A simple treatment for many type 2 diabetics who have painful diabetic neuropathy of the feet is a magnetic insole slipped into the shoe of the affected foot (or feet). Researchers have tested both stationary magnets (magnets that emit a constant magnetic field) and pulsed magnets (magnets that emit bursts of energy hundreds or thousands of times per second), shaped into insoles that easily fit inside shoes. The burning question, if you'll forgive the pun, is whether they actually work.
An early study of magnetic insoles was practically guaranteed to fail. Participants were given insoles that might or might not have been magnetic, told to wear them however they liked, and sent a survey to be filled out two months later. People with many different kinds of foot pain were recruited for the study, and almost none of the kinds of foot pain seemed to be helped by the magnetic insoles--except diabetic neuropathy.
A more recent clinical trial involved 225 volunteers, all of whom had diabetic neuropathy, half of whom were given pulsating magnetic shoe insoles. In this study about 44 per cent of insole uses reported relief, although itching was more likely to be stopped than pain. The study organizers believe that a stronger magnet than used in their study might be more effective for relieving neuropathy pain.
Winemiller MH, Billow RG, Laskowski ER, Harmsen WS. Effect of magnetic vs sham-magnetic insoles on plantar heel pain: a randomized controlled trial [published correction appears in JAMA. 2004;291:46]. JAMA. 2003;290:1474-1478.
Weintraub MI, Herrmann DN, Smith AG, Backonja MM, Cole SP. Pulsed electromagnetic fields to reduce diabetic neuropathic pain and stimulate neuronal repair: a randomized controlled trial. Arch Phys Med Rehabil. 2009 Jul;90(7):1102-9.