Magnets: Findings from Scientific Studies and Clinical Trials
Questions & Answers About Using Magnets to Treat Pain - Part 3
7. How are electromagnets used in attempts to treat pain?
Electromagnets were approved by the FDA 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) is also 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
8. 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 either a general review, a systematic review, or a meta-analysis. There are not many reviews available on CAM uses of magnets to treat pain. Appendix II provides examples of six reviews published from August 1999 through August 2003 in English in the National Library of Medicine's MEDLINE database.
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 studies in Appendix III give an overview of scientific research from 15 RCTs published in English from January 1997 through March 2004 and cataloged in the National Library of Medicine's MEDLINE database. These trials studied CAM uses of static magnets or electromagnets for various kinds of pain.
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.
NCCAM has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your primary health care provider. We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy in this information is not an endorsement by NCCAM.
National Center for Complementary and Alternative Medicine (NCCAM)
National Institutes of Health
Bethesda, Maryland 20892 USA
NCCAM Publication No. D208