You can use the serum under day and/or night cream, or on its own.
Darphin Éclat Sublime Dual Rejuvenating Micro-Serum, 30 ml, Skin Serums for Women, Does it feel as though your skin needs something more than just the care provided by a cream?. Characteristics: firms the facial contours restores skin elasticity hydrates and nourishes effectively restores freshness and youthful beauty to your skin How to use: Dab an appropriate amount of the serum gently into clean skin with your fingertips. With its high concentration of active ingredients, the effect it has on your skin is far more pronounced and faster than with a face cream. Apply to the face, neck and chest.