#SkinSchool: Everything you really need to know about hyaluronic acid
Hyaluronic acid serum has earned a permanent place in many a skincare routine, and for seemingly good reason: this natural humectant is second to none when it comes to hydrating skin. But what exactly is hyaluronic acid, and how does it work? Here, the experts reveal everything you need to know, including the correct (and incorrect) ways to apply hyaluronic acid serums and creams, and the products that harness its hydrating powers best.
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What is hyaluronic acid?
HA is a sugar molecule and a natural humectant. It’s superior in terms of its ability to draw in water and hold it in the skin. “Hyaluronic acid is a naturally occurring substance in our skin and joints that decreases as we age,” explains aesthetic doctor Dr Barbara Sturm. This accounts for the skin’s tendency towards dryness as we get older. Although hyaluronic acid (HA) has ‘acid’ in its name, it has none of the exfoliating properties associated with other cosmetic acids.
How does hyaluronic acid work?
HA works to retain moisture in the skin thanks to its capacity to hold water (one gram of hyaluronic acid can hold six litres of H2O). That said, there has been some controversy around the actual merit HA has on skin hydration; sceptics wager that the HA molecules in skincare products are too large to penetrate the dermis, and that it needs to be delivered into the skin (via a treatment such as microneedling or mesotherapy) if it is to be truly beneficial.
A-list facialist Dr Frances Prenna Jones is an advocate of the mesotherapy option. “Some facials use ultrasound waves to help HA absorb, but optimum penetration is achieved by directly injecting it into the dermis,” she says.
What are the benefits of hyaluronic acid?
It’s worth keeping in mind that the skin is designed to keep external substances out: skincare included. So, no hyaluronic acid serum is going to work on the ‘deepest levels of the dermis ‘ – no matter what the brand would like you to believe. However, that’s not to say there isn’t a place in your routine for a good hyaluronic product.
Regardless of how deeply your HA product can penetrate, “it is an important part of a daily beauty routine because even binding water to the surface of the skin keeps it moist and fresh,” says Sturm.
Improving the water content in the skin strengthens its barrier, calms irritation and (temporarily) plumps out fine lines. “It also helps to repair inflammation, damage and environmental stress,” she adds. “The immediate cosmetic effect is amazing too – it’s wonderful under make-up.” HA in its original state and molecular weight carries no risks of irritation (although you will, of course, need to consider how your product was formulated, and the other ingredients inside it).
Are all hyaluronic acids equal?
In its original state, a HA molecule is too large to penetrate the stratum corneum (the skin’s outermost layer), which is why the best hyaluronic acid serums use innovative formulation techniques to dissect the original molecule into shorter-chain derivatives that can penetrate to a certain extent.
In simple terms, low-weight (short-chain) HA is smaller, and therefore penetrates the skin to a deeper level, while the high-weight (long-chain) HA molecules are good for hydrating the surface of the skin. A product with multiple weights will work on multiple layers.
How to use hyaluronic acid correctly
Hyaluronic acid may sound like a catch-all skincare hero, but harnessing it correctly is a little more complex than many brands let on. Think of HA molecule as a sponge. Able to hold over 1000 times its weight in water, it’ll soak up moisture from anywhere possible. In a very humid environment, HA will pull moisture from the air – but when your environment lacks humidity, it’ll seek that moisture from the deeper layers of the skin, pulling it into the upper layers (where your skincare sits). If you haven’t ‘sealed in’ that skincare, the moisture pulled up by your HA will then evaporate, leaving your skin more thirsty than it was before.
The solution? Apply your HA to damp skin (cue the face mist) as this will ensure there’s enough water present for it to soak up. Next: always seal in your serum. By using a moisturising cream or oil on top of a hydrating HA product, you’re putting on the metaphorical lid, ensuring all that hydration stays within the skin, rather than escaping into the air.
The best hyaluronic acid skincare to try now
New innovations in skincare mean that today, there are many options when it comes to using this famed humectant topically. A hyaluronic acid serum remains a classic option – applied before your day cream and SPF, it’ll soak into the skin, delivering day-long hydration benefits.
However, hyaluronic acid is no longer solely reserved for serums and day creams. Face masks, targeted treatments and potent boosters are ideal for delivering an advanced hydration boost to thirsty skin – there’s even a self-tanner that uses plumping HA to bolster your bronze.
Here, see our verdict on the very best hyaluronic acid products to try now…
