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Magnets are objects that produce a type of energy called magnetic fields. Magnets are widely marketed to treat or ease the symptoms of various diseases and conditions, including pain. This article provides an overview of the use of magnets for pain, summarizes current scientific knowledge about their effectiveness for this purpose, and suggests additional sources of information.
What Are Magnets?
Magnets are objects that produce a type of energy called magnetic fields. All magnets possess a property called polarity — that is, a magnet's power of attraction is strongest at its opposite ends, usually called the north and south poles. The north and south poles attract each other, but north repels north and south repels south. All magnets attract iron.
Magnets come in different strengths, most often measured in units called gauss (G). For comparison purposes, the Earth has a magnetic field of about 0.5 G; refrigerator magnets range from 35 to 200 G; magnets marketed for the treatment of pain are usually 300 to 5,000 G; and MRI (magnetic resonance imaging) machines widely used to diagnose medical conditions noninvasively produce up to 200,000 G.1
The vast majority of magnets marketed to consumers for health purposes are of a type called static (or permanent) magnets. They have magnetic fields that do not change.
Examples of Products Using Magnets
· Heel inserts
· Mattress pads
· Bandages
· Belts
· Pillows and cushions
· Bracelets and other jewelry
· Headwear
The other magnets used for health purposes are called electromagnets, because they generate magnetic fields only when electrical current flows through them. The magnetic field is created by passing an electric current through a wire coil wrapped around a magnetic core. Electromagnets can be pulsed —that is, the magnetic field is turned on and off very rapidly.
Is the Use of Magnets Considered Conventional Medicine or Complementary and Alternative Medicine?
Conventional medicine and complementary and alternative medicine (CAM) are defined below.
About CAM and Conventional Medicine
Complementary and alternative medicine (CAM) is a group of various medical and health care systems, practices and products that are not presently considered to be part of conventional medicine. Conventional medicine is medicine as practiced by holders of M.D. (medical doctor) or D.O. (doctor of osteopathy) degrees and by allied health professionals, such as physical therapists, psychologists and registered nurses.
There are some uses of electromagnets within conventional medicine. For example, scientists have found that electromagnets can be used to speed the healing of bone fractures that are not healing well.2,3 Even more commonly, electromagnets are used to map areas of the brain. However, most uses of magnets by consumers in attempts to treat pain are considered CAM, because they have not been scientifically proven and are not part of the practice of conventional medicine.
What Is the History of the Discovery and Use of Magnets to Treat Pain?
Magnets have been used for many centuries in attempts to treat pain. By various accounts, this use began when people first noticed the presence of naturally magnetized stones, also called lodestones. Other accounts trace the beginning to a shepherd noticing that the nails in his sandals were pulled out by some stones. By the third century A.D., Greek physicians were using rings made of magnetized metal to treat arthritis and pills made of magnetized amber to stop bleeding. In the Middle Ages, doctors used magnets to treat gout, arthritis, poisoning and baldness; to probe and clean wounds; and to retrieve arrowheads and other iron-containing objects from the body.
In the United States, magnetic devices (such as hairbrushes and insoles), magnetic salves and clothes with magnets applied came into wide use after the Civil War, especially in some rural areas where few doctors were available. Healers claimed that magnetic fields existed in the blood, organs or elsewhere in the body and that people became ill when their magnetic fields were depleted. Thus, healers marketed magnets as a means of "restoring" these magnetic fields. Magnets were promoted as cures for paralysis, asthma, seizures, blindness, cancer and other conditions. The use of magnets to treat medical problems remained popular well into the 20th century. More recently, magnets have been marketed for a wide range of diseases and conditions, including pain, respiratory problems, high blood pressure, circulatory problems, arthritis, rheumatism and stress.
How Common Is the Use of Magnets to Treat Pain?
A 1999 survey of patients who had rheumatoid arthritis, osteoarthritis or fibromyalgia and were seen by rheumatologists reported that 18 percent had used magnets or copper bracelets, and that this was the second-most-used CAM therapy by these patients, after chiropractic.6 One estimate places Americans' spending on magnets to treat pain at $500 million per year; the worldwide estimate is $5 billion.7 Many people purchase magnets in stores or over the Internet to use on their own without consulting a health care provider.
What Are Some Examples of Theories and Beliefs About Magnets and Pain?
Some examples of theories and beliefs about using magnets to treat pain are listed below. These range from theories proposed by scientific researchers to claims made by magnet manufacturers. It is important to note that while the results for some of the findings from the scientific studies have been intriguing, none of the theories or claims below has been conclusively proven:
· Static magnets might change how cells function.
· Magnets might alter or restore the equilibrium (balance) between cell death and growth.
· Because it contains iron, blood might act as a conductor of magnetic energy. Static magnets might increase the flow of blood and, therefore, increase the delivery of oxygen and nutrients to tissues.
· Weak pulsed electromagnets might affect how nerve cells respond to pain.
· Pulsed electromagnets might change the brain's perception of pain.
· Electromagnets might affect the production of white blood cells involved in fighting infection and inflammation.
Here are two other theories and beliefs:
· Magnets might increase the temperature of the area of the body being treated.
· "Magnetizing" or "re-magnetizing" drinking water or other beverages might allow them to hydrate the body better and flush out more "toxins" than ordinary drinking water.
How Are Static Magnets Used in Attempts to Treat Pain?
Static magnets are usually made from iron, steel, rare-earth elements or alloys. Typically, the magnets are placed directly on the skin or placed inside clothing or other materials that come into close contact with the body. Static magnets can be unipolar (one pole of the magnet faces or touches the skin) or bipolar (both poles face or touch the skin, sometimes in repeating patterns).8 Some magnet manufacturers make claims about the poles of magnets —or example, that a unipolar design is better than a bipolar design, or that the north pole gives a different effect from the south pole. These claims have not been scientifically proven.1,9
A small number of rigorous scientific studies have examined the efficacy of static magnets in treating pain. This evidence is discussed in Question 8 and Appendices II and III.
How Are Electromagnets Used in Attempts to Treat Pain?
Electromagnets were approved by the U.S. Food and Drug Administration in 1979 to treat bone fractures that have not healed well.2,3 Researchers have been studying electromagnets for painful conditions, such as knee pain from osteoarthritis, chronic pelvic pain, problems in bones and muscles, and migraine headaches.3,9-12 However, these uses of electromagnets are still considered experimental by the FDA and have not been approved. Currently, electromagnets to treat pain are being used mainly under the supervision of a health care provider and/or in clinical trials.
An electromagnetic therapy called TMS (transcranial magnetic stimulation) also is being studied by researchers. In TMS, an insulated coil is placed against the head, near the area of the brain to be examined or treated, and an electrical current generates a magnetic field into the brain. Currently, TMS is most often used as a diagnostic tool, but research is also under way to see whether it is effective in relieving pain.13,14 A type of TMS called rTMS (repetitive TMS) is believed by some to produce longer lasting effects and is being explored for its usefulness in treating chronic pain, facial pain, headache and fibromyalgia pain.15,16 A related form of electromagnetic therapy is rMS (repetitive magnetic stimulation). It is similar to rTMS except that the magnetic coil is placed on or near a painful area of the body other than the head. This therapy is being studied as a treatment for musculoskeletal pain.17,18
What Is Known From the Scientific Evidence About the Effectiveness of Magnets in Treating Pain?
Overall, the research findings so far do not firmly support claims that magnets are effective for treatment of pain.
Findings From Reviews of Scientific Studies
Reviews take a broad look at the findings from a group of individual research studies. Such reviews are usually a general review, a systematic review or a meta-analysis. There are not many reviews available on CAM uses of magnets to treat pain.
Often, these reviews compared what is known from the clinical trials of magnets for painful conditions to what is known from conventional treatments or from other CAM treatments for the same condition(s).
One review found that static magnetic therapy may work for certain conditions but that there is not adequate scientific support to justify its use.1
Three reviews found that electromagnetic therapy showed promise for the treatment of some, but not all, painful conditions, and that more research is needed.9,19,20 One of these reviews also looked at two randomized clinical trials (RCTs) of static magnets.9 One reported significant pain relief in subjects using magnets, but the other did not.
Another review concluded that TMS has an effect on the central nervous system that might relieve chronic pain and, therefore, should be studied further.14
The remaining review found no studies on magnets for neck pain and stated that rigorous studies are much needed.21
It is important to note that the reviews pointed out problems with the rigor of most research on magnets for pain.9,14,19,20 For example, many of the clinical trials involved a very small number of participants, were conducted for very short durations (e.g., one study applied a magnet a total of one time for 45 minutes), and/or lacked a placebo or sham group for comparison to the magnet group.19,20 Thus, the results of many trials may not be truly meaningful. Most reviews stated that more and better quality research is needed before magnets' effectiveness can be adequately judged.
Findings From Clinical Trials
The results of trials of static magnets have been conflicting. Four of the nine static magnet trials analyzed found no significant difference in pain relief from using a magnet compared with sham treatment or usual medical care.7,8,22,23 Four trials did find a significant difference, with greater benefit seen from magnets.24-27 The remaining trial compared only a weaker strength magnet to a stronger magnet, and found benefit from both (there was no difference between groups in how much benefit).28
Trials of electromagnets yielded more consistent results. Five out of six trials found that these magnets significantly reduced pain.10,11,17,18,29 The sixth found a significant benefit to physical function from using electromagnets, but not to pain or stiffness.30
Some study authors suggested that a placebo effect could have been responsible for the pain relief that occurred from magnets.22,30
While criticizing many of these studies, it is fair to say that testing magnets in clinical trials has presented challenges. For example, it can be difficult to design a sham magnet that appears exactly like an active magnet. Also, there has been concern about how many participants have tried to determine whether they have been assigned an active magnet (for example, by seeing whether a paperclip would be attracted to it); this knowledge could affect how meaningful a trial's results are.
Are There Scientific Controversies Associated With Using Magnets for Pain?
Yes, there are many controversies. Examples include:
· The mechanism(s) by which magnets might relieve pain have not been conclusively identified or proven.
· Pain relief while using a magnet may be due to reasons other than the magnet. For example, there could be a placebo effect or the relief could come from whatever holds the magnet in place, such as a warm bandage or a cushioned insole.22,24
· Opinions differ among manufacturers, health care providers who use magnetic therapy, and others about which types of magnets (strength, polarity, length of use and other factors) should be used and how they should be used in studies to give the most definitive answers.
· Actual magnet strengths can vary (sometimes widely) from the strengths claimed by manufacturers. This can affect scientists' ability to reproduce the findings of other scientists and consumers' ability to know what strength magnet they are actually using.26,31,32
Have Any Side Effects or Complications Occurred From Using Magnets for Pain?
The kinds of magnets marketed to consumers are generally considered to be safe when applied to the skin.7 Reports of side effects or complications have been rare. One study reported that a small percentage of participants had bruising or redness on their skin where a magnet was worn.33
Manufacturers often recommend that static magnets not be used by the following people1:
· Pregnant women, because the possible effects of magnets on the fetus are not known.
· People who use a medical device such as a pacemaker, defibrillator or insulin pump, because magnets may affect the magnetically controlled features of such devices.
· People who use a patch that delivers medication through the skin, in case magnets cause dilation of blood vessels, which could affect the delivery of the medicine. This caution also applies to people with an acute sprain, inflammation, infection or wound.
There have been rare cases of problems reported from the use of electromagnets. Because at present these are being used mainly under the supervision of a health care provider and/or in clinical trials, readers are advised to consult their provider about any questions.
What Should Consumers Know If They Are Considering Using Magnets to Treat Pain?
It is important that people inform all their health care providers about any therapy they are using or considering, including magnetic therapy. This is to help ensure a safe and coordinated plan of care.
In the studies that did find benefits from magnetic therapy, many have shown those benefits very quickly. This suggests that if a magnet does work, it should not take very long for the user to start noticing the effect. Therefore, people may wish to purchase magnets with a 30-day return policy and return the product if they do not get satisfactory results within one to two weeks.
If people decide to use magnets and they experience side effects that concern them, they should stop using the magnets and contact their health care providers.
If You Buy a Magnet …
· Check on the company's reputation with consumer protection agencies.
· Watch for high return fees. If you see them before purchase, ask that they be dropped and obtain written confirmation that they will be.
· Pay by credit card if possible. This offers you more protection if there is a problem.
· If you buy from sources (such as Web sites) that are not based in the United States, U.S. law can do little to protect you if you have a problem related to the purchase.
Sources: The FDA and the Pennsylvania Medical Society
Research Funding on Use of Magnets for Pain and Other Diseases and Conditions
The National Center for Complementary and Alternative Medicine, a part of the National Institutes of Health, is funding research on the use of magnets for pain and other diseases and conditions. For example, recent projects supported by NCCAM include:
· Static magnets, for fibromyalgia pain and quality of life
· Pulsed electromagnets, for migraine headache pain
· Static magnets, for their effects on networks of blood vessels involved in healing
· TMS, for Parkinson's disease
· Electromagnets, for their effects on injured nerve and muscle cells
In addition, the papers by Alfano et al.,26 Swenson,21 and Wolsko et al.27 report on research funded by NCCAM.