Hyaluronic acid is a hydration workhorse. Here is what it actually does and how to get the most from it.

Hyaluronic acid is a humectant — it draws moisture from the environment and from deeper skin layers toward the surface. Applied topically, it sits in the outer skin layers and helps the skin feel plumper, softer, and more comfortable. It does not repair the skin barrier or treat acne on its own, but it supports the routine by keeping the skin surface hydrated during treatment phases.

There are different molecular weights of HA: larger molecules stay on the skin surface and provide immediate smoothness, while smaller molecules may penetrate slightly deeper. Many modern serums use a combination of molecular weights for broader hydration coverage.

Apply hyaluronic acid serum after cleansing and toning, while the skin is still slightly damp. Pat it gently onto the face and neck, then immediately follow with a moisturiser to seal the moisture in. In dry climates, skipping the moisturiser step can actually cause HA to pull moisture out of the deeper skin layers instead of drawing it in from the environment.

Hyaluronic acid is compatible with virtually every other skincare ingredient. It pairs especially well with Vitamin C (antioxidant boost and brightness), niacinamide (barrier support and oil control), retinol (cushions the dryness that retinol can cause), and glycolic acid (hydrates after exfoliation). There are no common incompatibilities with HA — it is one of the most versatile ingredients in a routine.