La Roche‑Posay Hyalu B5 Serum is a dermatologically developed skincare treatment designed for dehydrated skin showing signs of ageing, such as loss of volume, reduced elasticity, and emerging fine lines. This powerful formula combines dual-molecular weight hyaluronic acid, vitamin B5 (panthenol), and madecassoside to deeply hydrate, plump the skin, and support its natural barrier function.