Home / Pain Management / TENS FAQs: The Ultimate Guide

TENS FAQs: The Ultimate Guide

The Good Body’s most frequently asked questions about TENS devices, features, and requirements. To view the full list of FAQs click on the table of contents below.

How much does a TENS unit cost?

How much does a TENS unit cost?

You can find highly-rated entry-level TENS units for close to $20 these days. At the top end of the market, devices for home use can cost hundreds of dollars.

Machines with higher specifications and feature-sets generally command greater prices. To view and compare some of the most highly-rated TENS machines: check out this page.

Are TENS and EMS the same?

Are TENS and EMS the same?

While the devices may look similar, TENS and EMS are not the same.

A TENS unit stimulates the nerves, it is intended – and administered – to reduce both chronic and acute pain.

Whereas, an EMS machine makes the muscles contract. Common uses for EMS include: recovery, training, rehabilitation, prevention, and cosmetic appearance.

For a more detailed explanation, read our article about the differences between TENS and EMS.

You can find further resources on the site by clicking on the buttons below:

TENS posts
EMS posts

How many channels and pads do I need?

How many channels and pads do I need?

The most common choice is a dual channel TENS unit, you can use either two or four pads at a time with one of these devices.

Single channel machines can only be used with two pads, you cannot add more pads or channels to the setup.

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

The major advantage with a dual channel device is that you can treat two areas (or sides of the body) simultaneously. With a single channel unit you are limited to one area.

Some devices on the market today even have four channels (also known as quad channel). You can use up to eight pads at once with this kind of machine.

number of pads for single, dual, and quad channel TENS units

As a general rule, more channels and more pads will enable you to treat larger areas simultaneously. For example: with a quad channel machine you could use the eight pads to cover a substantial area of your back.

For most, a dual channel device is sufficient.

For more on pads: read this guide.

What is the difference between programs and modes?

What is the difference between programs and modes?

There isn’t really a difference. Some manufacturers like to use the term programs, whereas others use modes. Generally, they refer to the same thing, a preset type of TENS therapy.

Should I buy a rechargeable device?

Should I buy a rechargeable device?

This is down to personal preference and available spend. A rechargeable machine is likely to command a greater initial investment but it’ll probably cost less to run over time.

rechargeable device vs battery powered

The main argument for rechargeable TENS units is that you don’t have ongoing replacement battery costs. Nor do you have to fiddle about with the machine and swap the old set for new ones.

However, there are some counter-arguments to consider:

Firstly, you need to remember to charge the device. Unlike a standard battery powered machine, you can’t just swap it when it’s out of juice.

And although some units can be used while they’re being charged, you’re going to have to be close to the power outlet to do that.

Not only is that inconvenient, it’s rather messy – and when you factor in the machine’s lead wires (with the pads on) – you’re going to have cables all over the place.

With a device that takes standard batteries, so long as you keep spares – you’re going to be able to use it – pretty much straight away.

Another scenario to think about is if you’re going to be taking your unit away with you. This may be on business trips, vacation, days out, etc.

You may not always be in a situation where you can charge the machine. If your device takes standard batteries, you can take spares with you. And if you’re ever in the position where you run out of batteries, the likelihood is you’ll be able to get hold of some.

Similarly to the last point, if you were away from home and forgot to pack your charger, you could be in a predicament. Whereas, if you forgot to take batteries it would be something you could deal with.

Flipping this back round again for a final point, and it’s a pro rechargeable one. Imagine you were to get home from work, as an example, exhausted and ready for a TENS session.

If you had a battery powered device and realized you had run out of replacements, you’d have to go out and fetch some. Otherwise, you wouldn’t be able to use your machine. With a rechargeable one, you’d simply put it on charge for a little while and then be able to use it.

There are certainly plenty of advantages and disadvantages to either setup, it’s up to you to weight them up and decide which one suits you best.

Do I need independent intensity controls for each channel?

Do I need independent intensity controls for each channel?

Nearly all dual channel TENS machines on the market today have independent intensity controls for each channel. What this means is you can increase and decrease the treatment strength separately within the channels.

TENS FAQs – different intensity levels in each channel

This is a highly desirable feature because if you’re treating two areas at the same time it may be that you require a stronger intensity for one.

What are fully isolated channels?

What are isolated channels?

Fully isolated channels enable you to run separate programs in different channels, rather than just control the intensity for the channel. This is a quite a recent development and can be found in a selection of HealthmateForever’s machines, you can read about them here.

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

Does more intensity levels = more power?

Does more intensity levels = more power?

No. This is a common misconception.

People often think the number of intensity levels reflects how powerful the device is. This is incorrect.

Quite simply, the intensity levels are the increments (stages) in which the machine goes through the power range. Think of them like volume controls on a stereo or television.

If you have 10 intensity levels you’re going to be adjusting the power output (up or down) by 10% each time. With 20 levels it’d be a 5% per increase / decrease. 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 more intensity levels better?

Is more intensity levels better?

The more levels at your disposal – the greater control you have over the power output.

For example: you have a machine with 10 levels and the seventh one doesn’t quite feel powerful enough, but the eighth is too strong for you.

If that device had 20 intensity levels, for every level that machine with 10 has, you’d have two.

So in the example given, it may be that level 15 (on the machine with 20) is just right for your particular pain. Where 7 and 8 (on the device with 10) weren’t quite right.

TENS FAQs – more intensity levels = greater control

Levels 7 and 8 would represent 70% and 80% of the maximum power output – respectively – on the machine with 10 intensity levels, whereas level 15 on the device with 20 would be 75% of the full power range.

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

We actually created a resource that allows you to compare TENS machines by features and specification (including the number of intensity levels), it can be found on this page.

What is a TENS machine used to treat?

What is a TENS machine used to treat?

Physical therapists, chiropractors, and other healthcare professionals may choose to administer and prescribe TENS for a range of chronic and acute pains.

Some of the most common conditions and complaints include:

  • arthritis
  • back pain
  • fibromyalgia
  • foot pain
  • hip pain
  • knee pain
  • labor pain
  • neck pain
  • neuropathic pain
  • sciatica
  • shoulder pain
  • sports injuries
  • tennis elbow

Do I need a prescription for a TENS unit?

Do I need a prescription for a TENS unit?

TENS machines are readily available over the counter (OTC) in advice number of countries (including the USA, Canada, and the UK). This means they can actually be purchased without a prescription. However, many experts such as Dr Mary Harding recommend speaking to somebody first:

It is best to use a TENS machine only on the advice of a doctor or other health professional.

How do I submit a question?

How do I submit a question?

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

Check Also

Yoga Poses for Flexibility

The 10 Best Yoga Poses for Flexibility: Asanas to Make You More Flexible

The latest statistics show that improving flexibility is the most popular reason for starting yoga, …


  1. What are the A and B letters on the ultimate otc?

  2. I didn’t know you could get some of these systems over the counter. I had these used when I was in physical therapy recovering from a broken collarbone. I really think they make a difference. I noticed it helped relax the muscle and break up scar tissue.

Leave a Reply

Your email address will not be published. Required fields are marked *