Have you had any direct experience of their use? Which ones are better? Here is one report I found which is inconclusive:
www.magneticexperience.com.au/magnetic_underlay.php
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Magnet therapy
What's the evidence?
Contents
Magnet therapy
What are the claims?
What's the evidence?
What about the products?
What are the alternatives?
The placebo effect
Electromagnetic therapy
The bottom line
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The big question is, do magnets really work? The answer is complicated because the more you look, the less everyone seems to know. There are some limited studies on static magnet therapy — including some that were double-blind (a highly respected method where neither patients nor researchers know who is using the trial therapy vs a placebo) — but the results are equivocal: for every positive result there’s a negative study that shows nothing.
The first study to cause a real stir was done at Baylor College of Medicine in Houston, Texas, in 1997. Participants were 50 patients suffering from post-polio syndrome who had been experiencing pain for at least a month. (This is a condition that can afflict adults who had polio as children; it manifests itself as muscular and arthritic pain and muscle weakness.)
The researchers asked them to rate their current rate of pain on a scale of one to 10. They then taped magnets (or placebos) for 45 minutes to the area where pain was triggered. The patients then rated their pain again on the 10-point scale.
The results were clear: of the 29 patients who had a magnet attached, 22 experienced an improvement in their pain levels, compared with just four out of the 21 who had the placebos. On average, the magnet patients experienced a 54% reduction in pain, compared to 12% for the placebo group.
This study has since been faulted — there was a disproportionate number of women in the trial group and the strength of the force exerted by the devices wasn’t measured exactly — but it was the first to make the medical community think there might be something to magnets. Another positive result came from the University of Virginia in 2001, where magnets were trialled as a treatment for the pain associated with fibromyalgia, a rheumatological syndrome associated with widespread pain, fatigue, fitful sleep, depression and anxiety, for which there are few effective treatments.
Two different magnetic underblankets (or placebos) were trialled by two groups of patients for six months. The results seemed to show that those using a ‘functional magnetic underlay’ (which provided whole-body exposure to a uniform magnetic field) had the greatest pain reduction, and researchers noted the effects were most likely cumulative. However, the results for each group weren’t different enough to be statistically significant.
Since then there have been a couple of other studies showing positive effects, including one this year — a small pilot study at the Harvard Medical School in Boston, which found that after four hours, magnets were effective (compared to placebos) at reducing the pain of osteoarthritis in the knee.
On the negative front, a study at the Veterans’ Affairs Medical Centre in Prescott, Arizona, in 2000 used magnets to treat chronic low-back pain by placing magnets (or placebos) on the affected area for six hours a day, three days a week for one week. It found they had no effect.
Nor did magnets make any difference in a study in 1997 as a treatment for plantar heel pain, when they were placed in moulded shoe insoles for four weeks. The group with magnetic insoles showed no greater improvement than the group with regular insoles.
A third study in 2002 at the Oklahoma College of Medicine, using magnetic disks (or placebos) strapped to the wrists for 45 minutes as a treatment for the pain associated with carpal tunnel syndrome, found no significant difference in effect between the magnets and the placebos. But the placebo group and the magnet group both reported an overall improvement in pain levels, indicating that the placebo effect was alive and well (see The placebo effect).
Overall there doesn’t appear to be a trend one way or the other, nor can the studies be easily compared. Some looked for an effect in a short space of time, while others involved weeks of use. Each used a different product and different-strength magnet. Each treated the pain associated with a different condition. The groups weren’t always gender-balanced (which is particularly important when studying pain and complementary medical treatments). As far as we can tell, none of these studies appears to have been replicated, nor is there a large enough body of scientific study to rule out the placebo effect
This page last reviewed September 2004