TENS Machines for Pain Relief: Do They Actually Work?

TENS stands for Transcutaneous Electrical Nerve Stimulation. It's a small, battery-powered device connected by wires to sticky pad electrodes, which you place on your skin near or around the painful area. Once switched on, it delivers a mild electrical current that produces a tingling sensation.

The theory behind it is called the gate control theory of pain, first described by Melzack and Wall in the 1960s. In simple terms, the idea is that the electrical stimulation activates large nerve fibres that carry non-painful signals, and these can partially "close the gate" in the spinal cord to the smaller fibres that carry pain signals up to the brain. Some machines also aim to trigger the release of the body's own natural pain-relieving chemicals. The result, for some people, is a genuine reduction in how painful the area feels while the machine is switched on, or for a short time afterwards.

This is the part worth being honest about: the evidence for TENS is genuinely mixed. A 2019 overview of Cochrane reviews looking at TENS for chronic pain found that, while the reviews themselves were well conducted, the underlying evidence was of very low quality — the authors couldn't conclude with confidence that TENS meaningfully helps pain, disability or quality of life, but they also couldn't conclude that it's harmful (Gibson et al., Cochrane overview, 2019).

NICE's guideline on low back pain and sciatica goes further and specifically recommends against offering electrotherapies, including TENS, for low back pain (NICE guideline NG59). That doesn't mean nobody gets relief from it — plenty of people do, and it's cheap, low-risk and easy to try — but it does mean TENS shouldn't be marketed or relied on as a proven treatment for the underlying problem. It's best thought of as one option among several for taking the edge off pain, not a treatment with strong evidence behind it.

Electrode placement matters. As a general starting point, pads go on clean, dry, unbroken skin either side of the painful area, with a gap between them, rather than directly on top of the most tender spot. Avoid placing pads over the front or sides of the neck, across the chest, over the eyes, over broken or irritated skin, or over varicose veins. If your skin becomes itchy, irritated or red, turn the machine off and remove the pads (NHS guidance on TENS).

There are also some genuine contraindications. You should seek medical advice before using a TENS machine if you have a pacemaker or any other implanted electrical device, if you are pregnant (particularly for pad placement over the abdomen or lower back without specific guidance), or if you have epilepsy. If any of these apply to you, check with your GP or physiotherapist first rather than assuming it's fine.

The way I'd frame it for patients: TENS can be a useful adjunct for taking the edge off symptoms — for example, to make a flare-up more manageable while you keep moving, or to settle pain enough that you can get through a set of home exercises comfortably. It doesn't address why the pain is there in the first place, so it isn't a substitute for identifying and treating the underlying cause, whether that's through a structured strength and rehab programme or, for something like stubborn heel pain, a treatment such as shockwave therapy. Think of it as symptom control that buys you comfort to do the things that actually drive recovery, not a replacement for them.

Can I use a TENS machine every day?
Most people can use TENS daily as needed, with breaks between sessions and checks on your skin for irritation. If you're using it very frequently for persistent pain, it's worth getting that pain properly assessed rather than just managing around it.

Do I need a prescription to buy one?
No — TENS machines are widely available over the counter and online in the UK. That accessibility is part of why it's worth understanding the evidence and safety points above before you buy one.

Will a TENS machine fix my problem on its own?
Unlikely. It may help you feel more comfortable, but it doesn't address the underlying cause of most musculoskeletal pain. Pairing it with an accurate assessment and a proper rehab plan gives you a much better chance of lasting improvement.