In the middle decades of the twentieth century, scientists in various parts of the world began performing studies on the therapeutic use of magnets. From the 1940s on, magnets became increasingly popular in Japan. Yoshio Manaka, one of the influential Japanese acupuncturists of the twentieth century, used magnets in conjunction with acupuncture. Magnet therapy also became a commonly used technique of self-administered medicine in Japan. For example, a type of plaster containing a small magnet became popular for treating aches and pains, especially among the elderly. Magnetic mattress pads, bracelets, and necklaces also became popular—again, mainly among the elderly. During the 1970s, both magnets and electromagnetic machines became popular among athletes in many countries for treating sports-related injuries.
Types of Magnet Therapy and Their Uses
The term magnet therapy usually refers to the use of static magnets placed directly on the body, generally over regions of pain. Static magnets are either attached to the body by tape or encapsulated in specially designed products such as belts, wraps, or mattress pads. Static magnets are also sometimes known as permanent magnets.
Static magnets come in various strengths. The units of measuring magnet strength are gauss and tesla. One tesla equals 10,000 gauss. A refrigerator magnet, for example, is around 200 gauss. Therapeutic magnets measure anywhere from 200 to 10,000 gauss, but the most commonly used measure 400 to 800 gauss.
Pulsed Electromagnetic Field Therapy (PEMF)
Pulsed electromagnetic field therapy (PEMF) is quite distinct from magnet therapy itself. (The term “electromagnetic field” does not, in this case, refer to magnetism in the ordinary sense.) Nonetheless, for historical reasons, it is often classified together with true magnetic therapies. Because of that, we discuss it here.
Bone has a remarkable capacity to heal from injury. In some cases, though, the broken ends do not join, called non-union fractures. PEMF therapy has been used to stimulate bone repair in non-union and other fractures since the 1970s; this is a relatively accepted use and will not be discussed here. More controversially, PEMF has shown promise for osteoarthritis, stress incontinence, and possibly other conditions as well.
Osteoarthritis
Three double-blind, placebo-controlled studies enrolling a total of more than 350 people suggest that pulsed electromagnetic field therapy can improve symptoms of
For example, a double-blind, placebo-controlled study tested PEMF in 86 people with osteoarthritis of the knee and 81 with osteoarthritis of the cervical spine. Participants received 18 half-hour sessions with either a PEMF machine or a sham device. The treated participants showed significantly greater improvements in disease severity than those given placebo. For both osteoarthritis conditions, benefits lasted for at least 1 month after treatment was stopped.
A more recent double-blind trial evaluated low-power, extremely low-frequency pulsed electromagnetic fields for the treatment of knee osteoarthritis. A total of 176 people received eight sessions of either sham or real treatment over a period of 2 weeks. The results showed significantly greater pain reduction in the treated group.
Stress Incontinence
Many women experience stress incontinence, the leakage of urine following any action that puts pressure on the bladder. Laughter, physical exercise, and coughing can all trigger this unpleasant occurrence. A recent study suggests that PEMF treatment might be helpful. In this placebo-controlled study, researchers applied high-intensity pulsating magnetic fields to 62 women with stress incontinence.14 The intention was to stimulate the nerves that control the pelvic muscles.
The results showed that one session of magnetic stimulation significantly reduced episodes of urinary leakage over the following week, compared to placebo. In the treated group, 74% experienced significant improvement, compared to only 32% in the placebo group. Presumably, the high-intensity magnetic field used in this treatment created electrical currents in the pelvic muscles and nerves. This was confirmed by objective examination of 13 patients, which found that magnetic stimulation was in fact increasing the strength of closure at the exit from the bladder. However, there was one serious flaw in this study: it does not appear to have been double-blind. (For more information on why this is important, see Why Does This Database Rely on Double-blind Studies?) Researchers apparently knew which participants were getting real treatment and which were not, and therefore might have unconsciously biased their observations to conform to their expectations. Thus, the promise of electromagnetic therapy for stress incontinence still needs to be validated in properly designed trials.
Multiple Sclerosis
A 2-month, double-blind, placebo-controlled study of 30 people with multiple sclerosis was conducted using a PEMF device.13 Participants were instructed to tape the device to one of three different acupuncture points on the shoulder, back, or hip. The study found statistically significant improvements in the treatment group, most notably in bladder control, hand function, and muscle spasticity. Benefits were seen in another small study too.58
Erectile Dysfunction
In a 3-week, double-blind, placebo-controlled trial, 20 men with erectile dysfunction received PEMF therapy or placebo.30 The magnetic therapy was administered by means of a small box worn near the genital area and kept in place as continuously as possible over the study period; neither participants nor observers knew whether the device was actually activated or not. The results showed that use of PEMF significantly improved sexual function compared to placebo.
Migraines
In a double-blind trial, 42 people with migraine headaches were given treatment with real or placebo pulsed electromagnetic therapy to the inner thighs for 1 hour, 5 times per week for 2 weeks. The results showed benefits in headache frequency and severity. However, the study design was rather convoluted and nonstandard, and, therefore, the results are difficult to interpret.
Electromagnetic Therapy: Repetitive Transcranial Magnetic Stimulation
Unlike PEMF, repetitive transcranial magnetic stimulation (rTMS) does in fact involve magnetic fields, and is, therefore, more closely related to standard magnet therapy. It involves applying low-frequency magnetic pulses to the brain. rTMS has been investigated for treating emotional illnesses and other conditions that originate in the brain. The results of preliminary studies have been generally promising.
Depression
About 20 small studies have evaluated rTMS for the treatment of depression (including severe depression that does not respond to standard treatment, as well as the depressive phase of bipolar illness), and most found it effective.
In one of the best of these studies, 70 people with major depression were given rTMS or sham rTMS in a double-blind setting over a period of 2 weeks The results showed that participants who had received actual treatment experienced significantly greater improvement than did those receiving sham treatment.
In another trial involving 92 older patients whose depression had been linked to poor blood flow to the brain (so-called vascular depression), actual rTMS was significantly more effective than sham rTMS. Benefits were more notable in younger patients.
Two separate studies suggest that rTMS may be an effective additional treatment for the 20%-30% of depressed people for whom conventional drug therapy is not successful. ECT (electroconvulsive therapy, or shock treatment) is often used for people who fall in this category, but rTMS may be an equally effective and less traumatic alternative.
Epilepsy
In a double-blind, placebo-controlled trial, 24 people with epilepsy (technically, partial complex seizures or secondarily generalized seizures) not fully responsive to drug treatment were given treatment with rTMS or sham rTMS twice daily for a week.The results showed a mild reduction in seizures among the people given real rTMS. However, the benefits rapidly disappeared when treatment was stopped. Similarly short-lived effects were seen in an open trial.
Schizophrenia
A double-blind, placebo-controlled crossover trial looked at the use of low-frequency rTMS in 12 people diagnosed with schizophrenia and manifesting frequent and treatment-resistant auditory hallucinations (hearing voices). Participants received rTMS for 4 days, with length of treatment building from 4 minutes on the first day to 16 minutes on the fourth day. Active stimulation significantly reduced the incidence of auditory hallucinations compared to sham stimulation. The extent of the benefit varied widely, lasting from 1 day in one participant to 2 months in another. Possible benefits were seen in other small studies as well.
Parkinson's Disease
A 2-month, double-blind, placebo-controlled trial of 18 people with Parkinson’s disease compared rTMS against placebo. The results suggest that rTMS therapy can improve Parkinson’s symptoms. Benefits were seen in two other small studies too.
Myofascial Pain Syndrome
Myofascial pain syndrome is a condition similar to fibromyalgia but more localized; while fibromyalgia involves tender trigger points all over the body, myofascial pain syndrome involves trigger points clustered in one portion of the body only. One controlled trial found indications that a form of rTMS applied to the painful area (rather than to the brain) may be effective for myofascial pain syndrome of the trapezius muscle.
Surgery Support (Reducing Pain)
One study of 165 people failed to find that use of static magnets over the surgical incision reduced post surgical pain.
Tinnitus
One preliminary study found indications that rTMS may be helpful for (ringing in the ear).
Post-traumatic Stress Disorder
A small, double-blind, placebo-controlled study found that use of rTMS may be able to reduce symptoms of post-traumatic stress disorder.
Cigarette Addiction
A very small, double-blind, placebo-controlled study found evidence that rTMS may reduce craving for cigarettes in people attempting to give up smokeing Myotropic Lateral Sclerosis (Lou Gerhig’s Disease)
Amyotrophic lateral sclerosis (ALS) is a nerve disorder that causes progressive muscle weakness. A small pilot study hinted that rTMS may be beneficial at least temporarily.
