Magnet therapy, magnetic therapy, or magnotherapy is a pseudoscientific alternative medicine practice involving the use of static magnetic fields. Practitioners claim that subjecting certain parts of the body to magnetostatic fields produced by permanent magnets has beneficial health effects. These physical and biological claims are unproven and no effects on health or healing have been established. Although hemoglobin, the blood protein that carries oxygen, is weakly diamagnetic (when oxygenated) or paramagnetic (when deoxygenated) the magnets used in magnetic therapy are many orders of magnitude too weak to have any measurable effect on blood flow.
Methods of application
Magnet therapy is the application of the magnetic field of electromagnetic devices or permanent static magnets to the body for purported health benefits. Some believers assign different effects based on the orientation of the magnet; under the laws of physics, magnetic poles are symmetric.
Products include magnetic bracelets and jewelry; magnetic straps for wrists, ankles, knees, and back; shoe insoles; mattresses; magnetic blankets (blankets with magnets woven into the material); magnetic creams; magnetic supplements; plasters/patches and water that has been “magnetized”. Application is usually performed by the patient.
Purported mechanisms of action
Perhaps the most common suggested mechanism is that magnets might improve blood flow in underlying tissues. The field surrounding magnet therapy devices is far too weak and falls off with distance far too quickly to appreciably affect hemoglobin, other blood components, muscle tissue, bones, blood vessels, or organs. A 1991 study on humans of static field strengths up to 1 T found no effect on local blood flow. Tissue oxygenation is similarly unaffected. Some practitioners claim that the magnets can restore the body’s hypothetical “electromagnetic energy balance”, but no such balance is medically recognized. Even in the magnetic fields used in magnetic resonance imaging, which are many times stronger, none of the claimed effects are observed. If the body were meaningfully affected by the weak magnets used in magnet therapy, MRI would be impractical.