TENS Therapy for Pain Relief: What It Is, How It Works, and the Evidence

What is TENS?

TENS stands for transcutaneous ("across the skin") electrical nerve stimulation. A small, battery-powered unit connects to adhesive electrode pads that you place on the skin around a painful area. The device sends gentle electrical pulses that you feel as a tingling or buzzing sensation. It is a non-invasive, drug-free option often used as part of a wider physiotherapy plan.

Because the units are small and portable, TENS is one of the modalities a home physiotherapist can bring to a visit and, where appropriate, teach you to use yourself between sessions.

How TENS works

Two mechanisms are commonly proposed. Under the pain-gate theory, stimulating the sensory nerves with a comfortable current helps "close the gate" on pain signals travelling up the spinal cord to the brain, so you feel less pain. TENS is also thought to encourage the release of endorphins, the body’s own pain-relieving chemicals.

In practice, the exact mechanism is not fully established, and clinicians choose settings (intensity, frequency, and pad placement) based on your response. A strong-but-comfortable intensity applied at or near the pain site tends to be the most effective approach in studies.

What conditions is TENS used for?

TENS is used across a range of painful musculoskeletal and other conditions, usually to manage symptoms while active rehabilitation does the longer-term work.

• Osteoarthritis (for example, knee pain)
• Low back and neck pain
• Post-surgical pain
• Nerve-related and other chronic pain
• Labour pain

What the evidence says

The largest synthesis to date — a 2022 systematic review and meta-analysis of 381 randomised trials (the meta-TENS study) — found moderate-certainty evidence that strong, non-painful TENS applied at the site of pain produces a clinically important reduction in pain intensity during or immediately after treatment, with no serious adverse events reported.

The honest limitation is duration: a Cochrane overview of reviews concluded that, for chronic pain specifically, the longer-term evidence is of very low quality, so we cannot claim TENS provides lasting relief. For acute post-operative pain, reviews have found it can reduce pain and lower the need for pain medication. The sensible takeaway is that TENS is a safe, useful tool for short-term, drug-free relief that supports — but does not replace — exercise-based recovery.

Using TENS at home

TENS units are inexpensive, portable, and battery-powered, and the pads can be repositioned, which makes supervised home use practical. A physiotherapist can assess whether TENS is appropriate for you, set safe pad placement and intensity, and show you how to use it for day-to-day symptom management between visits.

Safety and who should be cautious

TENS has an excellent safety profile, with mild skin irritation under the pads being the most common side effect. However, some people should avoid it or seek advice first.

• Do not use if you have a pacemaker or other implanted electrical device.
• Seek medical advice first if you are pregnant, or have epilepsy, heart disease, or a bleeding disorder.
• Never place pads over broken, infected, or numb skin, the front or sides of the neck, the eyes, mouth, or head.
• Do not use on new or unexplained pain before it has been assessed, and avoid use while driving or near water.

Sources

• Johnson MI, et al. Efficacy and safety of TENS for acute and chronic pain (the meta-TENS study), 2022
• Gibson W, et al. TENS for chronic pain — an overview of Cochrane Reviews, 2019
• Healthdirect Australia — TENS (transcutaneous electrical nerve stimulation)

Other modalities

• Therapeutic ultrasound
• Muscle stimulation (NMES / EMS)
• Interferential current therapy (IFC)
• Heat and cold therapy
• Low-level laser / red-light therapy (LLLT)
• Resistance bands
• Weights & resistance training
• Pneumatic resistance training
• Cable functional trainer
• Motorised cycling therapy
• Supported treadmill gait training