Interferential Current Therapy (IFC): What It Is and the Evidence for Pain Relief

What is interferential current therapy?

Interferential current therapy (IFC, sometimes IFT) is a form of electrical stimulation used mainly for pain relief. The physiotherapist places electrodes around the painful area — often four pads — and passes two medium-frequency electrical currents through the skin so that they cross, or "interfere", inside the body’s tissues.

It belongs to the same family as TENS but is designed to reach more comfortably into deeper tissue.

How it works

Two medium-frequency currents (each around 4,000 Hz, but at slightly different frequencies) are applied through crossing circuits. Where they intersect, they combine to produce a lower-frequency "beat" current deeper in the tissue.

The advantage of using medium-frequency currents is comfort and depth: skin resists medium-frequency current far less than low-frequency current, so it penetrates more comfortably, while the resulting low-frequency beat is what helps modulate pain.

What it is used for

IFC is used mainly for pain, including:

• Low back pain
• Knee and other osteoarthritis pain
• General musculoskeletal pain

What the evidence shows

IFC has encouraging evidence for pain relief. A 2022 meta-analysis of randomised trials found it produced statistically significant reductions in knee osteoarthritis pain, both short-term and longer-term, along with better function scores. For chronic low back pain, a 2023 systematic review found moderate-quality evidence — good for this field — that IFC reduces pain and disability compared with placebo immediately after treatment.

IFC also compares well with TENS: a meta-analysis found it relieves acute and chronic pain at least as effectively, and an experimental study found people rated it markedly more comfortable. In a 2025 double-blind, sham-controlled trial of 200 cardiac-surgery patients, IFC significantly reduced post-operative pain and cut the need for painkillers.

The honest picture is that these benefits are mainly for short-term pain relief, and IFC is not a stand-alone cure — it does not replace exercise. Used as targeted pain relief that supports active rehabilitation, it is a genuinely useful, well-tolerated option.

Using it at home

Small portable IFC units exist, often as combined TENS/IFC devices. Most of the trial evidence, however, comes from clinic-delivered treatment, so home use is best set up and supervised by a physiotherapist who can confirm it is appropriate and safe for you.

Safety and contraindications

IFC shares the cautions common to electrical stimulation modalities.

• Avoid with a pacemaker or other implanted electronic device.
• Avoid over the pregnant abdomen, pelvis, or lower back.
• Avoid near known or suspected tumours.
• Do not use over broken or infected skin or areas of numbness.
• Avoid over areas of active bleeding or a blood clot.

Sources

• Chen HL, et al. Interferential current therapy for knee osteoarthritis: review & meta-analysis. Scientific Reports, 2022
• Rampazo ÉP, et al. Interferential current for chronic low back pain: review & meta-analysis. Braz J Phys Ther, 2023
• de Almeida CC, et al. TENS and interferential current show similar pain relief: review & meta-analysis, 2018

Other modalities

• TENS (transcutaneous electrical nerve stimulation)
• Therapeutic ultrasound
• Muscle stimulation (NMES / EMS)
• 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