Magnetic medical devices are a $5 billion/year worldwide industry–an estimated $500 million/year in the United States alone–yet there’s little to no evidence that they work to relieve pain. Here’s more evidence that they don’t: “Magnetic shoe insoles did not effectively relieve foot pain among patients in a study, researchers report in the current issue of Mayo Clinic Proceedings.” Kudos to the doctors for publishing their negative results, even though the study’s materials were provided by Spenco Medical Corp., a company that makes magnetic medical devices. (Think the company will mention the study in their advertising?)

What’s interesting, though, is that the magnetic insoles provided relief to patients who believed they would: “…the results indicate that patients who strongly believed in magnets had pain relief even if they were given false magnets to wear.” More evidence that the placeo effect can provide real, positive, physical benefits if you only believe a medical treatment works.

I’ve had a long-standing problem with one of my ankles, and even though I don’t believe in magnetic therapy, I will admit that in my search for relief I spent $40 on a wrap-around sleeve that contains about six magnets that appear to be little more than kitchen magnets. It didn’t work. Yes, I should have listened to my rational side–or been more gullible.