PEMF (pulsed electromagnetic fields)

What PEMF is and how it is supposed to work

PEMF stands for pulsed electromagnetic fields. The devices send current in short pulses through coils, which creates a magnetic field that changes constantly. Such a field induces weak electrical currents in tissue. This must be distinguished from magnetic stimulation of the brain, which directly excites nerve cells with strong pulses; it is described on a separate page: Neurostimulation (tDCS / TMS). Static magnets, for example in bracelets, are something else again.

The therapy is justified with laboratory findings: there, electromagnetic fields can stimulate the formation of new bone, and in cartilage, piezoelectric effects and streaming potentials are discussed as a mode of action. Whether these mechanisms explain the measured pain relief in the human joint is open. Common explanations for the home mats, such as more ATP in the mitochondria or better microcirculation, have not been shown as a mode of action in humans.

What the studies show

Cochrane 2013 — osteoarthritis

9 randomized studies with 636 participants, comparison with placebo or sham. After 4 to 26 weeks, treated patients rated their pain relief 15.1 points better on a scale from 0 to 100 (95 percent confidence interval 9.1 to 21.1). Physical function according to WOMAC did not improve significantly, nor did quality of life. In four studies with up to 288 participants, side effects did not occur more often than with sham; there were no serious ones.

Chang 2026 — knee osteoarthritis, more recent studies

9 randomized studies from 2015 to 2025 with 457 patients. After one month there was no significant benefit for pain on the visual scale or for the WOMAC total score. Individual subscores improved at certain time points, such as stiffness and daily activity after one month; objective function tests did not. The risk of bias was high overall, and the authors doubt that the improvements are clinically noticeable.

Sun 2022 — back pain

14 randomized studies with 618 participants. Compared with placebo, PEMF clearly relieved pain; as an add-on to other therapies, a smaller benefit also emerged. This was significant in chronic, not in acute back pain. Physical function did not improve significantly.

Mansour 2025 — fatigue in multiple sclerosis

7 randomized, sham-controlled studies with 327 participants. Fatigue decreased somewhat more under PEMF than under sham, with a small standardized mean difference of minus 0.23, narrowly significant. Quality of life and depressive symptoms did not differ.

Cochrane 2011 — bone fractures that do not heal

4 blinded, placebo-controlled studies with 125 participants, three of them with PEMF, mostly on non-healing tibial fractures. The proportion of healed fractures was not significantly higher with treatment (relative risk 1.96, confidence interval 0.86 to 4.48). In two studies there was no pain relief. The authors consider the data insufficient.

Where the data stop

PEMF is not a uniform treatment. The studies differ so much in frequency, field strength, treatment duration and number of sessions that a result cannot be transferred to another device. Many studies are small, and several overviews rate the quality as low to moderate. The pain effect is most likely short-term; a clear functional gain has not been shown.

For the typical promises of the home mats, more cellular energy, better circulation, deeper sleep, faster recovery or longevity, no studies appear in the overviews evaluated here. Data on daily use over years are also lacking. A study result initially applies only to the device and protocol used there.

Status, approval and legal

In Germany, magnetic field therapy without implanted coils is not a prescribable remedy under the G-BA’s Remedies Directive; it is on the list of measures whose therapeutic benefit has not been demonstrated. Statutory health insurers therefore do not pay for it as a remedy.

In the US there is a separate device class for non-thermal, pulsed shortwave therapy: prescription devices that deliver pulsed electromagnetic energy in the radiofrequency range of 13.56 or 27.12 megahertz, for adjunctive relief of pain and swelling after surgery. This concerns a specific technique and indication, not the low-frequency mats for use at home.

Safety

In the studies, PEMF is well tolerated. In the Cochrane analysis on osteoarthritis, side effects did not occur more often than with sham; serious ones were not reported. However, side effects were recorded only in some of the studies and over a few weeks.

For people with a pacemaker, defibrillator or other electronic implants and for pregnant women, the studies provide no safety data. If this applies to you, have the use checked by a physician beforehand. For joint or back pain, a mat does not replace investigating the cause.

Sources

• Li et al., Cochrane Database Syst Rev 2013 (osteoarthritis)
• Chang et al., Medicina (Kaunas) 2026 (knee osteoarthritis, meta-analysis)
• Markovic et al., Wien Klin Wochenschr 2022 (osteoarthritis, overview of reviews)
• Sun et al., Clin Rehabil 2022 (back pain, meta-analysis)
• Mansour et al., Mult Scler Relat Disord 2025 (fatigue in MS, meta-analysis)
• Griffin et al., Cochrane Database Syst Rev 2011 (non-healing bone fractures)
• G-BA, Remedies Directive (Heilmittel-Richtlinie), version of October 29, 2024 (Annex 1: remedies not eligible for prescription)
• US Code of Federal Regulations, 21 CFR 890.5290 (shortwave diathermy)