Dermal fillers are a type of cosmetic injectable used to restore volume, smooth out wrinkles and fine lines, and enhance facial features. They are typically made of hyaluronic acid, a substance found naturally in the body that helps to maintain skin hydration and elasticity. 

When injected into the skin, dermal fillers can add volume and structure, reducing the appearance of wrinkles and restoring a more youthful look. They are commonly used to treat areas such as the cheeks, lips, nasolabial folds, and under-eye area.