What Is Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Relief?

The idea of using electricity to treat or distract from pain has been around since Roman times. But the first transcutaneous electrical nerve stimulation (TENS) unit, as we know it, was introduced in the 1970s. Advances in technology since then have made use of the device more popular and more widespread.

Here, we’ll discuss how TENS works for pain relief, when it might be useful, and how effective it is.

What is a TENS unit?

Transcutaneous electrical nerve stimulation (TENS) is a method of pain relief. It uses an electric current to soothe or distract from pain.

A TENS unit has a few components:

• Main device: This small, lightweight, programmable machine creates the electric current.

• Electrodes: These pads attach to your skin where you’re seeking pain relief. The pads have conducting gel. Or, in some cases, they require separate gel application. The gel facilitates electrical conduction.

• Wires: These connect the device to the electrodes.

A TENS unit delivers electrical energy in pulses. You can change the settings of the device to change the intensity, frequency, or duration of the pulses.

How is a TENS unit used for pain relief?

TENS can be helpful for both acute and chronic pain from many causes, including:

• Arthritis

• Neuropathy

• Back and neck pain

• Spinal cord injuries

• Fibromyalgia

• Tendon problems

Some advantages of TENS are that most people can use it, and it’s unlikely to harm you. TENS is noninvasive, and the electrodes stay away from major nerves or organs. There are certain situations or areas where you should avoid TENS (more below). But, generally, it’s pretty safe.

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• Getting relief may depend on how you advocate for yourself. Here’s how to talk with your healthcare team about your pain.

TENS therapy can be combined with other pain management techniques too. These can include, among others: 

• Acupuncture

• Physical therapy

• Chiropractic treatment

• Medications

• Injections

How does a TENS unit work?

Experts believe there are two main ways in which TENS works. The first involves the gate control theory of pain. According to this theory, impulses from non-painful sensations (like buzzing or tingling) travel faster to the brain than regular pain signals. So the faster signals from TENS can help to “close the gate” or prevent the slower pain signals from reaching the brain. In other words, your brain recognizes the sensations created by the TENS unit instead of pain.

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The second method of pain relief from TENS involves the endogenous opioid system. High-frequency TENS stimulates release of endorphins and other chemicals, which stimulate opioid receptors in the brain. Endorphins are thought of as your body’s “natural pain killers.”

While there are several types of TENS units, they all function on this same premise.

Is TENS therapy effective for pain?

Experts have debated for decades about how well TENS works for pain. This is mostly due to mixed results in studies, which often have different definitions of pain relief and include different diagnoses.

A recent review of 381 randomized controlled trials concluded that TENS provides pain relief during use and immediately after. This review included many different pain-causing conditions, but not many studies extended beyond a few months.

It’s important to note that your body can become less responsive to TENS with repeated use at the same settings. Studies suggest changing the frequency, intensity, and duration can help you get consistent results. You can also consider taking breaks and occasionally changing the placement of the electrode pads. Some evidence suggests that you can use a TENS unit for several years with good reduction in pain for that period, although the studies are limited.

At the end of the day, TENS doesn’t work for everyone. It’s difficult to predict how people will respond to it. But due to safety and accessibility, it’s worth a try for anyone interested in non-medicine forms of pain relief.

Important safety considerations

Be sure to read all of the device manufacturer’s instructions before using a TENS unit. Using caution while placing the electrodes on your body can help prevent injury.

There are a few situations in which you should avoid TENS therapy, including:

• Pregnancy

• Epilepsy or strong history of seizures

• Presence of a pacemaker or defibrillator

Certain areas of the body are more susceptible to injury from electric current than others. Avoid putting electrodes:

• Near the mouth or eyes

• On the neck

• On the chest

• On or near genitalia

Avoid TENS therapy near areas of the body with:

• Cancer

• Recent or current radiation treatment

• Skin wounds or infection 

• Certain skin problems, like eczema

• Numbness

• Deep venous thrombosis (DVT)

• Topical medicine patches

How do you use a TENS machine at home?

TENS units are designed to be light and portable, making them easy to use at home. That said, it’s best to see or at least contact a healthcare professional first. They can make sure it’s safe for you to use. They can also guide you on:

• How to use the device correctly

• Electrode placement

• The best settings for your condition

Be sure to read the instructions from the device manufacturer on placement of the electrode pads and safety precautions (as above). Doing so can help prevent injury and make sure you get the most out of TENS therapy. 

Where can you get a TENS unit?

You can get a TENS unit online or at your local pharmacy. But it helps to talk with a healthcare professional first, so you know what features to look for before buying.

Consider asking your healthcare team for a physical therapy referral, so you can try it before you buy it. You can also ask for a TENS prescription, if that would help in terms of insurance coverage.

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Written by:

Sudheer Potru, DO, FASAM

Sudheer Potru, DO, FASAM, is a triple-board-certified physician and writer for GoodRx. He has a decade of experience in perioperative and clinic medicine.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

Reviewed by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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