Heat therapy is recommended by health care professionals for muscular pain and stiffness. These patches are long lasting, odourless, drug free, and provide warming pain relief to help get you through the day. They work by penetrating heat to help relax stiff, sore, aching muscles and joints. The heat also increases blood flow to the affected area. These patches can be used to treat muscular pains, strains and joint stiffness for back, hip, thigh, calf, arm, neck and shoulder pain.