With an ability to hold 1000x its weight in water, this moisture-boosting molecule is the secret to plump, glowing skin. Here's how HA works and why derms believe you need it in your skincare routine

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Skincare ingredient trends come and go, with many often proven to be unworthy of the hype. However, when it comes to hyaluronic acid (HA), this is refreshingly not the case. Here's why the power hydrator should be in everyone's skincare routine for softer, smoother skin...

What is hyaluronic acid?

Don't be put off by the word 'acid'. Naturally made by our bodies, hyaluronic acid (also known as hyaluronan) is a water-holding, gel-like molecule that's found in your skin, connective tissues and even your eyes - and it essentially acts as a lubricant to keep everything from drying out. It's therefore a no-brainer wonder ingredient for moisturisers, serums, masks and all kinds of skincare in order to top up what Mother Nature already gave us.

What makes it so effective? “In terms of hydration and moisture, we do not have any other ingredients that have the ability to hold 1000x its weight in water,” explains oculoplastic surgeon, aesthetic doctor and founder of MZ Skin Dr Maryam Zamani . “For this reason, HA is considered a gold standard ingredient for hydration.”

HA supplies dwindle as we get older, leaving skin drier and therefore more susceptible to showing the signs of wear and tear. “As chronic dehydration is one of the factors that can cause premature ageing, HA is a very important ingredient in terms of anti-ageing ,” comments Pedro Catala , pharmacist, cosmetologist and founder of TWELVE Beauty .

“It is highly soluble in water, which is why it helps keep the skin tissues so perfectly moisturised – and it is also a key component in the gaps between skin cells, making it a highly compatible and effective, skin-hydrating ingredient.”

Who’s it for?

For those with dry skin  types, HA is the one to beat. Greater hydration means greater suppleness, but also better elasticity, fewer wrinkles and an overall plumping effect. That being said, with hyaluronic acid levels falling for all of us as we age, it seems most could benefit from topping up our supplies. Catala also points out that it's well tolerated across all skin types including the most sensitive , meaning the risk of unpleasant side-effects is minimal. “If a consumer has an allergic reaction after applying a product containing hyaluronic acid, it is much more likely to be because of other ingredients – perfumes being one of the most common irritants,” he comments.

Age-wise? We’ve seen positive improvements to skin texture and hydration levels after incorporating HA-containing products into our regimes from our late 20s, into our 30s, 40s and 50s too. And we’re unlikely to stop any time soon.

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What should you use?

In terms of your HA-product of choice, a mantra of quality over quantity works best. With the ingredient cropping up in cleansers, moisturisers, serums and more, your money is most wisely spent on products that score highly on the potency and longevity scales. “As cleansers are washed off, this is likely to maintain the least amount of HA on the skin,” explains Dr Zamani. “Similarly, heavier creams and lotions may have other substances or ingredients in them that may hinder the absorption of HA fully.”

Her product of choice? Serums. “While I still advocate using HAs in creams and lotions, I think serums hold and penetrate deeper as they are more lightweight and concentrated in their content,” she says.

Hyaluronic acid has also made its way into cosmetic treatments , with huge success - women swear by the relatively new Profhilo , an injectable that uses 100% synthetic HA to add bounce and a smoother texture to the skin. Though it's often dubbed the new Botox, it's actually best used alongside it, as it's not as effective for filling lines.

Elsewhere in what's seen as a trend of the 'skinification of hair' - i.e. skincare ingredients now being used in haircare as we begin to look after our strands in the same way we look after our skin - there are even shampoos, conditioners and scalp products harnessing the power of HA.

Does size matter?

Yes - and, of course, how you use it. Generally speaking, the smaller the size of hyaluronic molecule, the greater the chance it will work on a deeper level. However, different types serve different purposes. 
”Low molecular weight means particles of a smaller size and therefore a better chance of penetrating skin more deeply – which is when you achieve that filler/anti-wrinkle action,” explains Catala.

“High molecular weight does not penetrate the skin, but instead creates a viscoelastic film that keeps the skin moisturised: this transparent film reduces the amount of water that evaporates from the skin, known as Trans Epidermal Water Loss (TEWL). TEWL, is in my opinion, one of the main causes of premature ageing.”

While low molecular weight HA is considered better for greater long-term hydration, both low and high types have their place. There's still a difference of opinion in the industry, but generally it's thought that combining the two could help ensure all bases are covered, as Catala confirms: “A mixture of both HA weights is desirable if you want to more deeply hydrate the epidermis and also seal that water in from the outside.”

Are there any downsides?

In a word, no - but experts do warn that while it's a suits-all hydrator, the smart way that it holds onto water is only useful in certain conditions. "Remember that humectants will only draw water into the skin in humid conditions," explains Cosmetic Dermatologist Dr Sam Bunting . "So it’s of no use on its own in an airplane or in deepest winter, for example."

It makes sense; if you need it to hold onto water, there needs to be some for it to grab. That's why most serums not only contain other hydrating ingredients, but also why it's best to use it within a routine, under an oil or cream to really trap in the moisture. "If it’s used as a moisturiser, it will work best in combination with other ingredients that act as occlusives - locking water into the skin - and those that repair the skin’s barrier, like niacinamide ," agrees Dr Bunting.

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What should you look for in your labels?

Catala recommends looking out for the following as a general guide:

Sodium hyaluronate: i.e. HA converted into a salt. "It usually refers to the big molecule (high molecular weight), which is better for creating a film that sits on top of the skin to prevent Trans-Epidermal Water Loss (TEWL)."

Hyaluronic acid: “This usually refers to the small molecule (low molecular weight), which penetrates more deeply.”

Hydrolysed hyaluronic acid: “This normally refers to a low molecular weight of HA, as the big original molecules have been ‘broken’ into small pieces to enhance skin penetration.”

How about hyaluronic acid in makeup?

Due to its popularity on our bathroom shelves, it was only a matter of time before HA made its way into our makeup bags. However, while the use of HA in skincare is generally encouraged, the consensus regarding its necessity in makeup  is less clear-cut. Essentially, it depends on the makeup used. According to Catala, its inclusion in lipsticks can be beneficial and HA-based serums can prove valuable as a hydration-boosting primer.

According to Dr Zamani, HA might have a place in your BB creams  or foundations, but she believes serums and creams provide a better level of hydration.

The bottom line? Seek it in your skincare first, your makeup second.

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Do hyaluronic acid supplements work?

Can HA’s drink form replenish your skin’s hydration stores from within? With liquid aids having made a splash on our chemist shelves in recent years, which is better - supplements or skincare?

“I would recommend topical HA as a first line, with the add-on of oral HA,” advises Dr Zamani. “There is a place for both in the market of anti-ageing,” she says.

Her reasons for this are evidence and results-based. “Some studies have found ingested HA improves skin moisture and treatment outcomes for those with dry skin, due to its contribution towards increased internal synthesis of HA,” she points out. “However most of these studies have been done in Japan and not elsewhere, so it continues to be a relatively new nutrient to help with dry skin,” she explains.

“Topical application of HA shows immediate hydrating effects that have a confounding improvement with longer-term use.”