA benefits but then do the same. Inflammatory does not automatically equal bad for skin – inflammatory molecules serve key functions just like reactive oxygen species do. It’s only unnecessarily high levels or chronic inflammation over time that is an issue.
• It has been proven that HMWHA displays anti-inflammatory activity, whereas low molecular weight degradation products of HA can induce inflammation.³⁶ It has been reported that LMWHA may elicit various proinflammatory responses such as activation of murine alveolar macrophages,³⁷ or induction of irreversible phenotypic and functional maturation of human dendritic cells.^38,39 Further studies have shown that small hyaluronan fragments increase the expression and protein production of several cytokines such as MMP-12, plasmogen activator inhibitor-1,^40,41 macrophage inflammatory protein (MIP)-1α, MIP-1β, monocyte chemoattractrant-1, keratinocyte chemoattractant, interleukin (IL)-8, and IL-12 by macrophages.^42-4 Still no mention of its inflammatory properties being detrimental, just that it acts differently than high molecular weight hyaluronic acid (HMWHA) and how it’s essential to many important processes.
• However, Ke and colleagues⁶¹ demonstrated strong antioxidant functions of LMWHA, which has shown protective effects against ROS both in vitro and in vivo, and inhibits lipid peroxidation and scavenges free radicals. Moreover, LMWHA raises total antioxidant capacity in immunosuppressed mice. While HMWHA acts differently in the body, you can see that LMWHA also has antioxidant functions and other benefits.
• The conclusion of the article is very telling: Hyaluronic acid is present through all steps of the wound healing process not only as a component of the wound environment, but as a factor that actively modulates tissue regeneration. Along with studies that revealed the unique properties of HA, some attempts have been made to apply it in clinical practice, especially in chronic wound treatment. And: Hyaluronic acid as a biologically active molecule that regulates tissue repair process on multiple levels should be considered as a safe and effective option to be used in skin repair. No mention of LMWHA being detrimental to skin or our bodies in any way and they conclude by saying HA in general is a safe, effective method in general for tissue repair.

“The best available science points to the fact that low molecular weight HA is “able to bind to TLR receptors and consequently initiate the signaling cascade, leading to the production of proinflammatory cytokines and chemokines in various types of cells,” as one study says. In layman’s terms, it triggers an unnecessary immune response—a sign that the body is attempting to protect itself from a foreign invader.”

The “best available science” is apparently one study. And that one study? They’re just citing the same one from above again which we just covered.

We’ve just looked at the contents of that study so to summarize it as LMWHA “triggers an unnecessary immune response – a sign that the body is attempting to protect itself from a foreign invader” is patently false.

They then contradict themselves again in the next paragraph, saying HA has value as a humectant but then add:

“Still, the above may help explain why—in this age of hyaluronic-acid-in-everything— people are reporting more adverse reactions to the ingredient.”

The next part of the article details evidence of these supposed adverse reactions:

• One star reviews of products with HA
• Influencers and bloggers removing HA from their routines
• Posts in Facebook groups and Reddit
• Usage warnings for products containing much more than just HA

I wish I was kidding. It was at this point in the article I had to step away and grab a snack before I chucked my phone and gave up.

These examples are all purely anecdotal. Humans are inherently biased (including me,) and self-reported claims like this are notoriously unreliable. Actual research has clear parameters in place to limit bias and variables tainting the results for example while these reports could be due to other skin issues, other ingredients in the products, and more.

Thankfully, they debunk their own point themselves later in the article:

“But what about all the hyaluronic acid devotees that swear the ingredient has saved their skin, I ask? To which Ouriel replies, “You can’t determine what ingredient is benefiting your skin unless you eliminate all the other ingredients, and in skincare, you have at least 30 other ingredients [in one routine].”

Paik takes the same-but-opposite approach, pointing out that it’s equally as difficult to determine what ingredient is irritating your skin. “People are using so many things on their skin, and you can blame anything,” she says.”

As far as the benefits of HA from personal experience, in this day in age there are very basic serums with water, HA, and preservative only like the Cos de Baha serum I use for microneedling. Something like that would make it fairly easy to determine if HA is beneficial for your skin but also exactly – HA is a single humectant in what hopefully is a diverse, well formulated product with an array of ingredients all aiding in increasing hydration of the skin and barrier function.

“A client had an immediate reaction to something [during a treatment] and I was like, ‘What’s going on here?’” she tells BAZAAR. “The product had three different molecular weights of hyaluronic acid in it.” The incident inspired years of research, trial, and error and today, Schook recommends that her clients remove HA from their routines completely.”

This is the esthetician mentioned at the start of the post. Again, could have been anything. Even if they had sent the client for a patch test to give us some more accurate data here, everyone has unique skin and individual triggers. Doesn’t make an ingredient problematic for everyone else. Where’s all the research she’s done?

She then says she suggests everyone stop using all HA products…. not just the low weight, all HA. At this point, the article is making less and less sense. Prior to this, the article had said only LMWHA since it’s pro inflammation – though we already debunked this and didn’t they say we can’t compare how HA acts in the body to topical use anyway? If she recommends not to use HMAHA as well then she should be suggesting everyone quit humectants entirely then. She does address HMWHA further down, which I’ll get to, but at this point in the article nothing is adding up.

“It’s widely reported that topical hyaluronic acid grabs moisture from the atmosphere and draws it into your skin…but there appears to be no research that proves HA sources water from the environment. “There’s really not a lot of water in the air, even if you lived in a steam room,” Wendy Ouriel, a cellular biologist and founder of Oumere, tells BAZAAR. (Studies confirm that water vapor content ranges from 0.2 percent to 4 percent.) Finding the atmosphere lacking, “hyaluronic acid is going to pull directly from which it’s attached,” Ouriel says: your skin.

Even in the most humid, tropical, 4-percent-water-vapor conditions, hyaluronic acid will theoretically resort to slurping up the moisture that sits within your skin—and within your own hyaluronic acid stores—and pulling it to the surface. This will temporarily make the skin appear hydrated and smooth, but moisture on the surface evaporates (perhaps why the skin’s innate wisdom prioritizes lower-level moisture),”

And there it is. The most commonly repeated myth about hyaluronic acid and one based on no evidence at all. In addition to not being supported by anything, it doesn’t make sense.

Heres why:

20% of the skin’s water is in the skin. Of that water, 60-70% is in the dermis specifically. Source.

The dermis is vascular, meaning it has its own blood supply via its capillaries, and this means the tissue is rehydrated via circulation. The epidermis must rely on diffusion from the dermis for nutrients and moisture as well as its own humectants, the NMF which is within the corneocytes of the skin barrier and attracts and binds moisture.

The epidermis is the most superficial and therefore exposed to the environment- it’s constantly losing moisture due to factors like skin barrier function, cleansing, weather, indoor heating, and more. So drawing moisture outward from the water rich dermis (which is rehydrated ) to where it’s needed isn’t a bad thing.

There are mentions in the literature of humectants drawing moisture from the environment actually but it’s stressed that this is a secondary source and not necessary for them to work. Humectants “are basically hygroscopic compounds which mean they attract water from two sources, from the dermis into the epidermis and in humid conditions from the environment.” Humectants are supposed to draw moisture from the dermis.

The same article I quoted above also states that humectants can draw moisture to the surface and evaporate and therefore you just want to combine with an occlusive. This is widely known, supported by research, and recommended by countless derms. Problem solved.

I also want to add that above Ouriel states that this is all “theoretical” and doesn’t cite any evidence… that says it all for me.

“Of course, HA devotees claim you can circumvent this effect by applying the ingredient to damp skin, or by following up with a water-based moisturizer. “Then you’re negating everything,” she counters. “Because it’s just going to absorb the water on your skin, and it’s not going to go into your skin, so what’s the whole point of it?” Eventually, that surface-level water evaporates, leaving no long-term benefit behind.”

“HA devotees?” Just sounds like consumers who enjoy hydrating products and know how humectants work to me. Again, purely theoretical. Using a moisturizer to stop moisture loss from occurring after applying humectants is a common practice recommended by many derms and you’ll see it referenced often in scientific literature. Where’s the evidence? That’s what I want here.

It also just makes no sense. Our skin’s own humectants, aka your Natural Moisturizing Factor, are located in the most superficial layer of the skin: the corneocytes that make up the skin barrier along with epidermal lipids. They’re on the surface of the skin too yet manage to work just fine.

As far as moisture on the skin rendering HA useless… water based products with their ingredient are 50-70% water anyway as it is. There is some limited data showing HA can diffuse into the skin too. It’s also not a black and white topic – molecular weight, formulation and added penetration enhancers, and devices and tools can all impact absorption levels of HA. And we also have no evidence I’ve found that humectants acting superficially aren’t still beneficial.

A 2018 study funded by Estée Lauder found that, in humid environments, topical HA “created a false increase in apparent water content exacerbating water loss rate;” meaning, it made skin look hydrated by pulling moisture to the surface, but actually led to dehydration.

Finally, some research. Hallelujah.

Sadly, it’s been either manipulated or misunderstood yet again. They used ex vivo human skin explants for this and their own study concluded with the following in regards to the reliability of using this versus actual skin for research:

“The results in the present work strongly suggest the need for future studies that make use of improved model systems, increased subject numbers, and perhaps a pivot to in vivo experiments. For the reasons discussed above, improved tissue sources and model systems should be explored. 

Ultimately, however, these experiments should transition away from model systems to in vivo studies. Skin culture models are only a way to prolong the eventual decay of ex vivo skin tissue, and dehydration/rehydration models can never fully match real dry skin.”

If you just heard a noise, that was me facepalming all the way over here in California. Yeah, that really makes me trust the results when the entire article they mention the discrepancies between the model and real skin and most of the conclusion is devoted to this.

Their big finding was that the corneocytes didn’t retain the hydration from topically applied HA. This was also true of the glycerin though, no occlusive was used, issues with the models used, and even if it’s somehow true – does anyone apply a hydrator thinking it will last them any longer than the next morning?

A 2016 study found that low molecular weight hyaluronic in acid (also known as short-chain HA)increased water loss by over 55 percent.

What they conveniently leave out is the study found that “TEWL was reduced by 27.8% with RHA, and by 15.6% with HMW HA, but increased by 55.5% with LMW HA.”

TEWL is trans epidermal water loss. So their study found that HMWHA actually reduced water loss from the skin, in direct opposition to what they said above about HA in general. By the way, this is because HMWHA is film forming. LMWHA is not so without any occlusive, it will evaporate and worsen water loss. Nothing we don’t know and it’s easily fixed.

“Considering the well-researched relationship between LMW and inflammation, some say high molecular weight, or long-chain hyaluronic acid (HMW HA) is the way to go.”

No. Just stop.

I can’t take much more so it’s fortunate that we’re down to the last claim I’ll be addressing:

Mary Schook is back again to tell us how even HMWHA is bad because it’s a sugar and can feed dermatophytes. There’s plenty of citations to convince us she really knows what she’s talking about.

… Except these citations are links to Wikipedia, blog posts on nail fungus, and 2 research articles just covering things like the definitions for hyaluronic acid and fungi on the skin.

I’ve abandoned all attempts to not sound too ranty. It irritates me beyond belief that articles like this mislead consumers. There is not a single scrap of evidence mentioned that actually shows that topical HA application leads to an increase of yeasts like Malasezzia on the skin.

We’re also back to contradicting ourselves I see. Schook says “the wetter the skin, the easier the invasion of the dermatophyte” yet Ouriel says the “surface-level water evaporates, leaving no long-term benefit behind.” So which is it? Is HA leaving the skin wet or drying it out?

It’s not like we’re leaving the skin wet anyway but let’s see what the article “Influence of hyaluronic acid on bacterial and fungal species, including clinically relevant opportunistic pathogens” says:

• Hyaluronic acid (HA) has several clinical applications (aesthetic surgery, dermatology, orthopaedics and ophtalmology). Following recent evidence, suggesting antimicrobial and antiviral properties for HA, we investigated its effects on 15 ATCC strains, representative of clinically relevant bacterial and fungal species.
• The results showed that different microbial species and, sometimes, different strains belonging to the same species, are differently affected by HA. In particular, staphylococci, enterococci, Streptococcus mutans, two Escherichia coli strains, Pseudomonas aeruginosa, Candida glabrata and C. parapsilosis displayed a HA dose-dependent growth inhibition; no HA effects were detected in E. coli ATCC 13768 and C. albicans; S. sanguinis was favoured by the highest HA dose.

Additional research that contradicts the HP article and Schook’s claims:

“Hyaluronic acid sodium salt gel 0.2% is a topical device effective in reducing skin inflammation.
The objective of this study was to evaluate the efficacy and safety of a topical anti-inflammatory containing low-molecular weight hyaluronic acid. 

These authors have also shown that skin treated with increasing concentrations of LMWHA induce a progressively higher antimicrobial effect when compared to untreated skin. The stimulation of skin innate immunity by LMWHA is a potential mechanism by which hyaluronic acid sodium salt gel 0.2% exerts its beneficial effects in reducing the signs and symptoms of seborrrheic dermatitis.” Source

It’s not conclusive but at least I’m citing something vs trying to scare people away from hyaluronic acid with theories and horror stories.

Again, for the many benefits of skin hydration see my previous blog post.

The Wrap Up

I knew this article would frustrate me but the more I got into it for this response the more I realized the extent of the contradictions, misinformation, misleading citations, and logical fallacy. I do want to stress that I actually didn’t have as much of an issue with the dermatologists quoted – their responses tended to be much more balanced and they’re not responsible for the rest of the article.

I’m going to just move away from the contents of the article now and there’s not much else to say and I don’t want to end on a negative note.

As far as hyaluronic acid, here’s what I think you should keep in mind:

• It’s a humectant and has been shown to improve skin hydration but aside of the benefits linked to overall skin hydration, it doesn’t do much else and the hydration won’t last past that day (half life in skin is less than a day)
• It’s a supportive ingredient, not the star. Look for HA in formulations with other humectants as well as ingredients like niacinamide, ceramides, and cholesterol that support skin barrier health and function
• Apply on skin immediately after cleansing and lock in with an occlusive moisturizer to minimize water loss from the surface of the skin

I think the overall lesson here though is that that we shouldn’t allow someone to solely use their title to tell us they’re right. We need to insist that the information we’re given is grounded in science. If we insist that those we follow prove their arguments and hold them accountable, it better serves us and the skincare industry as a whole.

Thanks for reading to any who made it this far. I’ll be over here applying my hydrating toners and serums if you need me hehe.

As always, add your thoughts on all this in the comments’