This face serum provides long-lasting 24-hour hydration and it soothes and moisturizes dehydrated skin. Hyaluronic Acid, a powerful moisturising active ingredient, combined with high concentrations of La Roche-Posay thermal spring water, fills the skin with moisture for 24 hours. Arginine and Serine are excellent at trapping water for intense rehydration. Infused with water, the skin is immediately plumped up. Optimum hydration levels are restored.