A TENS machine is a small, portable device that uses gentle electrical pulses to help ease pain without medication. TENS stands for Transcutaneous Electrical Nerve Stimulation. The pulses pass through electrode pads placed on the skin near the area you want to treat, and you control the strength yourself. Many people use a TENS machine for back pain, joint pain, muscle tension, period pain and other everyday or persistent aches, at home, at work or on the move.

Most people now choose a wireless TENS machine for the freedom it gives, and the guides below explain how TENS works, where to put the pads, which settings to use and how to pick the right model. Still weighing it up? Start with our honest look at the pros and cons of a TENS machine.

How does a TENS machine work?

A TENS machine sends small electrical pulses through the pads into the nerves just below the skin. Most people describe it as a light tingling or buzzing. You turn it up or down until it feels clear but comfortable.

There are two main ways it is thought to help, and the settings decide which one you are using. On higher-frequency settings, the pulses stimulate the sensory nerves and can reduce how strongly pain signals reach the brain. This is usually explained by the gate control theory of pain, first set out by Ronald Melzack and Patrick Wall in 1965: busy touch nerves effectively crowd the "gate", so fewer pain messages get through. On lower-frequency settings, the stimulation is linked to the release of endorphins, the body's own natural pain-relieving chemicals.

TENS gives temporary relief and it does not work for everyone. It is best thought of as one drug-free tool within a wider pain-management routine, used alongside any treatment or medication you have been advised to take.

TENS machines for pain relief: what can you use one for?

A TENS machine is commonly used for aches and pains in the back, neck, shoulders, knees and other joints and muscles. Many people also use one for pain linked to sciatica, arthritis, sports injuries and period pain. What suits you depends on your situation and any advice you have been given. Our condition guides explain how TENS is typically used for each area, including pad placement tips:

Which TENS machine is best for you?

The right machine depends on what you are treating, how many areas you want to cover and how you want to use it day to day. Here is how our range matches up to the most common needs.

For lower back pain and sciatica

Back pain and sciatica often cover more than one area, so extra channels help. The Med-Fit Wireless 4 Channel TENS & EMS Machine lets you treat the lower back and leg in one session with no leads getting in the way. If you would rather keep things simple, the wired Med-Fit 1 Dual Channel TENS Machine is a dependable, budget-friendly option. Read our guides to TENS for lower back pain and TENS for sciatica for placement advice.

For treating two areas at once

Dual channel machines are a popular all-round choice. The Med-Fit Wireless 2 Channel TENS & EMS Machine treats up to two areas at the same time, so you can cover both knees, both shoulders or the neck and upper back in one session. See the full range of dual channel wireless TENS machines.

For period pain

The Fem-Ova Period Pain Relief machine is designed specifically for period pain and combines TENS with heat. Our guides to TENS for period pain and TENS for endometriosis explain how it is used.

For TENS, EMS and massage in one

If you want pain relief, muscle stimulation and massage programmes in one wireless, remote-controlled system, the Combo 2: TENS, EMS & Massage Machine treats up to two areas at once. For wider coverage, the Combo 4: TENS, EMS & Massage Machine treats up to four areas, and the single channel Combo 1 is the simplest way into the range.

For a first wireless TENS machine

New to TENS and want to try wireless without over-committing? The Painless TENS & EMS Machine is a single channel, rechargeable wireless unit with a remote. It treats one area at a time and is easy to get to grips with.

For sensitive skin

If standard pads tend to irritate your skin, choose a machine supplied with sensitive skin electrodes, such as the Wireless 2 Channel TENS & EMS Machine with Sensitive Skin Electrodes or the Painless TENS & EMS Machine with Sensitive Skin Electrodes.

For muscle recovery as well as pain

The Premier Pro TENS & EMS Machine is a rechargeable, dual channel wired unit that combines TENS with muscle stimulation programmes for conditioning and recovery. The 4 Channel TENS & EMS Machine is a wired, battery-powered option with four channels and a wide choice of preset programmes.

Wireless or wired: which should you choose?

Both types work in the same way, sending pulses through pads on the skin, so neither is inherently better at easing pain. The difference is how you use them.

A wireless TENS machine puts the pulse unit directly on the pad. You control it with a small remote. With no trailing leads you can move freely, reach awkward spots like the mid-back, and wear it discreetly under clothes at work or out and about. Most wireless models are rechargeable, so there are no batteries to keep buying.

A wired TENS machine has a small handheld unit connected to the pads by thin leads. It is simple, dependable and usually the most affordable way into TENS, and some people like having the controls in their hand. The trade-off is the leads, which can show under clothing and limit how freely you move. Browse our dual channel wired TENS machines.

	Wireless TENS	Wired TENS
Freedom of movement	Full, no trailing cables	Limited by the leads
Wearing under clothes	Discreet and easy to hide	Possible, but wires can show
Hard-to-reach areas	Easy to position and forget about	Fine with help placing the pads
Power	Usually rechargeable	Batteries or rechargeable, by model
Use during daily activity	Ideal, wear it and get on with your day	Better suited to sitting still
Cost	A little higher for the convenience	Lower, budget entry point

Single, dual or four channel?

Channels decide how many areas you can treat at once. Single channel treats one area and is the simplest option. Dual channel treats two areas and suits most people. Four channel gives the widest coverage for several sites in one session.

TENS vs EMS: what is the difference?

Many of our machines do both, so it helps to know which is which. TENS targets your nerves to help manage pain. EMS, or Electrical Muscle Stimulation, targets the muscles and makes them contract, which is used for conditioning, toning and recovery. A combined TENS and EMS machine lets you switch between the two as you need.

For the full breakdown, read What's the difference between EMS and TENS? If muscle work is your main goal, see our pick of EMS machines for muscle recovery and what EMS and TENS can and cannot do for your abs.

How to use a TENS machine

Here is the short version. For wired and wireless walkthroughs, pad care and troubleshooting, read our full guide on how to use a TENS machine.

Read the manual that came with your machine and check TENS is suitable for you.
Clean and dry the skin where the pads will go. Avoid creams or oils.
Stick the pads on or around the painful area, leaving a gap so they never touch.
With the machine switched off, connect the pads, then switch on and choose a programme.
Turn the intensity up slowly until the tingling feels clear but comfortable.
When the session ends, switch off before removing the pads, then put the pads back on their backing sheet so they keep their stick.

Where to put TENS pads

Pad placement makes a real difference. It often takes a few tries to find the spot that works best for you.

Place the pads on clean, dry skin on or around the painful area.
Leave a gap between the pads so they never touch.
For back pain, pads usually go either side of the spine rather than on it.
For larger areas such as the lower back, many people use four pads in a square or criss-cross pattern so the current crosses the sore area.
Never place pads on the neck, on the head or near the eyes or mouth, across the chest or around the heart, or over broken, irritated, infected or numb skin. Don't use pads on your chest and back at the same time.
Move the pads slightly between sessions to give your skin a break.

For sciatica, many people place one pair of pads on the lower back and a second pair along the path of the pain in the buttock or back of the leg. Our TENS for sciatica guide covers this in more detail.

Our condition guides, including TENS for neck pain, TENS for knee pain and TENS for shoulder pain, include area-specific placement tips.

TENS settings, frequency and how long to use it

Start every session on the lowest intensity and turn it up slowly until the tingling feels clear but still comfortable. It should never feel painful. If it becomes uncomfortable, turn it down.

Most machines come with preset programmes, which are the easiest place to start. As an example, our Med-Fit 1 manual describes conventional (high-frequency) TENS as 60Hz or more, and low-frequency TENS, which is linked to the body's own endorphin release, as below 10Hz. Session times vary a lot between machines. Some of our manuals suggest sessions of an hour or more, and longer for ongoing pain, so always check yours.

Always follow the programmes, session times and limits in the manual supplied with your machine, and ask a healthcare professional if you are unsure what suits your condition.

Using a TENS machine safely

TENS is a well-established, drug-free option, but it is not suitable for everyone. Always follow the instructions supplied with your machine. Do not use a TENS machine while driving, operating machinery, in the bath or shower, or while asleep.

Do not use a TENS machine if you have a pacemaker or another implanted electrical device, have epilepsy, are being treated for deep vein thrombosis (DVT), or are pregnant, unless your doctor or midwife has told you it is OK.

Speak to your GP, pharmacist or another healthcare professional before using a TENS machine if you:

have a heart condition
have pain that is severe, new, worsening or unexplained

If your skin becomes itchy, red or irritated under the pads, turn the machine off, remove the pads and let it settle. Switching to sensitive skin electrodes can help.

TENS machines in pregnancy and labour

Many people use a TENS machine in the early stages of labour as a drug-free option, and some find it helps them feel more in control through each contraction. The research on how much it reduces labour pain is mixed, so it is best seen as one option alongside others.

Do not use a TENS machine while pregnant unless your doctor or midwife has told you to. Many machines, including our wireless 2 and 4 channel units, should not be used in pregnancy at all, while the Med-Fit 1 manual allows use during labour only. Pads should never be placed on the abdomen. For labour, pads are usually placed on the lower back either side of the spine, and a TENS machine must not be used in a birth pool or bath. Always check with your midwife or GP before using TENS while pregnant, and check your machine's manual confirms it is suitable for use in labour.

TENS electrodes and accessories

Electrode pads are consumable. They lose their stick over time and need replacing when adhesion drops, as a pad that does not stick well will not deliver the pulses properly. Wireless and wired machines use different pads, so check which your machine takes before you reorder.

Browse our full range of TENS electrodes, including sensitive skin and back electrodes, plus wireless TENS accessories, batteries and chargers and cables.

TENS machine FAQs

Do TENS machines actually work?

For many people, yes, as a way to temporarily ease minor aches and pains. Results vary from person to person and TENS does not work for everyone. It tends to work best as part of a wider routine rather than on its own. Our guide to the pros and cons of a TENS machine gives a balanced view.

What does a TENS machine feel like?

Most people describe a tingling, buzzing or gentle pulsing sensation under the pads. You control the strength, so it should always feel comfortable.

Where do I put the TENS pads?

On clean, dry skin on or around the painful area, with a gap between them so they never touch. Keep them off the neck, head, chest and any broken skin.

How long should I use a TENS machine for?

It depends on your machine, so always follow the session times in your manual. Some of our manuals suggest sessions of an hour or more, and longer for ongoing pain.

How often can I use a TENS machine?

It depends on your machine. Our Med-Fit 1 manual, for example, suggests 2 to 4 sessions a day. Take breaks, move the pads slightly each time to look after your skin, and follow your manual.

What setting should I use on my TENS machine?

Start with the preset programmes and the lowest intensity, then turn it up slowly to a clear but comfortable tingle. Most people start with a conventional, higher-frequency TENS programme. Lower frequencies are linked to the body's own endorphin release.

How high should I set my TENS machine?

High enough to feel a clear but comfortable tingle, and no higher. It should never hurt. Your body gets used to the sensation during a session, so you may need to nudge it up a little as you go.

Can a TENS machine make pain worse?

If your pain feels worse during or after a session, the intensity may be too high or the pads may be in the wrong place. Turn it down or move the pads. If your pain keeps getting worse, stop and speak to a healthcare professional.

Is a TENS machine safe?

TENS is a well-established, drug-free treatment, but it is not suitable for everyone. Do not use one if you have a pacemaker, epilepsy or DVT, or are pregnant, unless your doctor or midwife has told you to. Check with a healthcare professional first if you have a heart condition, and always follow your manual.

Can I use a TENS machine if I have a pacemaker?

No. NHS guidance says not to use TENS if you have a pacemaker, and our manuals and product pages say the same. Speak to your GP or cardiologist about other options.

Can a TENS machine affect your heart?

Pads placed around the heart may affect its rhythm, which is why they should never go on your chest, and why you should not use pads on your chest and back at the same time. If you have a heart condition, speak to your GP first. If you have a pacemaker, do not use TENS.

Can I use a TENS machine when pregnant or in labour?

Do not use TENS while pregnant unless your doctor or midwife tells you to. Many people use one in labour with their midwife's agreement, with the pads on the lower back. Never place pads on the abdomen.

Can I use a TENS machine alongside painkillers?

Yes. TENS is drug-free, so many people use it alongside their usual medication. Ask your pharmacist or GP about the right approach for you.

What is the difference between TENS and EMS?

TENS targets the nerves to help manage pain. EMS targets the muscles to make them contract for conditioning and recovery. Many of our machines offer both.

Are wireless TENS machines as good as wired ones?

For everyday pain relief, yes. Both work in the same way. Wireless adds freedom of movement and discretion, which is why many people now choose it.

Can I wear a wireless TENS machine under my clothes?

Yes. With no trailing leads the unit hides easily under clothing, so you can keep moving through your day while you use it.

How do I choose the right TENS machine?

Start with how many areas you want to treat. Single channel covers one area, dual channel covers two and four channel gives the widest coverage. Then decide between wireless for freedom of movement or wired for a lower cost.

Do wireless and wired TENS machines use the same pads?

No, they are not interchangeable. Order the pads that match your machine from our TENS electrodes range.

How often should I replace TENS pads?

Replace them when they stop sticking firmly. How long they last depends on how often you use them, how clean your skin is and how well you store them between sessions.

Need help choosing? Get in touch with the Med-Fit team and we will point you to the right machine.