Magnetic Therapy: Cure or Hoax?

September 16, 2008

Your local drugstore has “magnetic insoles” for sale that might help relieve foot pain. Your neighbor wears a magnetic bracelet and swears that it has cured his arthritis. On the internet, you can buy magnetic mattress pads, dog collars and knee wraps, all for alleviation of pain. A magnetic insole only costs $18. Should you spend your money on such “alternative treatments?” The simple answer is “No.”

Magnetic therapies have been around since at least the ancient Greeks, and survived through the Middle Ages. The most common claim for such therapies is that they promote blood flow and bring your body’s “electromagnetic field” into alignment with the Earth’s magnetic field. After all, the blood has a lot of iron in it, doesn’t it? Enough people fall for such claims to help make magnetic therapy a $300 million a year industry.

Read the fine print on the ads, however: “All these treatments are being studied. Nothing should be substituted for conventional treatment such as psychotherapy or prescribed medicines.” The truth is that the U.S. Food and Drug Administration has declared that magnets marketed with medical claims are considered to be medical devices requiring FDA medical clearance, and the FDA has not confirmed the efficacy of such claims.

There have been several studies of the effects of magnetic fields on the human body. The way you scientifically study such a claim is to run a “double blind” test, in which you compare two sets of test subjects, one with the magnetic product and one without. It is important that neither group knows which set they’re in, and the laboratory assistants running the test are likewise without this information. This eliminates the “placebo effect,” in which people who think something will help them can easily convince themselves that it does. Tests run as a true double blind have consistently discredited magnetic therapy claims. One study at Baylor seemed to show a slight improvement, but has been criticized as having used improper double blind controls.

One sure sign that magnetic therapies are scams are their repeated misuse of scientific terms. “Electromagnetism,” “electromotive force,” and “polarity agent effect” all sound very scientific, but in the context of the ads for such products they make no scientific sense. The fact is that the human body has an almost unmeasurably weak magnetic field. If it were otherwise, medical devices using much stronger magnetic fields, such as MRI’s (magnetic resonance imagery), would play havoc with your body. No, pulling scientific terms out of thin air does not mean your product is based on sound science.

So if you want to go around with magnets in your shoes, go right ahead. Just don’t expect any improvements in either your health or your pocketbook.