Deep Heat can be used to generate heat in tired, injured or sore muscles. As it is absorbed, your body’s natural enzymes turn its special blend of ingredients into a powerful painkiller. How are heat patches different? A ‘topical’ treatment is one that is applied directly to the part of the body where you feel the discomfort. This is different to painkillers taken by mouth, which dissolve to release their ingredients into the bloodstream and throughout the body. Topical analgesics minimise the risk of side effects by delivering the drug to the area of application. They can also be an effective alternative to oral analgesics, or can be used in conjunction with oral analgesics if necessary.