The truth about hyaluronic acid is not what you think.

Question: What ingredient pops into your mind when you think of a hydrating serum? Chances are, it's hyaluronic acid. It is, isn't it? Totally called it.

Known as the hydrating powerhouse for all skin types, hyaluronic acid is by far the most famous and well-known ingredient in this skincare market. It's The People's serum. And the beauty shelves are positively bursting with 'em — from affordable to pricey and in-between, almost every skincare brand has a hyaluronic acid serum in their range.

But what if we were to tell you hyaluronic acid might not be all it's cracked up to be? Well, that's what happened when cosmetic doctor and founder of L'Orient Skincare, Dr Prasanthi Purusothaman (who goes by Dr Prasanthi) dropped by the You Beauty podcast.

Listen: Want to get the episode in your ears? Post continues below.

Speaking on this week's episode of The Formula, the GP and skin expert touched on whether hyaluronic acid really deserves all the glory it's been given. And you might want to sit down for this one, friend. 

It's gonna hurt.

Watch: How to get better skin while you sleep. Post continues below.

Here, we look at the truth about hyaluronic acid — and why it might not be the ultimate hydrating skincare saviour you think your skin needs.

What is hyaluronic acid?

For the uninitiated (where have you been, m'dear?), hyaluronic acid (HA) is something that actually exists naturally in the body and, as Dr Prasanthi explained, the natural form differs from what you might see formulated in skincare products.

"Firstly, hyaluronic acid is a humectant moisturiser, meaning that it works by drawing water usually from the environment into the top layer of the epidermis," said Dr Prasanthi, adding that it can hold up to 1,000 times its weight in water. "As we age, hydration levels of the skin reduce in part owing to lower levels of HA." 

Dr Prasanthi goes on to explain that while HA usually sits in the deepest layer of your skin, some of it exists in the upper layer of the skin within cells.

In its native form, HA appears as a very long polymer, called high-molecular-weight HA, which has a very large molecular size, greater than one to 1.5 million daltons, explained Dr Prasanthi. 

Confused? Still with us? 

"Given we understand most topical molecules need to be less than 500 daltons to penetrate the skin," said Dr Prasanthi, and able to "work through the lipid water resistant barrier of the outer skin layers," this is where experts have started to "observe issues with topical hyaluronic acid in skin care."

The issues! What are the issues? We hear you yell.

Dr Prasanthi goes on to explain that "true HA usually sits deeper in the skin than what topical skincare is able to penetrate." Meaning? "Topical HA in skincare is likely only hydrating to the level of the superficial epidermis, given the lipids in between cells provide resistance to water entering the skin."

Oh. 

Further to this, Dr Prasanthi said the formulation of HA varies, and more often than not we'll see cheaper ingredients or lower-molecular-weight HA that is often marketed to 'go deeper into the skin'. However, this kind of stuff only penetrates the skin superficially and can often end up causing inflammation and irritation.

As Dr Prasanthi explained, usually when damage to the skin occurs (e.g. a cut), your body will use its own natural hyaluronic acid to trigger an inflammatory response to repair cells and signals. However, "This can cause inflammation when it is not warranted, and even the promotion of new blood vessel formation which in patients may manifest as redness."

Meaning? If you're an avid user of hyaluronic acid and always experience irritation and increased redness — this could be a reason why. 

"If humidity is low or the percentage of HA too high, it can also dry out the skin and rather than drawing water from the environment and nearby skin cells." 

Which is largely... unhelpful.

"Some chemists argue that the water content in formulations are enough to buffer this issue. However clinically, in my experience, without an occlusive agent to seal in the hydration that is sitting more superficially absorbed by the topical HA, transepidermal water loss occurs and dry, flaky skin can ensue as it draws water from nearby cells."

As Dr Prasanthi noted, "It is important to note that more studies are really needed to validate some of the concerns around the true efficacy of topical hyaluronic acid as a hydrating ingredient in skincare and proposed pro-inflammatory and dehydrating effects."

So, how do we know if we should use it or not? 

Is hyaluronic acid for all skin types?

"I think what we need to understand is never to rely on one hyped marketed ingredient," said Dr Prasanthi. "I personally prefer to work with hyaluronic acid in an injectable capacity where I can ensure placement into the layers of the skin where I know they can bring about the most benefit i.e. the dermis."

With this in mind, Dr Prasanthi said there are still some promising studies around the use of topical HA when it comes to reducing the appearance of wrinkles and photodamaged skin, reiterating that if it works for you — that's great! 

"Some people love and swear by HA, and if that’s you that’s okay — as long as it isn't causing any side effects. I believe that each individual is different and I don't think I am in a position to tell people blatantly not to use it as it really is a case-by-case basis, even though I prefer other ingredients to hyaluronic acid personally and for my patients."

If you're an avid user of hyaluronic acid, Dr Prasanthi said her only advice would be to pair it with emollients or occlusives to seal in the moisture, rather than relying on a HA serum in isolation to hydrate the skin.

"If, however, you have been persisting and using HA and not really seeing results it could be worthwhile exploring other hydrating emollients, occlusives and even humectant ingredients with less marketing buzz around them: glycerin, shea butter, linoleic acid, ceramides, cholesterols, urea." 

"I like to turn to skin identical ingredients that mimic that outer skin barrier best, as well as ingredients like niacinamide and some alpha hydroxy acids like lactic acid that can actually build up ceramide levels in the skin with consistent use."

"In my experience, the patients that have had the biggest issues with HA have been those with sensitive skin: rosacea patients, perioral dermatitis patients, dermatitis, acne-prone skin," said Dr Prasanthi, adding those with an already compromised skin barrier and those prone to inflammation can experience dryness, flaking, stinging, burning and redness.

What are some other ingredients that are just as good, if not better?

"There are much better humectant moisturisers for the skin, such as trusty glycerin, which in studies has been found to correlate with skin hydration levels of the stratum corneum better than something like HA," said Dr Prasanthi.

Not only can glycerin help with skin hydration, but it also prevents transepidermal water loss, helping make your skin barrier more sturdy and improving dry, scaly skin (which is a helpful tip, coming into the chillier weather). 

Another goodie is polyglutamic acid. Heard of it? "It doesn’t have the irritation potential of HA and can increase your skin’s production of natural moisturising factors, which are a critical part of the skin barrier and add moisture into the skin." 

"I also enjoy the use of skin identical ingredients of the skin barrier: ceramides, cholesterols, lipids that build up that 'mortar' between the skin cells. 

Anti-inflammatory ingredients such as niacinamide is another great alternative, as consistent use encourages your skin to make more ceramides, improving hydration. 

"Urea is a water-loving molecule present in the epidermis as a component of the natural moisturising factor (NMF) complex," which Dr Prasanthi said is also "crucial for adequate hydration and integrity of the stratum corneum." 

"It improves skin barrier function including antimicrobial defences and plays a key role in regulating keratinocyte proliferation. This ingredient I find it particularly good for drier skin types, keratosis pilaris, etc."

So, be on the lookout for these kinds of ingredients if you're experiencing these kinds of side effects and hyaluronic acid isn't playing nicely with your skin. 

Because, as we've said before, skincare is not a one-size-fits-all kind of thing.

If you're looking for where to find these ingredients (all of us), Dr Prasanthi recommends products said as Experiment Beauty Super Saturated Barrier Support Concentrate, $28US, SkinCeuticals Triple Lipid Restore 242 Anti-Ageing Moisturiser, $214 and Regimen Lab Wave Serum, $55.

What are your thoughts? Are you a hyaluronic acid fan? Share your comments below.

Feature image: Canva/Mamamia.

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