Hyaluronic Acid

Hyaluronic acid is a humectant — it pulls water and holds it. Your skin already makes it; a serum simply tops up the surface layers so they look full rather than crepey.

One thing worth knowing, because it catches people out in a dry Australian winter: HA pulls moisture from wherever it can find it. In low humidity, that can mean from your own skin. Always apply it to damp skin and seal it with a moisturiser straight after, or it will leave you tighter than before.

Do that, and it is the most reliable plumping ingredient there is — and it layers with everything. Good partner to PDRN and niacinamide.