Botox® Cosmetic is a prescription medicine that is injected into muscles and used to improve the look of moderate-to-severe frown lines between the brows and other areas of the face in people 18 to 65 years of age for a short period of time (usually 4-6 months, depending on the individual). It works by blocking nerve impulses to the injected muscles. This reduces muscle activity that causes moderate to severe lines to form between the brows.