Hyaluronic acid is the key molecule responsible for skin moisture. It helps cells to retain water and collagen, allowing for skin elasticity. Although the body naturally produces hyaluronic acid, as it ages, our cells do not have the same ability to retain sufficient water, degenerating the collagen and, thus, losing elasticity. Restylane offers a family of products, and our doctors will work with you to determine which Restylane product is right for you.