Hyaluronic acid (HA) naturally occurs in the body mainly in the joints, skin and eyes. It is a linear polysaccharide, a glycosaminoglycan. The highest percentage of HA in the human’s body, is found in the skin. In the epidermis, the outermost layer of the skin that is the protective barrier, HA acts as moisturizing factor. As we age, hyaluronic acid as well as collagen and elastin slow down . Consequently, the skin loses volume, the face is less plump and it is more dehydrated. HA enhances hydration of the skin.

Belongs to the humectants (water-absorbing substances) like glycerin, the all-time star that remains a key ingredient for hydration.

As a humectant, HA draws the moisture from the environment or from the lower layers of the skin and holds it on the surface. There are several types of HA. Low molecular can better penetrate the lower layers of the skin. High molecular can’t penetrate and remains on the surface. It has to be combined with occlusives and emollients.

Possible benefits

Acts as a moisturizing factor

Has anti-aging properties

Increases skin’s elasticity

Can heal wounds or repairs scars.

Different molecular weights of HA

Molecular weight is measured in kilodaltons, kDa.

High molecular weight remains on the surface of the skin and protects against Transepidermal Water Loss (TEWL).

Medium molecular weight acts in the middle layers of the epidermis. Boosts hydration and should give a smoother appearance to the  skin.

Low molecular weight (it can actually be very low) deeply penetrates the skin and helps would healing and seems to have anti-aging properties.

However, very low molecular weight may cause inflammation and irritation. If in a skincare routine are used several serums, all of them containing HA with various molecular weights, it is probable to happen.

Names you may see on the label of a product

Hyaluronic acid, which means high molecular weight just to retain moisture on the skin

Sodium Hyaluronate, a salt, penetrates deeper in the epidermis due its lower molecular weight.

Hydrolysed Hyaluronic Acid chemically broken down into smaller molecules for a better absorption.

Hydrolysed Sodium Hyaluronate, a very small molecule that could cause inflammation. There is actually a controversy about this issue.

Can be combined with any other active ingredient such as vitamin C, retinoids, AHAs, BHAs and PHAs, ceramides, peptides and niacinamide.

Precautions

HA theoretically has many benefits for the skin but it can’t be considered as the miracle ingredient in the skincare. In fact, no active ingredient can be evaluated as such. If you feel that its use irritates or dehydrates your skin then choose a moisturizer without it. We are not all the same. What can be good for your skin may not be for mine. This is what you should always keep in mind when buying cosmetics.

The hydration that it offers is superficial. The wrinkles reduction that occurs immediately after its use is temporary.

The bottom line: The use of HA may have many possible benefits but it is not always well-tolerated .There are other ingredients that can hydrate your skin.

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