Magnet Therapy

Mesmer and animal magnetism

Franz Anton Mesmer (1734-1815) was an Austrian physician who held that an invisible fluid ran within people and between a subject and a practitioner, whom he called the magnetizer. A historical review published in 2009 in a Croatian medical-history journal, with an English abstract, describes this idea under the names mesmerism, animal magnetism and fluidum, and treats Mesmer as an early figure in the history of hypnosis and psychotherapy. The theory concerned a bodily fluid and the practitioner's influence on it.

The sources reviewed do not describe animal magnetism as the use of permanent magnets in products of the kind sold today. The same review notes that the term hypnosis was introduced in the 1840s by the Scottish surgeon James Braid, which separates later hypnotic practice from Mesmer's own theory.

The 1780 trial proposal and the 1784 commissions

A 2005 article in the Journal of the Royal Society of Medicine reports that in September 1780 Mesmer, through an associate, proposed to the Paris medical faculty a trial of 24 patients in two groups of 12, with patients assigned by drawing lots to conventional treatment or to animal magnetism. The faculty rejected the proposal. The author describes it as possibly the second earliest proposal of random allocation in a clinical trial, a characterization that rests on that article alone.

In 1784 two French commissions examined animal magnetism. A 2002 historical article by Spiegel interprets the panel's report as negative about the literal theory of animal magnetism but as supportive of the potential power of suggestion. A 2005 article by Burkhard Peter argues that the exorcist Johann Joseph Gassner, who was at the center of a heated Munich dispute around 1775 in which Mesmer took part, was a more direct predecessor of hypnosis than Mesmer.

What the sources do not establish

The sources reviewed for this article do not trace a continuous line from eighteenth-century animal magnetism to present-day magnetic bracelets, insoles and mattress pads, and they give no dated account of earlier medical uses of lodestones or permanent magnets. The National Center for Complementary and Integrative Health (NCCIH), a United States government research agency, lists wraps, jewelry, mats and bed pads among current static magnet products. Modern magnet products should therefore not be presented as an unchanged tradition.

Static magnets and magnetic field therapy

Magnet therapy is an umbrella label. NCCIH distinguishes static or permanent magnets, whose field is constant and which are sold as wraps, jewelry, mats and bed pads, from electromagnets, whose field strength varies with an electric current. Research articles on the first group often use the phrase static magnetic field (SMF) therapy, and PubMed indexes the topic under the heading Magnetic Field Therapy.

Pulsed electromagnetic fields and related terms

Pulsed electromagnetic field (PEMF) therapy is a separate intervention, delivered by a device that produces a time-varying field, and NCCIH reports the evidence for it separately from the evidence for static magnets. Cochrane reviews of electrotherapy list PEMF and repetitive magnetic stimulation as different modalities from permanent magnets. Findings for one of these should not be carried over to another, and this page covers static magnets, with PEMF mentioned for context only.

Magnet strength and units

Trials of wearable magnets usually report field strength in gauss. One rheumatoid arthritis trial described a standard wrist strap as 1502 to 2365 gauss, an attenuated strap as 250 to 350 gauss and a demagnetized strap as under 20 gauss. A review of dosing for static fields argues that the site of the target tissue, the distance of the magnet from it and the schedule all need reporting, and found that the field reaching the tissue could not be characterized in most of 56 earlier clinical studies.

Products and how they are used

NCCIH describes static magnets as sold in wraps, jewelry such as bracelets, shoe insoles, mats, mattress pads and bandages, and as marketed for pain including foot and back pain and arthritis. Use is typically self-directed, with the device worn or placed against the body for hours or weeks, and no practitioner session is required. The sources reviewed do not describe a standard protocol, training standard or professional register for magnet therapy.

Devices and schedules used in trials

In the osteoarthritis trial, 45 patients each wore four devices over 16 weeks: a commercial magnetic wrist strap, a weak magnetic strap, a demagnetized strap and a copper bracelet. In the rheumatoid arthritis trial, 70 patients wore four devices in different orders, each for five weeks with one-week washouts between them. These are research protocols and not recommended regimens.

Pain and arthritis

Magnets are marketed mainly for pain, including pain from arthritis and fibromyalgia, according to NCCIH. The investigators of the rheumatoid arthritis trial describe magnets and copper applied to the skin as folklore remedies for pain and inflammation in that condition and note that little research had evaluated them before their study.

Marketing claims and their stated basis

The authors of the 2007 meta-analysis note that static magnets are marketed with claims of effectiveness for reducing pain, although evidence of scientific principles or biological mechanisms to support such claims is limited. Practitioner or commercial explanations of how magnets act on the body were not verified in the sources reviewed, and no mechanism is presented here as established.

Other conditions studied

Static magnetic fields have also been tested for neck pain in a necklace trial, for pain and muscle strength in postpolio syndrome, and as an add-on for exercise-induced pain in painful diabetic neuropathy. These are research questions, not endorsed uses, and each is covered by a different review below.

Pooled analysis of pain trials

A 2007 systematic review and meta-analysis by Pittler, Brown and Ernst in the Canadian Medical Association Journal searched to March 2007 and identified 29 potentially relevant randomized trials. Nine placebo-controlled trials measuring pain on a 100-mm visual analogue scale were pooled, giving a weighted mean difference of 2.1 mm in favor of magnets (95% confidence interval -1.8 to 5.9 mm), which is not statistically significant. The authors concluded that the evidence does not support static magnets for pain relief, and that for osteoarthritis it was insufficient to exclude a clinically important benefit.

Wrist straps and bracelets in arthritis

In the 2009 osteoarthritis trial, no difference between devices was seen for pain, stiffness, physical function or medication use. A secondary analysis of one pain subscale favored the standard magnet, with no adjustment for multiple testing. In the 2013 rheumatoid arthritis trial, 65 of 70 participants gave complete data and no significant differences appeared between the four devices for pain, inflammation, function or disease activity. Both trials were small and were conducted in general practice patients in Yorkshire.

Other reviews that include static magnets

A Cochrane review of electrotherapy for neck pain, with searches to August 2012, rated the evidence as low quality that a permanent magnet necklace was no more effective than placebo (one trial, 52 participants; standardized mean difference 0.27, 95% confidence interval -0.27 to 0.82). A 2007 meta-analysis of physical agents for knee osteoarthritis found static magnets gave no statistically significant short-term pain relief over placebo. A Cochrane review of postpolio syndrome found two single trials suggesting static magnetic fields might help muscle strength and pain, rated moderate quality, and called for further investigation.

A 2020 systematic review of non-drug treatments for painful peripheral neuropathy reported that adjuvant static magnetic field therapy could lead to a significant decrease in exercise-induced pain in painful diabetic neuropathy, at level II evidence. This finding is specific to that population and outcome. No Cochrane review devoted solely to static magnets for pain was found in the searches run for this draft.

Dosimetry and trial design

Proponents of static field therapy have argued that negative trials may reflect inadequate or inappropriate dosing, and a 2008 communication proposed ten dosing parameters and phase I dose-finding studies before large trials. The Pittler review found significant heterogeneity among trials that used other pain scales, so pooling them was unreliable. The reviews above did not establish what dose, if any, would give a benefit.

Limits of the evidence base

Trials were mostly small, short and limited to musculoskeletal pain, and the Cochrane authors judged the evidence for neck pain and postpolio syndrome to be low or moderate quality. A weak or demagnetized magnet can be a plausible placebo, but participants might detect field strength in a stronger device. The sources reviewed for this article do not report blinding checks, so this possibility is left open.

Implanted cardiac devices

A clinical study in Zurich tested four small neodymium-iron-boron magnets (two spheres, a necklace of 45 spherical magnets and a magnetic name tag) in 41 patients with pacemakers and 29 with implantable cardioverter-defibrillators. Magnetic interference was observed in all patients, at a maximum distance of 3 cm, with no significant differences by manufacturer or device type. The authors advised cautioning patients about such magnets in daily life. NCCIH likewise states that magnets may interfere with pacemakers and insulin pumps.

Imaging, pregnancy and children

NCCIH advises removing magnetic devices before magnetic resonance imaging, consulting a health care provider before use during pregnancy or with health conditions, and keeping magnets out of reach of children because ingestion can be fatal. These statements come from a single government summary and were not independently checked against device standards in this draft.

Reported effects and care boundaries

NCCIH describes static magnets as generally considered safe when applied to the skin, apart from these cautions. The osteoarthritis trial authors reported no major adverse effects, and a review of complementary therapies in rheumatoid arthritis found no reports of major adverse events. Trials were small, and absence of reports does not exclude rare harms. NCCIH advises against using magnets to replace conventional care or to delay evaluation of pain or other medical problems.