Ingredient School: Hyaluronic Acid

What it is?

Hyaluronic acid is a molecule your own skin already produces — it's not a harsh acid at all, more of a sponge. One gram can hold up to roughly a litre of water, which is the entire reason it ended up in skincare in the first place.

What it actually does:

On the skin's surface, hyaluronic acid draws moisture in and holds it there, plumping the surface and softening the look of fine lines caused by dehydration (not the same as the fine lines caused by ageing — worth knowing the difference before you expect it to do a retinoid's job). It doesn't build collagen or resurface skin; its whole job is

Who it's for:

Genuinely almost everyone — it's one of the few actives with no real downside, no sensitivity risk, and no "start slow" advice needed. The one nuance: it needs to be applied to damp skin and sealed with a moisturiser, or it can pull moisture from the deeper layers of skin instead of the air, leaving skin feeling tighter rather than plumper. Order matters more than the ingredient name.

Products to try

Beauty of Majesty's Korean skincare line includes a dedicated Hyaluronic Acid Moisture Toner ($34.99), designed as the hydrating first step before their Peptide Power range. Pat it onto damp skin straight after cleansing, then layer your serum and moisturiser on top while skin is still slightly tacky — that's the step most people skip, and it's the one that makes the biggest difference.