Magnet therapy, although enjoying a recent upsurge in popularity, is not new. The idea that magnets might contain healing powers are as old as magnets themselves. The first modern reference is by Swiss physician, Paracelsus, who used magnets to treat epilepsy and other conditions in the early sixteenth century. Magnetic therapy was then given a boost in the mid-eighteenth century by Franz Mesmer, who coined the term “animal magnetism” to refer to the magnetic force within living organisms. Magnetic healing survived into the twentieth century, but decreased sharply with the advent of scientific biomedicine. In the 1990’s, however, with the increasing popularity of alternative and unscientific healing modalities, magnet therapy has experienced a resurgence.
There are now thousands of companies selling magnets of various strengths, sizes, and shapes with testimonials and health claims including pain relief, improved circulation and wound healing, relief from arthritis, and improved athletic performance. Proposed mechanisms include improved circulation by either attracting the iron ions at the center of hemoglobin molecules, or improving oxygenation of tissues.
The Skeptical Viewpoint
Magnet therapy represents just the latest in an endless line of snake oil, complete with the full list of unsubstantiated claims and testimonials about a wide variety of health claims. All of the proposed mechanisms for the effects of magnets are either at odds with physics, or has been disproven through direct experimentation. For example, the static magnetic field of most magnets sold for medical use have a field strength at their surface of about 500 Gauss. At one centimeter from the surface, however, the field strength drops off to only 1 Gauss, which is the field strength of the Earth’s magnetic field. Another centimeter and the field strength is negligible. This is because electromagnetic fields fall off rapidly with distance. Even if such a magnet were placed directly over a painful wrist, therefore, it would be several centimeters away from the joint and the source of pain.
Some have proposed that the magnetic fields reduce pain by inhibiting nerve conduction. In order to reduce nerve conduction by 10%, however, a 24 Tesla static magnetic field would be required. One Tesla equals 10,000 Gauss. Static magnets, therefore, produce 1/240,000 the field necessary to accomplish a 10% decrease in nerve conduction 1cm from their surface. The claim that magnetic fields improve blood flow are similarly unlikely. For example, a 10 Tesla magnetic field would be required to have a 0.2% effect on blood perfusion pressure.
What about the clinical evidence? Well, proponents have touted the study conducted by researchers at Baylor College of Medicine in Houston, who conducted a double-blind test comparing the effects of magnets and sham magnets on the knee pain of 50 patients with post polio pain. The 29 who received an active magnet reported a significantly greater reduction in pain than the 21 treated with a sham magnet. This study is contradicted by another clinical study, however. Researchers at the New York College of Podiatric Medicine conducted a 4 week trial of patients with heel pain; 19 patients wore a molded insole containing a magnetic foil, while 15 patients wore the same type of insole with no magnetic foil. In both groups, 60% reported improvement, and therefore the magnetic foil conveyed no benefit. Both of these studies were small and came to opposite conclusions. Clearly, more, larger, and better designed studies are necessary to reach a firm clinical conclusion.
Why, then, do so many people swear by magnets? The mere fact that many people believe they are being helped by magnets is not compelling evidence that they work. Thousands have given testimonials extolling the healing power of treatments and devices that were later discovered to be either clear frauds, or harmful concoctions. For example, around the turn of the century it was popular to sell radioactive solutions as a healing tonic, and thousands swore by them even as they were slowly killing them.
Apparent benefit can be explained by many factors, such as the placebo effect. People will usually perceive some improvement in their health or symptoms just by taking action to help themselves. Also, many ailments are self-limiting, meaning that they will get better by themselves. Many people with temporary back pain which gets better on its own will therefore credit the magnets they used with their recovery. Also, many of the magnet products are contained in wraps or bandages, or sown into pads to sleep on or insoles for shoes. There is likely to be some benefit just from having a bandage around an aching elbow, or from the extra support provided by the sleeping pad or insole.
In the absence of adequate clinical evidence, however, companies continue to sell magnets with unsubstantiated claims. One such company, Magnetherapy, inc. was fined $30,000 for making health claims regarding their magnets, and signed a voluntary agreement to stop making such claims. Most companies, however, evade regulations by not making specific claims. Rather, they provide testimonials or make vague statements which avoid specific health claims.
References:
Ramey DW. Magnetic and Electromagnetic Therapy. The Scientific Review of Alternative Medicine, 1998 vol.2, No. 1, pg 13-19
Barrett, Stephen. Magnet Therapy. Quackwatch (http://www.quackwatch.com/04ConsumerEducation/QA/magnet.html)
Livingston, James D. Magnetic Therapy: Plausible Attraction. Skeptical Inquirer, 1998 vol. 22, No 4 pg 25-30 (http://www.csicop.org/si/9807/magnet.html)