Transcutaneous Electrical Nerve Stimulation, or “TENS”, is an popular drug-free method of pain relief. Sticky pads transmit battery-powered electrical pulses into the skin via wires connected to a small control box. These small electric shocks can help to provide relief for sufferers of certain forms of pain.

In this article, we will be investigating Transcutaneous Electrical Nerve Stimulation in depth to help you decide if this could be a good choice of pain relief for you.

What Is Transcutaneous Electrical Nerve Stimulation?

Why Do People Use TENS?

TENS units are used as form of convenient, portable, and noninvasive pain relief that can be used at home. They can be used to combat many different kinds of pain such as:

  • Lower back pain
  • Tendonitis
  • Shoulder pain
  • Neck pain
  • Sciatica
  • Frozen shoulder
  • Migraines
  • Arthritis
  • Cancer-related pain
  • Childbirth
  • Bursitis
  • Diabetic neuropathy

TENS is effectively used in the management and relief of many types of pain.

Numerous clinical trials have proven the effectiveness of the TENS method. Below are some examples of relevant research supporting TENS pain relief for osteoarthritis and musculoskeletal pain.

Clinical Evidence – Use of TENS for Osteoarthritis Pain

Osteoarthritis is a common and painful degenerative condition that affects the joints. There is no cure, so, management of pain is an ongoing process in sufferers.

Studies have shown that using TENS devices in combination with hyaluronic acid injections resulted in significant pain relief for those individuals who struggle with osteoarthritis. In fact, pain relief increased over the first months of use and was still apparent six months later.

Clinical Evidence – Use of TENS for Head, Neck, and Shoulder Pain

One of the most widely suffered categories of pain are headaches and musculoskeletal pain in the neck and shoulder. A particularly common issue affecting the shoulder is a condition known as adhesive capsulitis or “frozen shoulder”, which intensely limits the range of motion allowed by the joint.

TENS therapy has demonstrated an ability to increase range of motion to a greater degree than that achieved by exercise, manual manipulation, and heat treatment.

Furthermore, TENS therapy has been shown to effectively treat and prevent migraines, so much so that the use of medication was markedly reduced.

Can Everyone Use TENS?

TENS machines are most often used in the treatment of muscle, joint and nerve pain. There are almost no side effects from the use of TENS machines, but there are some people who should not use TENS machines, especially without prior discussion with a medical professional:

  • Those who are pregnant
  • Those with pacemakers
  • People who have heart disease
  • Anyone who does not know the cause of their pain

How Does TENS Work?

holding the forearm of a man in the therapy seasion

TENS machines use a variety of settings that differ in their intensity. Voltage and the duration of each electrical pulse can be adjusted to best treat both the type and the location of the pain being suffered.

Electrical current is transmitted through the electrode pads and into the skin, creating a tingling sensation as it stimulates the nerves beneath. It is this nerve stimulation that serves to reduce the perception of pain. The actual mechanism of action within the body is subject to two different theories; “Gate Control Theory” and “The Endorphin Release” theory.

Gate Control Theory centers upon the suggestion that there is a nerve mechanism in the spinal cord, which can behave like a gate, either opening up or blocking the route of signals from the body to the brain. It is the type of signal that determines whether this ‘gate’ is open, partially closed, or fully closed. Therefore determining how much pain is actively perceived in the body. It is thought that the pulses from the TENS machine keep the nerves “busy”, interfering with the movement of pain signals in the spinal cord and blocking their journey to the brain.

The Endorphin Release Theory suggests that the electrical pulses result in the release of endorphins and morphine-like compounds in the body. These substances are powerful natural pain relievers which work by blocking pain signals to the brain.

How Do I Use TENS?

Transcutaneous Electrical Nerve Stimulation

Tens machines can be used at home without medical supervision. The user is in control of the settings, able to adjust them at will in accordance with their level of pain. In most cases, the TENS machine is used for around 15 to 45 minutes at a time, multiple times throughout the day. TENS machines are designed to be portable. They are often clipped on to a belt or pocket so the user can get on with their day while benefiting from continued pain relief.

Patients may use the TENS machine alone, or in combination with medication. In some cases, the use of a TENS machine can result in a reduction of the amount of pain relief drugs that are required by the sufferer. There is almost always a period of trial and error when first using a TENS machine in order to determine the most appropriate setting for the individual user.

All TENS machines will have slightly differing instructions depending upon the model and manufacturer. However, general advice for use is similar to the following: 

  • Ensure your skin is clean, dry, and unbroken before use.
  • Before placing electrode pads onto skin, test that the machine is working by holding pads between fingers and turning unit on. It should feel tingly if working correctly.
  • Stick the pads on each side of the source of pain, leaving at least a 1 inch gap between them.
  • If you are going to be walking or moving the area, you can fix the pads down with tape.
  • Set the pulse rate low and then turn the machine on. Gradually increase the pulse rate until you feel a strong, but comfortable tingling.
  • It is normal for this sensation to diminish after a period of use. You may increase the pulse rate again until you return to the level of sensation you experienced before. Do not increase to the level of muscle twitching; this is too high.
  • Continue use for as long as advised in the directions.
  • When finished, you should remove the pads gently and clean both the pads and skin as directed before using again.

Of course, TENS machines may not be suitable for all pain and health conditions. Even though they are safe to use at home without supervision, you should always consult a physician before starting to use one. In some cases, you may be advised to try different medications first depending upon your type of pain.

Are there any Risks When Using TENS?

In contrast to prescription or over-the-counter counter medications, TENS pain relief is almost completely risk-free. The electrical current used is very low and does not penetrate the body tissues very far, presenting no risk to the majority of people.

That said, individuals with pacemakers or serious heart conditions shouldn’t use a TENS machine without discussing the matter with their physician first. The same applies to pregnant women. It is not advised to use a TENS machine while sleeping to avoid irritation, and to use adequate caution if using a machine while driving or using heavy machinery.

Furthermore, do not use a TENS unit:

  • Over your eyes, throat, spinal cord, or over a tumor.
  • Upon broken or irritated skin
  • With one pad on the front and one behind (through) the chest
  • Anywhere inside the body 

Overall, TENS machines are a low-risk pain relief option that should always be used in response to advice from a physician.


TENS machines are a form of pain relief therapy that help to manage discomfort and improve the sufferer’s quality of life. They cannot treat the cause of the pain, but can certainly make life more comfortable for those who are struggling with it. In some cases, TENS machines can be used as a complement to other pain relief medication and beneficial lifestyle changes.

Because TENS therapy is almost completely risk-free and easy to use alongside other treatments, it is a very convenient pain relief option for a large number of the population. If conventional pain relief hasn’t worked for you, TENS therapy could certainly be worth a try.

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