Transcutaneous electrical nerve stimulation (TENS) is a treatment to relieve pain. TENS works by sending low-level electrical charges through your skin. These charges interfere with pain signals traveling to your brain. TENS may also change the way your brain responds to pain. Get the facts about this treatment to help you decide if it’s right for you: 1. TENS is easy to use. A TENS unit is a battery-operated, hand-held electric pulse generator. Some TENS units have two wires with pads, called electrodes, on the ends. The pads go on your skin, over the painful area. Other TENS units have these electrodes directly attached to the pulse generator, so no wires are needed. When the unit is turned on, you may feel a tingling sensation. Using the unit for 10 to 15 minutes may be enough to relieve pain. 2. TENS is safe to use, but you have to know how to use it. Unlike prescription drugs for pain, there's no danger of an overdose with TENS. It can cause skin irritation or burns, but this is rare. Otherwise, serious side effects are minimal. Many people can learn to use TENS safely at home. Where you put the unit and electrodes is important. The best positions are at the outer edges of where you feel pain. Finding just the right spots may take some time. Also, you want to turn the level of the pulse generator up high enough to feel tingling, but not enough to feel pain. 3. Not all TENS units are alike. The most common type of TENS uses electrode patches you place on your skin. There's also an acupuncture-like TENS. The current goes into your skin through tiny needles. Both types are painless. Talk with your doctor, physical therapist, or other pain management specialist about what type of TENS unit may be best for your specific need. 4. Some people may not be able to use TENS. You should not use TENS if you don't know the cause of your pain. You also might not be able to use TENS if you are pregnant, have epilepsy, have certain skin conditions, or use an electrical device like a pacemaker or defibrillator. 5. TENS may help treat many types of pain. TENS may help with either short-term pain or chronic pain. Studies support the use of TENS for both nerve and muscle pain. But it may work for other types of pain as well. This includes pain after surgery, headaches, neck or back problems, and arthritis. People have also used it for pain from whiplash, dental problems, and even childbirth. You may need to adjust the strength and frequency of the electrical charge. You can also change the amount of time you use TENS. It may take some trial and error to figure out how best to use it to ease your pain. 6. TENS may not work for your pain. TENS is not a guaranteed solution. Sometimes it doesn't help people. In fact, some studies found that TENS worked no better than a fake treatment—or placebo. It will take more and bigger studies to really know how well TENS works and what types of pain responds best to it. 7. TENS is a work in progress. New TENS units that use different types of electrical currents are being developed. There are new TENS units that work for specific areas of the body-- for example, the U.S. Food and Drug Administration (FDA) has approved one type of TENS for migraine headaches. If one type doesn’t work for you, it may be worth trying a different type.