What You Should Know About Non-Prescription TENS Units


Marijke Vroomen Durning, RN

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Over 100 million people in the United States live with some sort of chronic pain, and countless more experience acute pain, pain that usually goes away within a few weeks. Drug store aisles are lined with over-the-counter pain relievers, and prescriptions for pain medications are rising. But these drugs can have drawbacks, such as side effects or, in the case of opioids, possible addiction. As a result many people are turning to alternative methods of pain control, such as transcutaneous electrical nerve stimulation, or TENS.

What Is TENS?

TENS is a non-invasive, non-medicinal treatment that uses mild electric currents to interrupt the pain messages sent to your brain. It’s also believed that the currents may help your body release its own natural pain killers, called endorphins. When the TENS unit is turned on, a current flows between two electrodes placed on either side of the painful area. The current can vary in strength and pattern according to the setting you choose. The treatment usually lasts from five to 15 minutes, sometimes longer.

Originally, TENS units were large and bulky for use in hospitals and clinics. But technology has made these machines portable and affordable, and available to the general public.

How TENS Units May Help You

There have been many clinical trials that have looked at how effective TENS units are in providing pain relief. Researchers have even tested TENS on pain from labor and delivery. The pain relief is short-term and people who use TENS often use it several times a day. Types of pain TENS may help relieve include:

  • Diabetic neuropathy: Painful nerve endings, often in the feet, that can be a complication of diabetes

  • Arthritis

  • Post-operative pain

  • Phantom pain, pain that the body feels after a limb has been amputated

While TENS does help some people with acute pain, it’s usually most effective for chronic pain. Also, TENS doesn’t treat the actual cause of pain, so you may still undergo other treatments or therapy to treat the source. Be sure to talk to your doctor before treating with a TENS unit on your own.

TENS Units at Home

TENS treatment is generally safe but as with most therapies, there are some ways the treatment shouldn’t be used and some people who should not use it. The electrodes for a TENS unit should not be placed:

  • Near their heart or so the current goes through your chest, from front to back

  • On your face

  • On your neck, particularly near the carotid arteries, just below your ears

  • On broken or irritated skin

  • Around varicose veins

  • On parts of the body that are numb, unless advised by your doctor

People who should not use a TENS machine without their doctor’s approval include those who:

  • Have a pacemaker

  • Have heart disease

  • Have epilepsy

  • Are pregnant

Buying a Portable TENS Unit

A portable TENS unit is battery operated and usually small enough to put in your purse or clip onto your belt. Along with the unit itself, there are wires and electrodes connected to disposable adhesive pads. Your unit may come with pads in various sizes, for use on different parts of the body. For example, if you are using TENS on your forearm, you need small pads, but you need larger ones if the treatment is for your hip or back. The adhesive pads do lose their stickiness after a while, so when you are purchasing a unit, be sure you can buy replacements.

If you’re buying a unit based on your doctor or physical therapist’s suggestion, ask if they recommend a specific type and why. When deciding which one to buy, check out the unit in person if possible, so you can verify that you can easily see and read the screen, and that the buttons or controls are easy to manage. You can also check the length of the wires – many units come with two lengths. Longer wires are important if you are using the unit on the lower part of your body or back.

Using a TENS Unit

TENS units are easy to use. Place the electrode pads on either side of the painful area, attach the wires to the pads, and turn on the unit. However, before starting treatment, speak with your doctor or physical therapist about how to tailor your treatment to fit your needs. Here are some questions you might ask:

  • Where do I place the electrodes?

  • How long should I leave the TENS current on?

  • How strong should the current be?

  • Should I set a steady current or should it pulsate?

  • Are there any signs I should watch for that warn me that I should stop the treatment?

  • How often should I use the TENS unit?

  • How long can I continue to use the TENS unit?

Each unit comes with instructions. Be sure to you read and understand them in order to get the most effective treatment and to protect yourself from injury. The instructions will remind you not to use the machine while operating heavy machinery nor while you are bathing or in the shower.

As with all treatments for pain, TENS doesn’t help everyone. But if a TENS unit can help relieve your pain, it may be well worth the investment.


5 Tips for Purchasing a TENS Unit

Because there are several types of TENS units available for purchase, it helps to do some research before purchasing one.
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Medical Reviewers: William C. Lloyd III, MD, FACS Last Review Date: May 6, 2016

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Medical References

  1. AAPM Facts and Figures on Pain. The American Academy of Pain Medicine. http://www.painmed.org/patientcenter/facts_on_pain.aspx#incidence
  2. TENS Indications. Open Anesthesia. https://www.openanesthesia.org/tens_indications/
  3. Transcutaneous Electrical Nerve Stimulation. Medscape. http://emedicine.medscape.com/article/325107-overview#showall
  4. Cipriano G, de Camargo Carvalho AC, Bernardelli GF, Tayar Peres PA. Short-term transcutaneous electrical nerve stimulation after cardiac surgery: effect on pain, pulmonary function and electrical muscle activity. Interact Cardiovasc Thorac Surg. 2008 Aug;7(4):539-43. doi: 10.1510/icvts.2007.168542. Epub 2008 Apr 16. http://www.ncbi.nlm.nih.gov/pubmed/18417519

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