a multimillion-pound industry that claims they can cure a laundry list of ailments, especially pain. But do these products work?
What the science says
Despite their popularity, there's little scientific evidence that magnets are beneficial to health. Although they're often used to manage pain in chronic musculoskeletal disorders, one study found that magnetic wrist straps were no better than a placebo.
A total of 45 osteoarthritis (OA) sufferers were randomly allocated to one of four treatments, all using the same devices-a standard magnetic wrist strap; a weakened magnetic wrist strap; a de-magnetized (dummy) wrist strap; and a copper (non-magnetic) bracelet-but in different sequences. Each device was worn for at least eight hours a day for four weeks, after which the patients filled in questionnaires to assess symptoms.
The results showed no significant differences among the devices for pain relief, with similar findings for stiff-ness, physical function and medica-tion use. The overall conclusion was that "magnetic and copper bracelets are generally ineffective for managing pain, stiffness and physical function in osteoarthritis", and that any reported therapeutic benefits were most likely due to "non-specific placebo effects" (Complement Ther Med, 2009; doi: 10.1016/j.ctim.2009. 07.002).
Other studies have arrived at much the same conclusions. In a placebo-controlled trial of 165 patients with postoperative pain, the effects of magnet therapy on pain intensity and opioid requirements were similar to what was seen in patients receiving fake magnet therapy. In fact, the active-magnet group used 1.5 mg more morphine than the fake-magnet group (Anesth Analg, 2007; 104: 290-4).
Similarly, magnets were no more effective than a placebo for carpal-tunnel syndrome and chronic lower-back pain (J Fam Pract, 2002; 51: 38-40; JAMA, 2000; 283: 1322-5), and a meta-analysis of nine randomized, placebo-controlled trials of various pain-related conditions reported that the "evidence does not support the use of static magnets for pain relief" (CMAJ, 2007; 177: 736-42).
However, the pain of OA of the hip and knee was decreased by wearing magnetic bracelets compared with a dummy bracelet in a study of 194 men and women (BMJ, 2004; 329: 1450-4). Also, in a preliminary study of 29 patients with OA of the knee, magnets showed "statistically significant efficacy" compared with a placebo (Altern Ther Health Med, 2004; 10: 36-43). Others found magnets to be better than a placebo for chronic pelvic pain and diabetic neuropathy (Am J Obstet Gynecol, 2002; 187: 1581-7; Arch Phys Med Rehabil, 2003; 84: 736-46).
Nevertheless, some scientists question these findings, pointing out that many so-called 'controlled' tests are unreliable, as participants can usually work out whether they're in the real or fake magnet group, which can affect the results. Indeed, in the BMJ study mentioned above, the patients knew they had real magnets as they often were stuck to their keys in their pockets (BMJ, 2006; 332: 4).
In fact, the authors of that study were themselves aware of the problem (BMJ, 2004; 329: 1450-4). Similarly, the authors of the study on magnet therapy for chronic pelvic pain admitted that "blinding efficacy" was "compromised" (Am J Obstet Gynecol, 2002; 187: 1581-7).
However, it's possible that the conflicting results were due to the strength of the magnets used, as studies that failed to show any effect on pain generally used weaker magnets (19-50 mTesla), while those that found an effect used stronger ones (47-180 mTesla) (BMJ, 2004; 329: 1450-4). Nevertheless, it's clear that more research is needed to determine whether this is indeed the answer.
The bottom line
Although many people swear by magnets, the bulk of the research so far suggests that they're no better than a placebo for relieving pain. Yet, looked at another way, magnets then do have an effect, albeit 'all in the head'. Ultimately, the studies show that the mind is a powerful healer, and if magnets can help it to perform that function, then perhaps they're useful after all.
Static vs pulsed magnetic fields
Magnets are claimed to cure a variety of ills besides pain, although scientific proof is lacking; for example, although magnets supposedly increase circulation, a well-designed study found this wasn't so (Sci Rev Alt Med, 2002; 6: 9-12). Other research shows that magnets are ineffective for snoring, sleep apnoea, tinnitus, and reducing heart rate and blood pressure (Wis Med J, 1997; 96: 35-7; Clin Otolaryngol Allied Sci, 1991; 16: 371-2; Clin Rehabil, 2002; 16: 669-74).
However, static magnets (those marketed to consumers) shouldn't be confused with pulsed electromagnetic-field therapy (PEMF), which involves brief exposures to much stronger electromagnetic fields. PEMF is effective for treating slow-healing fractures and shows promise for other conditions, including arthritis (Wien Klin Wochenschr, 2002; 114: 678-84; Injury, 2008; 39: 419-29).
WDDTY Volume 20 Issue 09