TENS Unit vs EMS Unit : What Is the Difference?

tens vs ems

Up to one-third of all Americans may suffer from chronic pain. Many incurable conditions are the result of chronic pain and the nerves themselves are the source of the pain rather than any damaged tissue that may surround them. In addition to the debilitating physical effects of chronic pain, many of its sufferers experience depression as well; they feel their situation to be hopeless and feel doomed to suffer throughout their remaining lifetimes.

Two electrical devices, the TENS unit, or Transcutaneous Electrical Nerve Stimulator, and the EMS unit, or Electronic Muscle Stimulator, can be used to treat chronic pain. While the units function similarly, simply put, their names indicate their applications. A TENS unit stimulates the nerve endings while the EMS unit stimulates the muscles.

Amazingly enough, electrical stimulation of the nerves dates back to ancient Rome when the court physician to Claudius reported that standing on an electrical fish would ease pain, at least for the human. Centuries later, Benjamin Franklin advocated the use of electrical stimulation to reduce pain, which he accomplished through use of his electreat device.  Franklin reasoned that since two objects cannot simultaneously occupy the same space, forcing electrical impulses into the body would force the pain to leave.

Despite his flawed hypothesis, Franklin’s electreat device was the forefather of today’s modern methods, which include use of a TENS unit to electrically stimulate the nerve endings to reduce pain. TENS uses both high frequency impulses and low frequency impulses to stimulate the nerve endings and there has been some indication that the higher frequency impulses are more efficacious in treatment of some forms of osteoarthritis. However, there is a lack of sufficient quantifiable data to document the effectiveness of a TENS unit to alleviate chronic pain, whether through use of low frequency or high frequency.

The National Institute of Health approved a study to determine the efficacy of TENS as a treatment for chronic pain but as yet, no recruitments have been made for study participants. One objective of this study is to determine why the TENS treatment is more efficacious on some chronic pain sufferers than it is on others.


A microcurrent TENS unit is available that uses microcurrent to increase the production of ATP, which is adenosine triphosphate and the substance that supplies energy to the body on a cellular level. Using currents of 50uA up to 1000 uA, ATP production increased fivefold. This translates to decreased healing time as well as increased pain reduction, including chronic pain. Although lasting pain reduction may require regular microcurrent sessions, in some individuals the pain reduction begins to last longer and the time between sessions lengthens. This may be due to the increased circulatory action that enables the lymph system to begin clearing the body of accumulated toxins. The sensations of both the microcurrent and conventional TENS treatments are more like tingling sensations than the unpleasant feeling of a small electrical shock.

Although both the TENS and the EMS units transmit electrical signals, the EMS focuses on the muscle rather than the nerve ending. EMS uses a cycle of stimulation, contraction and then relaxation at intensities from 1 to 130Mh to increase blood flow to the area, which decreases inflammation and promotes healing and muscle growth. By stimulating the muscles at their basic structure, an EMS unit causes muscle contractions similar to those obtained by exercise. The EMS units are specifically used to prevent atrophied muscles or for retraining muscles, such as in an individual who has been paralyzed or partially paralyzed. In addition, EMS is used for many other applications such as range of motion improvement, increased circulatory action and the prevention of blood clots.

The Best of Both Worlds

Some chronic pain sufferers have found that using a combination of both TENS and EMS provides maximum results. Dual units are available for that purpose and the combination of pain reduction and muscle stimulation at the cellular level provides them with increased muscle tone and decreased levels of chronic pain. However, use of these devices should be monitored by a professional so that the electrodes are properly placed and the proper signal is used. Electrode placement should vary with each treatment and those who are pregnant, have seizures or have a pacemaker should not use either EMS or TENS without the specific advice of their physician.

Back to the top

Recent Posts