Think of your serum as the main course in your skincare routine. Post cleansing, it's a way to deliver high concentrations of specific ingredients to the skin.

Usually in clear, gel-based or liquid form, serums can deliver hydration directly to thirsty skin prior to moisturising, which locks in all that hydrating goodness.

Here are five hydrating serums that'll help keep your skin's youthful glow and moisture levels up this summer:

BIOMIMIC Skincare Ultra Hydrator Advanced. From new Australian brand Biomimic this oil-free, lightweight formulation contains a powerful and potent combination of hyaluronic acid, vitamin B3, B5, and peptide complex to revive dehydrated skin and balance out your skin's pH levels.

iS CLINICAL Hydra Cool Serum. Formulated with hyaluronic acid (touted as nature's most powerful hydrator), as well as vitamin B5, and antioxidants from essential botanicals and bio-nutrients, this cooling serum penetrates and protect even the most sensitive skin.

It can even be applied to sunburned skin to rehydrate and cool.

La Roche Posay Hyalu B5 Hyaluronic Acid Anti-Ageing Serum. Enriched with vitamin B5 and madecassoside to target wrinkles, loss of volume and elasticity, this serum is designed to repair and replenish sensitive skin.

The Ordinary Marine Hyaluronics. An ultra lightweight, marine-derived formula designed to attract and hold water within the skin to minimise loss of hydration.

Boost Lab's 2D-Hyaluronic Hydro Boost Serum. Designed to strengthen the skin's moisture barrier to calm and smooth even the most sensitive skin.

Delivers fast, effective hydration and helps to plump the skin.