Hyaluronic Acid

Today, we're going to talk about hyaluronic acid in all its forms - serum, cream, injections - and see why it has become the star ingredient in cosmetic marquess, as well as the number-one molecule in aesthetic medicine. However, some people are accusing hyaluronic acid of causing irritation and inflammation, and are banning it from their skincare routine.

I'm going to give you my opinion on the starification of this cosmetic ingredient but we're also going to discuss the particularities of this active ingredient, and how to use it correctly in your facial care and finally my product recommendations.

• 1- Hyaluronic acid: a powerful humectant
• 2- Cosmetic ingredients and abusive marketing
• 3- My cosmetics recommendations

"As we age, hyaluronic acid levels in the dermis decrease, and applying hyaluronic acid to our skin helps to combat the damage of time? Let's find out..."

Hyaluronic acid: A powerful humectant

Hyaluronic acid is a humectant, i.e. it captures a very large quantity of water, making it the active ingredient of choice for moisturizing cosmetics. Hyaluronic acid is naturally present in our bodies, in joints, muscles and, of course, in our skin. It is very useful for skin hydration, but also for wound healing.

Over time, these 3 elements are less and less present in the dermis due to sun damage, free radicals and glycation. This is why hyaluronic acid is used for injections in aesthetic medicine (lips, nose, dark circles, wrinkles) or directly on the skin in cosmetics.

The main advantage of hyaluronic acid in cosmetics is its high moisturizing power: just one gram attracts over 5 liters of water, providing an immediate effect by plumping the skin and improving the appearance of fine lines. The other advantage is that its texture is not greasy, so when you apply it, you don't feel any disturbing film and, above all, it's non-comedogenic.

Another special feature is that hyaluronic acid is equally effective whether you have dry or oily skin, but we'll come back to that later. But I don't think that all its interesting properties are the reason why hyaluronic acid is so prominently promoted by cosmetic marquess.

Hyaluronic acid is an essential component of the dermis, along with collagen and elastin, all three of which are produced by fibroblasts.

Hyaluronic acid and facial care

Yet virtually all marques cosmetics contain at least one hyaluronic acid-based product, as it is one of the most powerful humectants.

Hyaluronic acid used in creams or serums does not penetrate to the dermis, but only to the epidermis. And most products use hyaluronic acid molecules of different weights, with the larger ones reaching the most superficial part and the smaller ones going deeper into the epidermis, but not into the dermis.

On the other hand, hyaluronic acid is constantly being created and destroyed in our bodies. An enzyme called hyaluronidase destroys hyaluronic acid within 24 to 48 hours.

This is why the effects of a hyaluronic acid serum last only 24 to 48 hours. The same applies to injections of non-cross-linked hyaluronic acid: an experiment showed that 48 hours after an injection 84% of the injected acid had been destroyed. In fact, hyaluronic acid injected during mesotherapy sessions is degraded within 24-48 hours, but that's not the point.

The injected solution also contains vitamins and peptides, but above all, the microtrauma performed during the procedure will stimulate and regenerate the skin.

Hyaluronic acid was discovered in 1934 and has been extensively studied ever since, but we have to be honest: we don't have many studies on its anti-aging effect. We do have studies on its efficacy in wound healing, we have studies in aesthetic medicine, but when it comes to local application, we don't have much.

However, an interesting study was carried out on acne patients treated with roaccutane.

These patients generally suffer from severe dryness, and two types of moisturizer were applied, one with hyaluronic acid and one without.

As a result, patients who applied the hyaluronic acid cream experienced a marked improvement in skin dryness and acne. But apart from this study, not much is known about its anti-ageing properties.

Aesthetic medicine :

In aesthetic medicine, to combat this rapid resorption, hyaluronic acid is stabilized and cross-linked, i.e. bridges are created between the hyaluronic acid chains like a sort of mesh to make resorption more difficult.

Depending on cross-linking levels and molecule sizes, the hyaluronic acid used in injections is resorbed between 6 months and 1? years.

Hyaluronic acid can be injected into the dermis to improve skin texture, or subcutaneously to increase volume. Of course, hyaluronic acids injected into the dermis are thinner and degrade faster than hyaluronic acids injected into the cheekbones.

Injections can be used for anti-aging to treat wrinkles and restore volume, or for beautifying lips, dark circles or the nose.

Why has hyaluronic acid become a marques cosmetics favorite?

We may think it's because of its great moisturizing action, or because it's useful for all skin types, or because of its high tolerance, but we'll come back to that later. Another hypothesis is that its action is immediate, with no need to wait several weeks to see its plumping effect, unlike other active ingredients.

In my opinion, the cosmetics industry has been playing on confusion between the effect of hyaluronic acid injections and local application of hyaluronic acid.

It's paradoxical, because this emphasis on hyaluronic acid has been to the detriment of other active ingredients such as retinol, which do have an anti-aging effect, but are more complex to use.

However, even if hyaluronic acid doesn't really have an anti-aging action, it does have enormous qualities, as we saw earlier, so why have some skincare specialists decided to stop using it?

A few years ago, when I was working in a hospital, we often used a hyaluronic acid cream to treat wounds that couldn't be sutured, and what we quickly noticed was that after ten days or so, 10% of patients had quite strong allergic reactions.

In cosmetics, too, it's possible to have bad reactions to hyaluronic acid, but less frequently of course, because normally your skin barrier is intact, which wasn't the case for patients treated in hospital.

Nevertheless, if you notice redness or other unusual phenomena when applying hyaluronic acid, it's because you can't tolerate the very fine hyaluronic acid molecules, which can be pro-inflammatory, or that you can't tolerate other ingredients in this product.

If this is your case, my advice is not to insist on using your current cosmetics, but to try others before banishing hyaluronic acid from your skincare routine. I think it's always worth remembering that you can have a bad tolerance to any cosmetic product, and that one way to avoid this is to keep your skincare routine simple.

Now how to use hyaluronic acid correctly?

It all depends on whether it's a hyaluronic acid-based cream or serum. A moisturizing cream may contain various humectants, such as glycerine, emollients or occlusives. There is no particular recommendation, except that it is preferable to apply it to slightly damp skin to get the maximum benefit from the effects of hyaluronic acid.

But if you use a hyaluronic acid serum that contains only humectants, but no emollients or occlusives, the water attracted by the hyaluronic acid will eventually evaporate, and this can dry out your skin.

To combat this, always apply a moisturizer or sun cream containing emollients or occlusives. The exception to this is if you live in a very humid environment such as Southeast Asia, in which case the hyaluronic acid can use the water in the air to hydrate your skin and you don't need to use an occlusive over the hyaluronic acid.

Another recommendation I can make is that if you use a hyaluronic acid serum in the evening, don't apply a retinol cream immediately afterwards, as this will reinforce the action of the retinol, which will act more strongly than usual, and you risk having side effects.

Cosmetic product recommendations:

After applying this serum, you can apply a sun cream depending on your skin type, which will seal in the water in your skin and prevent it from evaporating.

If you have oily skin, you can apply a sun cream directly after using a hyaluronic acid serum, but if you have dry skin, you need to use a nourishing cream and a sun cream.