Magnet therapy may attract people looking to ease their pain simply and inexpensively, but according to a new study published recently in the online journal PLOS ONE, magnetic wrist straps don't work for rheumatoid arthritis (RA) pain or stiffness. The study also confirmed that copper bracelets don’t work either.

In the study, the researchers had 70 RA patients wear four different devices, each for five weeks at time: a magnetic wrist strap, a copper bracelet (used as a “placebo,” or control, device, since previous studies indicate that they don’t provide a benefit), a wrist strap with a very weak magnetic field (another control device) and a demagnetized strap (a third control device). Neither the participants nor the researchers knew which devices were being worn when.

“In my research I set out to confuse the heck out of participants so they couldn't tell which device was real and which was a placebo,” says lead study author Stewart Richmond, PhD, research fellow at the University of York, in England.

The results showed no improvements, beyond the placebo effect, for the magnetic bands or copper bracelets in any of the outcomes measured, which included joint swelling and tenderness, physical function, and inflammation (measured by blood tests). A previous study by the same author found no value for these devices in treating osteoarthritis (OA).

“When the findings of my second trial came in, the thing I found most surprising was the remarkable consistency of results,” says Richmond. “Normally you would expect a fair degree of “noise” in the data, but with the study that has just been published, the findings were pretty clear: the devices you can purchase in shops were no better than placebo.”

Eric Matteson, MD, chair of rheumatology at Mayo Clinic, in Rochester, Minn., called the study “very good evidence about their lack of efficacy.”

The results did not surprise Robin Miller, MD, an integrative medicine physician, currently in private practice. “In my experience, these devices do not work any better than placebo,” she says.

Still, like many ineffective treatments, some people will be tempted to try them. "People are always looking for benign treatments, and for people in chronic pain, easy, benign treatments are especially alluring," says Dr. Miller.

But why copper, and why magnets?

“The basic idea with copper bracelets is that our bodies are somehow deficient in the copper we absorb from our diet, and that copper will be leached from the bracelets into the skin and help to ease joint inflammation,” Richmond says. “This stems back to the theory of metallotherapy [from] the mid-19th century, which was debunked through early clinical research.”

With magnets, “The basic idea is that magnets placed against the skin influence the circulation of iron in the blood, which helps deliver nutrients to the joints,” explains Richmond. “Again, the more you look into these theories, the more you realize that they are just bunkum: Iron in the blood is not ferromagnetic [attracted to magnets], and commercially available magnetic wrist strap will not alter blood flow. If such theories were valid, the human body would explode when placed in a MRI machine. Thankfully, this doesn't happen.”

People may be tricked into thinking that devices such as these work because of what Richmond calls a very common logical fallacy. “If people generally try out a new treatment when their symptoms are at their worst, and their symptoms subside, they think ‘Wow! It really worked!’” he says. “If people with chronic conditions were encouraged to begin using these devices when their symptoms were mildest, then the reverse situation would be true: People would report that the devices were harmful.”

Dr. Matteson notes, “As the authors state, the devices hold allure because they are safe and inexpensive, but as pointed out [in the study], the risk is that patients might use them in lieu of effective treatment, rather than as an ‘add on.’”