Neuromodulator injections can temporarily reduce moderate to severe frown lines between the brows, around the eyes and mouth by causing the weakening of targeted muscles. During treatment, very low doses of the neuromodulator are injected directly into the muscles that cause stubborn lines. Neuromodulators work by blocking the transmission of nerve impulses to the injected muscles; this reduces the activity of the muscles that cause those persistent lines to form. As the muscle weakens, the wrinkles in the skin gradually soften and often disappear, giving the face a more relaxed and refreshed look.