What is TENS? TENS, or Transcutaneous Electrical Nerve Stimulation, is a non-invasive, drug free method to control your pain by sending tiny electrical impulses through the skin. These impulses stimulate your nerves which send pain blocking signals to your brain. In many cases, this stimulation will greatly reduce or eliminate pain.TENS therapy is used to treat acute and chronic back pain, Sciatic Nerve Pain relief, muscular and disc syndromes, arthritis, shoulder pain, and many other painful conditions. More reading on how TENS works.