TENS, or transcutaneous electrical nerve stimulation, is a non-invasive, drug-free option for pain management. A TENS unit replaces pain signals with a side effect-free tingling or buzzing sensation that is controlled by the user. Although the TENS unit mechanism is fairly straightforward, there are some important things to keep in mind. Knowing how to use a TENS unit correctly is the key for long-lasting pain relief. Here’s answers to your most frequently-asked questions.

What is a TENS unit?

Transcutaneous electrical nerve stimulation (TENS) is a cell phone-sized unit with two wires attached to it. At the end of each wire is a self-sticking pad that you place on your body. A gentle electrical current moves through the wires and onto the pads. Patients place the pads on the area of their body with pain and active the electrical current with a button on the unit.

This simple device has been shown to relieve nerve pain without side effects and with no possibility of interaction with other treatments.

Research has established its potential effectiveness in the following conditions:

  • Neck pain
  • Lower back pain
  • Sciatica
  • Osteoarthritis and other forms of arthritis
  • Bursitis
  • Tendonitis
  • Cancer pain
  • Shoulder pain and frozen shoulder
  • Nerve pain
  • Migraines and headaches

There is also some indication that TENS may be helpful for people with diabetic neuropathy.

Most patients find that a 30-minute session with their TENS unit relieves pain for hours. Some might use their TENS unit during their daily activities that might otherwise cause them pain.

How does a TENS unit relieve pain?

For all of its effectiveness, doctors are not 100% sure how TENS unit therapy works. The battery-powered unit delivers a patient-controlled mild electrical current that is not strong enough to stimulate muscle movement but it likely does confuse the nerves.

This stimulation and confusion keeps the nerves too “busy” to send pain signals to the brain. The nerves focus instead on the immediate sensation of the electrical current – the mild buzzing from the TENS unit. Essentially, pain is replaced by a buzzing sensation that the brain remembers for hours after the stimulation occurs (instead of the pain).

Another way that a TENS unit likely works to relieve pain is by stimulating the production of endorphins. Endorphins are the body’s natural painkillers, the same substance responsible for a feeling of euphoria after exercise (also one of the reasons exercise is recommended for chronic pain).

Finally, the TENS unit can improve circulation in the area of its use (which promotes healing of injury) and also reduces or completely eliminates painful muscle spasms.

How to use a TENS unit

The first step in learning how to use a TENS unit is to talk to your doctor. They can help you decide if TENS unit therapy is a good treatment option for you and also help you to use the unit safely for best results.

General safety guidelines

In general, the electrical current delivered by a TENS unit is safe and does not pose a threat for electrical shock. There are some general safety guidelines to follow to reduce the risk of burns or other unrelated side effects, however.

Many patients find that using their TENS unit during daily exercise improves its effectiveness. Walking and other low impact exercise like riding a bike or hiking can be a great time to utilize this treatment.

Do not use a TENS unit in the bath or shower. This can damage the unit, and electricity around water is always a bad idea.

Keep your TENS unit patches for your own use. Do not share them, even to demonstrate what the buzzing sensation feels like on a non-painful part of someone else’s body.

Make sure the TENS unit is off when you are applying, removing, or otherwise relocating patches on your body.

Stop using your TENS unit and let your doctor know if you experience any of the following symptoms:

  • Headache
  • Nausea
  • Dizziness
  • Irritation of the skin

Finally, only use the TENS unit on yourself as instructed, and keep it away from children.


TENS unit electrode placement is of paramount importance. Proper placement of electrodes can make or break this therapy’s effectiveness.

Before you begin, make sure batteries are properly installed in the unit (or the unit is fully charged). Place the wire leads all the way into the electrode patches (no exposed metal), then plug the leads into the top of your TENS unit.

Skin should be clean, dry, and free of lotions, oils, or powders.

Electrodes should be placed directly on or very near the painful area. It is important to mix up where you place the electrodes to avoid potential skin irritation.

In order to make a complete circuit, you need to use either two or four patches. Changing the distance between these patches changes the amount of electricity that flows between them as well as the intensity of the current. Although the patches should be at least one inch apart, do note that the farther apart they are the less effective they will be.

Remember that the closer you are to the painful area, the exact spot of pain, the more effective this treatment will be.

Avoid these areas

The electrodes should not come in contact with any metal on the body (e.g., a belt or jewelry).

There are also some areas that should be avoided when considering TENS unit electrode placement. These include:

  • The eyes and the throat
  • On cuts or sores (and broken skin in general)
  • On a tumor
  • Directly on the spinal cord
  • Inside the body
  • Directly over bones


When you first use your TENS unit, your doctor will help determine which strength to set the electrical current.

You may find that your body gets used to it and the tingling or buzzing sensation decreases. When this occurs, you can ask your doctor if it’s okay to turn the strength up so that the sensation is present but still comfortable.

How long is it safe to use a TENS unit?

A TENS unit can be used as long as it is providing relief. As noted below, if pain relief begins to diminish, taking a break can help. This allows your nerves to relax a little and settle down. If pain returns after the break, you may find that your TENS unit helps to relieve it.

TENS units can also be used in conjunction with other treatments. Talk to your doctor about a coordinated treatment plan that includes a timeline for using your TENS unit.

Can I use my TENS unit while sleeping?

It may seem practical to use a TENS unit while sleeping, especially if your pain condition flares up at night, but this is not a good idea. The gentle buzz of the electrodes may turn into a skin irritant if they become pressed too firmly on the skin or one of the patches becomes detached.

It’s better to be fully awake and in control of your TENS unit to monitor any changes or sensations that might be different or unusual.

How often can you use a TENS unit?

You can use your TENS unit daily as long as it is providing relief. Some patients find that a 30-minute session provides relief all day, while others may need to use their unit every other hour or so. The best guideline for how often you can use a TENS unit is your comfort and pain relief.

Some patients find it helpful to take a break for three to five days periodically. If you find that your TENS unit has stopped being effective for pain relief, a short break may restore its effectiveness.

How do I care for my TENS unit?

There are several considerations when caring for and maintaining your TENS unit. After each use, the wire leads can be removed from the patches after the unit is turned off, but the patches can remain on the skin if you will use the unit again within a couple hours. If you want to remove the patches, peel them carefully off your skin and store them in their plastic liner. These patches will last longer if you use them on clean skin and store them properly after use.

Your TENS unit does need to be cleaned periodically. Makes sure it is turned off, then wipe with a moist, soft cloth. Do not use cleaners or abrasives on the unit. If you store the unit for a long time, remove the batteries and keep the unit and wire leads in a cool, dry place. Take care to not bend or crimp the lead wires.

Are there side effects or potential risks?

The only potentially common side effect of TENS unit therapy is the mild ting