Even though researchers disagree on its effectiveness for lower back pain, they consider transcutaneous electrical nerve stimulation (TENS) safe with a low risk of complications. Learn where to place TENS electrodes for this type of pain.

A TENS unit is a small machine that delivers electrical impulses through pads placed on a certain part of your body to reduce pain. It works by blocking pain signals from reaching your spinal cord and brain.

Experts think that the idea of TENS dates back almost 2,000 years, when the Roman doctor Scribonius Largus suggested “electrical fish” from the ocean may help with pain relief.

Nowadays, TENS is FDA approved to relieve:

  • chronic pain
  • pain after surgery or a sudden injury
  • temporary pain associated with sore and aching muscles from exercise and household or work activities
  • arthritis

Read on to learn more about how to use a TENS unit to potentially manage back pain.

TENS units come with two or four electrode pads that can stick to your skin. Place the pads around the area giving you pain.

If your unit has two pads, you can place one on either side of the painful area at least 1 inch apart. If both sides of your back bother you, you can place one pad on either side of your spine. For pain on one side, you can place both electrodes next to each on the same side of your spine.

If your unit has four pads, you can put one set just above and below the painful area.

TENS unit for lower back pain placementShare on Pinterest
Example placement of TENS machine pads to treat lower back pain.

Can I put a TENS unit directly on my spine?

It’s a good idea to avoid putting TENS pads directly on your spine. Other areas to avoid putting TENS pads on include:

  • the front or sides of your neck
  • the sides of your head
  • near your eyes or mouth
  • numb areas
  • varicose veins
  • skin with an infection or irritation
  • your chest and upper back at the same time

It’s a good idea to consult a medical professional before using TENS at home to see if it’s potentially effective for your condition and learn how to use it best.

Here’s a general idea of using a TENS unit at home for lower back pain. For lower back pain treatment, you’ll likely need help from another person to place the pads and attach the electrode wires to the pads before treatment.

  1. Cleanse the pad placement area with water or rubbing alcohol and let it air dry.
  2. Place the pads on your skin at least 1 inch apart with the machine turned off.
  3. Attach the electrode wires to the electrode pads and the TENS unit.
  4. Turn on the TENS unit and set it to the desired frequency and intensity. Usually, experts use a frequency between 50 hertz (Hz) to 150 Hz to treat pain. You can increase the intensity to the point when you feel a strong but comfortable sensation. Turning the intensity down is a good idea if you feel pain or discomfort.
  5. Run the machine for the duration of your treatment. Usually, treatment is between 15 to 60 minutes. If you’re unsure how long to run it, 30 to 45 minutes is a good starting place.
  6. Turn the machine off and remove the electrode pads.

Unlike many medications, TENS is free of the risk of overdose. You can use it as needed to provide pain relief throughout the day. Many experts recommend applying it up to four times daily.

Experts generally consider TENS safe with a low risk of side effects. Some people experience skin irritation in the pad placement areas. Some people experience burns at the electrode sites, but this is rare.

Get medical advice before using TENS if you:

Disagreement remains in scientific communities over which types of pain and conditions TENS may effectively treat.

In a 2021 research review, researchers looked at the effectiveness of TENS for sudden or chronic pain. Here’s a summary of the conclusions of the studies.

  • TENS offered some benefit in 69 studies.
  • TENS offered no benefit in 13 studies.
  • TENS had inconclusive evidence to support its use in 87 studies.

What types of back pain does TENS treat?

Experts use TENS to treat many types of lower back pain, including:

  • nonspecific back pain
  • sudden muscular strains
  • chronic back pain
  • postsurgical pain
  • labor pain

You don’t need a prescription to buy a TENS machine, but it’s unlikely that your insurance will cover the cost. It may cover a TENS machine in certain situations. For example, Medicare can cover TENS for postsurgical pain.

Prices of TENS units start under $25 and can be more than $150. You can buy them at many pharmacies, big-box stores, and online.

TENS uses electricity to block pain signals to your spinal cord and brain and treat pain. TENS may provide you with relief from back pain, but there is mixed research on its effectiveness.

You can buy a TENS unit without a prescription, but it’s still a good idea to consult a medical expert to learn how to use it best. They can help you learn exactly where to place the pads and which settings to use.