Magnet Therapy: Real Therapy or Wishful Thinking?
Magnetic knee, shoulder, and ankle pads, as well as insoles and mattress pads, are widely available and are touted as providing healing benefits. What is the scientific evidence to support the use of magnets?
Types of Magnet Therapy and Their UsesThe term magnet therapy refers to the use of static magnets placed directly on the body, generally over regions of pain. A static magnet is an ordinary permanent magnet, as opposed to an electromagnetic coil. Static magnets are either attached to the body by tape or encapsulated in specially designed products such as belts, wraps, or mattress pads. Static magnets come in various strengths. The units for measuring magnet strength are gauss and tesla. One tesla equals 10,000 gauss. A refrigerator magnet, for example, is around 50 gauss. Therapeutic magnets measure anywhere from 300 to 5,000 gauss.Therapeutic magnets come in 2 different types of polarity arrangements: unipolar magnets and alternating-pole devices. Magnets that have north on one side and south on the other are known, rather confusingly, as unipolar magnets. Bipolar or alternating-pole magnets are made from a sheet of magnetic material with north and south magnets arranged in an alternating pattern, so that both north and south face the skin. This type of magnet exerts a weaker magnetic field because the alternating magnets tend to oppose each other. There are many opinions on which one is better.
How Does Magnet Therapy Work?A commonly held misconception is that magnets attract the iron in the blood, thus moving the blood and stimulating circulation. However, because iron in the blood is bound to hemoglobin, it is not free to respond to a magnetic field. Static magnets could affect charged particles in the blood, nerves, and cell membranes or subtly alter biochemical reactions; however, biophysicists are skeptical that commercially available static magnets are strong enough to significantly affect the body. One trial found that commercially available static magnets have no effect on blood flow. Another found hints that static magnets might affect muscle metabolism, but further research is needed to sort out this possibility.