Our licensed healthcare provider will inject Restylane L under the surface of the skin. The active ingredient is hyaluronic acid, a chemical found in your body. It holds onto moisture, helping elastin and collagen stay together. Restylane L is an injectable filler formulated to plump up and add volume to your skin. This amazing dermal filler is perfect for adding fullness to your face and resolving moderate to severe wrinkles and folds in the skin.