Serums have a heavy load. Tasked with calming, clearing or treating, built with powerhouse ingredients like niacinamide, vitamin C, and peptides, we expect a lot from them. But, if there’s just one serum your beauty arsenal should boast, it’s hyaluronic acid.

Hyaluronic acid (HA) has been a beauty buzz ingredient for a number of years now. Packed into a variety of products from serums and moisturisers to sheet masks, night creams, and lip products, it’s become a regular contender for something we should be getting our daily dose of.

The claim

Gentle on the skin barrier, making it a good choice for those with dry, dehydrated or sensitive skin, the word on the street is hyaluronic acid can improve the production of collagen, as well making the skin look plump with a youthful glow.

The science

HA is a humectant — a substance that retains moisture — and it is capable of binding more than 1,000 times its weight in water. Our bodies are full of HA as it’s naturally found in the skin, eyes, and synovial fluid of the joints. It is also used in the medical world, usually to treat bone and joint issues.

HA used in beauty and skincare products is primarily made by bacteria in a lab via a process called biofermentation.

The reason

We need it because as we age our skin produces less hyaluronic acid — along with collagen and elastin — resulting in less volume in the skin, hydration and plumpness. The epidermis gets a lower supply of moisture and nutrients, begins to thin and we notice the beginnings of lines and wrinkles.

The catch

The molecules of human HA are very large. So large, in fact, they cannot penetrate the skin when applied on its surface. Unless you have it injected, in the form of fillers, HA containing these large molecules would do very little when applied to the skin.

To solve this, scientists had to find an alternative formula that would give the results that naturally produced hyaluronic acid delivers.

There are six different sizes of molecules in HA and the different molecular weights penetrate to different levels of the skin. The molecules that reach the deeper layers of the skin are smaller with a lower molecular weight. These guys attempt to sustain the skin’s moisture content. Those with high molecular weights, on the other hand, remain closer to the surface. They tend to have the most visible results but a much shorter life-span.

Serums, creams, and masks with a mixture of molecule sizes are usually the most effective.

The routine

Hyaluronic acid serums should be applied to freshly cleaned skin each morning and evening. It’s best to use them on damp skin as they will take the water on the surface and draw it within, rather than taking moisture from under the surface of the skin.

Apply a thin layer of your favourite moisturising cream after a HA serum as this is what the HA will take moisture from, drawing it into the surface of your skin.

The products

The Ordinary Hyaluronic Acid 2% + B5 is a viscous serum containing three different molecular weights of hyaluronic acid (HA). In a bid to address the question of larger molecules not penetrating the lower levels of the skin, The Ordinary uses three forms of HA with varying molecular weights, as well as an HA crosspolymer. This allows the HA molecules to be absorbed into the lower lays of the skin, and provide hydration and visible plumping, without drawing water out of the skin.

Pestle & Mortar Pure Hyaluronic Serum is a lightweight fragrance-free serum which is super-hydrating and anti-ageing. This Pure Hyaluronic Serum combines multi-molecular weight hyaluronic acid with skin-softening panthenol in a formulation which diminishes fine lines & wrinkles, provides superior hydration and delivers an instant skin-plumping and firming effect.

Dr. Lancer 3D Hyaluronic Eye Serum is a concentrated, lightweight serum that directly targets the appearance of fine lines and wrinkles, puffiness and dark circles. This non-sticky formula contains 3D hyaluronic acid, SuperOx-C, and Vitamins B3 + E to make the delicate skin around the eye look smoother, tighter and brighter. The metal applicator provides a cooling effect while the serum helps reduce the appearance of aging.