Wrinkles result from a combination of many factors. It's not just about cellular changes, collagen depletion, or damage caused by free radicals. When you frown or concentrate, the muscles between your brows contract, causing your skin to furrow and fold. When you squint, the muscles around your eyes contract and cause crow's feet. Neurotoxins are a prescription medicine that are injected into muscles and used to temporarily improve, reduce or eliminate the look of both moderate to severe frown lines and wrinkles, resulting in a refreshed, rested more youthful look.