TENS therapy for pain relief

TENS Therapy for Pain Relief: Everything You Need to Know!

What is TENS therapy?

Transcutaneous electrical nerve stimulation (TENS) therapy is the most widely used type of electrotherapy for the management of both chronic and acute pain.

The therapy is administered through a TENS unit (a small battery-operated device) that has leads connected to sticky pads (electrodes), although wireless versions are becoming increasingly popular.

A mild electrical current is sent from the device to the pads, providing a drug-free treatment option for a number of conditions including back pain and labor pains.

Can TENS therapy provide pain relief?

Physicians and other healthcare professionals have been using TENS as a form of pain relief since the 1960s.

While there is conflicting information on the impact of TENS, there is a growing body of significant research that shows how powerful TENS can be for pain relief.

One of the biggest advantages is the fact that it’s a drug-free way to relieve pain.

TENS therapy is therefore ideal for those who can’t take prescribed pain medication, or choose not to due to the side effects.

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TENS is typically used in combination with other treatments to help manage pain.

Though not a cure, it can help you treat the root cause of the problem.

A fishy fact:

In 2500 BC stone carvings depicting Roman physicians using electric fish to treat conditions were discovered.

Confused About The Difference Between TENS And EMS?

Many people confuse TENS with electrical muscle stimulation (EMS). While TENS and EMS units can look almost identical, the two have completely different purposes so it’s imperative that you choose the correct type of device.


A TENS unit is designed to stimulate the nerves to help reduce both chronic and acute pain. However an EMS machine makes the muscles contract.

EMS therefore is more commonly used for muscle building, recovery, training, rehabilitation, injury prevention and cosmetic appearance.

You can purchase units that offer both functions, such as the one featured below:

What’s the cost of TENS therapy?

The initial cost involves the purchase of the machine, which typically includes the device, lead wires, pads (electrodes), and the first set of batteries or a charger (if it’s rechargeable, like most modern devices tend to be).

Over the counter (OTC) TENS units can be found for as little as $20 – and in some cases – perhaps even less.

More expensive devices can cost hundreds and even thousands of dollars.

However price doesn’t always equate to performance so it’s worth reading a few reviews before making a purchase.

In terms of maintenance, pads need replacing after a certain number of uses or when they wear out, and of course non-rechargeable devices need replacement batteries.

Did You Know?

In 1772, John Birch, an English surgeon, used electrical current to control pain. He later founded the Electrical Department at St Thomas’ Hospital, London.

Do you need a prescription to try TENS therapy?

Even though TENS machines can be purchased without a prescription (in many countries, like the USA, Canada, and UK), there are a few individuals who should not use them.

For this reason, it is best to first seek the advice of a medical professional (e.g. a doctor, physical therapist or chiropractor).

Medical sources and TENS manufacturers tend to list similar warnings about who should not use the devices.

However, they are very rarely identical, which is why you should always speak to a health professional.

As an example, the NHS website (the UK’s National Health Service) states that people with a pacemaker (or any other type of electrical or metal implant in their body) should seek medical advice before using a TENS unit.

It says the same for anyone who is pregnant, has epilepsy or a heart rhythm disorder.

Certain TENS manufacturers also advise that anyone who has recently undergone a surgical procedure, or has cancer or any other health condition should not use the unit without speaking to a physician.

So if you’re in any doubt about suitability it’s certainly worth checking before you begin.

Does TENS therapy have any side effects?

Most people who use TENS do so without experiencing any side effects.

However, in the past it was common that a very small number of users may have an allergic skin reaction to the pads (approximately 2-3%).

To counter this, manufacturers have moved to special latex-free pads. If you do have allergies, you should still always check the material of the pads before use.

Other side effects from a TENS unit are often down to people not following the guidance and overusing the device or having the intensity set too high.

Using the machine too much can make the area being treated sore.

While using excessive intensity can make muscles twitch and result in unpleasant sensations.

If you use the machine as advised by your physician and the manufacturer, it’s unlikely you’ll experience any side effects.

Frequently Asked Questions: TENS therapy FAQs

What does a TENS unit feel like?

What does a TENS unit feel like?

Small electric pulses give you a buzzing feeling on your skin, with some describing it as a tingling sensation.

How many channels and pads do I need?

How many channels and pads do I need?

A channel has two pads, and both are required for your TENS unit to work. This is because a positive charge is sent through one pad and a negative charge through the other.

Single channel machines can be used with two pads, and you don’t have the option to add more pads.

Most people opt for a dual channel TENS unit, meaning you can choose either two or four pads. It gives you the flexibility to treat two areas of your body at the same time.

Some devices (such as iReliev’s Wireless TENS + EMS Muscle Stimulator) even have four channels, known as quad channel, allowing eight pads so you can treat a larger area, or eight different pain points!

What is the difference between programs and modes?

What is the difference between programs and modes?

There isn’t actually a difference. Some manufacturers opt to use the term programs, whereas others use modes. They all generally refer to the same thing, a preset type of TENS therapy.

Should I buy a rechargeable device?

Should I buy a rechargeable device?

You’ll find that most modern TENS units are now rechargeable. They tend to be higher priced however over time they will probably cost less to run as you won’t need to replace the batteries.

Of course you do have to remember to charge your device, but with many portable power banks available on the market it can be a minor consideration.

Do I need independent intensity controls for each channel?

Do I need independent intensity controls for each channel?

Nearly all dual channel TENS machines have independent intensity controls for each channel. This allows you to increase and decrease the strength of your treatment on each individual channel.

It’s a great option when you’re treating two areas at the same time, as it might be that you need a strong intensity on just one area.

What are fully isolated channels?

What are fully isolated channels?

Essentially this means you can run separate programs on different channels, rather than just different intensities.

This feature can found in a selection of HealthmateForever’s machines, and is ideal if you have different types of pain.

In the example below the Acupuncture mode has been selected in channel 1, with an intensity level of 15.

While in channel 2, the Tapping mode is being run with the intensity set to level 8.

TENS FAQs – isolated channels with different modes in each channel

Do more intensity levels mean more power?

Do more intensity levels mean more power?

No. People tend to think the number of intensity levels reflect the power of the device, however this is a common misconception.

To put it simply, the intensity levels are the stages or increments that the machine can go through, like the volume control on your television.

If you have 10 intensity levels you’re going to be adjusting the power output by 10% each time. With 20 levels it’d be a 5%, 25 levels would be 4%.

Here’s a diagram to help explain:

TENS FAQs – 25, 20, and 10 intensity levels as percentages of power range

Is it better to have more intensity levels?

Is it better to have more intensity levels?

The more intensity levels you have, the greater your control over the power output.

With a higher number of levels you have more chance of finding the intensity that works best for you.

For example if you have a machine with 10 levels, level 7 might not feel powerful enough but level 8 might feel too strong.

However if you have 20 intensity levels, on a machine with the same power output, you’d effectively be able to get to level 7.5.

We’ve looked closely at devices, comparing features including intensity levels, to help you make your decision.

What conditions can a TENS machine be used for?

What conditions can a TENS machine be used for?

Research has shown TENS to be an effective treatment option for managing a wide range of different conditions, including:

  • Arthritis
  • Back pain
  • Fibromyalgia
  • Foot pain
  • Hip pain
  • Knee pain
  • Labor pain
  • Neck pain
  • Neuropathic pain
  • Sciatica
  • Shoulder pain
  • Sports injuries
  • Tennis elbow

How do I find out more about TENS units?

How do I find out more about TENS units?

We have a dedicated area of our site, to give you all the information you need.

If you have a question you would like answering, please use the comments section below.

So once you’ve done your research and found a device you like, it’s time to start reaping the benefits of TENS therapy!


  1. Nursing Times. (2012) Exploring the evidence for using TENS to relieve pain. [Online] Available from: https://www.nursingtimes.net/clinical-archive/pain-management/exploring-the-evidence-for-using-tens-to-relieve-pain-09-03-2012/ [Accessed 17 November 2019].
  2. Wikisource. (2012) Birch, John (1745?-1815) (DNB00). [Online] Available from: https://en.wikisource.org/wiki/Birch,_John_(1745%3F-1815)_(DNB00) [Accessed 17 November 2019].