What is hyaluronic acid?

In recent years, hyaluronic acid has gained celebrity status in the world of skincare and is now a star ingredient in many cosmetic facial products and injections.

You may have seen hyaluronic acid products dominate the cosmetics industry, but did you know that your body naturally produces this substance?

Hyaluronic acid is found in your eyes, the connective tissues surrounding your joints, and your skin. It's a humectant, meaning it retains moisture.

For your tissues and cartilage, this provides cushioning and lubrication which can prevent wear and joint pain. For your skin, this means hydration - an all-important feature of good skin health.

Dr Kristina Semkova, consultant dermatologist at the Cadogan Clinic, says: "Hyaluronic acid, despite its name and unlike other skincare acids, does not exfoliate but instead hydrates the skin by attracting and holding water. In fact, it can hold 1000 times its weight in water, and this gives volume to the skin and reduces fine wrinkles."

Is hyaluronic acid good for other skin issues?

If anti-ageing isn't your number one priority, don't be fooled into thinking that's all hyaluronic acid has to offer.

By helping your skin cells to draw in moisture, hyaluronic acid helps to keep your outermost layers of skin - called your skin barrier or lipid barrier - healthy and functioning.

A healthy skin barrier protects you from harmful external elements, such as ultraviolet (UV) sun rays, germs, dust, and pollution.

Is hyaluronic acid good for acne?

Yes, the bacteria that cause l'acné are able to penetrate your skin more easily, making it another common sign of a damaged skin barrier.

Semkova says: "Hyaluronic acid can help reduce the redness associated with acne and also help protect and improve the skin barrier. It won't prevent acne, but it may help with treating some of the symptoms."

Clinically administered hyaluronic acid injections are proven to be particularly effective in treating acne scars. By reducing the depth of the scars, this treatment can be very important in improving the mental wellbeing and self-esteem of many acne sufferers.

Semkova says: "Because hyaluronic acid is a natural part of the skin, allergic reactions are very uncommon. Even those with sensitive skin should be able to reap the benefits.

"If side effects do occur, it is advisable to review the other ingredients in your skincare products or possibly look at the concentration of the hyaluronic acid - I would advise avoiding anything above 2% concentration, which may cause irritation."

Is hyaluronic acid safe to use while pregnant?

Not only is this substance safe to use while enceinte, but some experts believe it may even help unborn babies to develop, reduce the chances of fausse couche, and prevent early (premature) births.

Research into hyaluronic acid supplementation for pregnancy benefits is relatively new, and more studies are needed.

Hyaluronic acid can be applied topically - rubbed directly into your skin - or injected as a dermal filler. Injections are best at improving skin volume and plumpness, helping your skin appear more youthful. However, these are pricey once-in-a-while treatments.

Fortunately, using hyaluronic acid topically in your everyday skincare routine will leave less of a dent in your wallet. You also have a lot of choice when it comes to which skincare step to use it in.

All can benefit your skin, but according to Semkova, hyaluronic acid serum is the most popular choice.

She says: "Serums are specially formulated to penetrate the skin, and so hyaluronic acid serum may yield better results for those concerned with ageing and skin damage at a cellular level. This said, everyone has their own preference and skin types vary dramatically."

This will depend on which hyaluronic acid form you choose

"If you're using hyaluronic acid serum, apply it to damp skin," Semkova adds. "This will help to lock in even more skin moisture."

If you really want to make sure you're getting the best results possible out of your chosen product, you'll need to delve a little deeper - to a molecular level.

The size of the hyaluronic acid molecules - the smallest particles of a given substance - can vary in cosmetic products. Research suggests that this size matters because this determines its biological properties.

This is known as molecular weight, and it's measured in unified atomic mass units, otherwise known as daltons (1000 daltons represented as kDa).

Introducing hyaluronic acid to your skincare routine can provide a range of benefits. If you are seeking medical advice from a dermatologist, then you should discuss your skincare products with them before use.