Magnet therapy

Magnet therapy, magnetic therapy, magnetotherapy or magnotherapy is a complementary and 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, typically NdFeB magnets has beneficial health effects. Magnetotherapy is considered pseudoscientific by its critics.

Description
The magnetic therapy industry totals sales of $300 million dollars per year in the United States and sells, often with explicit health claims, products such as magnetic bracelets and jewelry; magnetic straps for wrists, ankles, and the back; shoe insoles, mattresses, and magnetic blankets (blankets with magnets woven into the material); and even water that has been "magnetized".

Legal regulations
Marketing of the therapy as an effective treatment is heavily restricted by law in many jurisdictions. In the United States, for example, FDA regulations prohibit marketing a magnet therapy product that claims to treat any "significant" condition such as cancer, HIV, AIDS, asthma, arthritis, or rheumatism.

Efficacy
Recent studies conducted by Dr. Thomas Skalak of the University of Virginia's Department of Biomedical Engineering has shown that moderate strength magnetic fields can reduce inflammation from injury in rats.

A trial of magnetic therapy for the treatment of wrist pain from carpal tunnel syndrome and chronic low back pain did not find any health benefits above placebo.

Blinding the patients and the practitioners to the therapy is difficult since magnetization can be easily detected, e.g., by the attraction force it produces on ferrous objects.

A randomized controlled trial has found a statistically significant effect using non-magnetic and weak magnetic bracelets as controls against strong magnets. However, blinding was not perfect, as patients can assess the magnetic strength of the bracelets.

A study on humans of static field strengths up to 1 T found no effect on local blood flow.

Criticism
In certain cases, there is limited scientific theory under which the claimed benefits of magnet therapy might act. A 2002 National Science Foundation (NSF) report on public attitudes and understanding of science noted that magnet therapy is "not at all scientific." A randomized, double-blind, placebo controlled trial of 101 adults diagnosed with plantar heel pain carried out in year 2003 found no significant difference in outcome between use of active vs sham magnets. A number of vendors make unsupported claims about magnet therapy by using pseudoscientific and new-age language. Such claims are criticized by skeptics. Most criticisms include:


 * The typical magnet used produces insufficient magnetic field to have any effect on muscle tissue, bones, blood vessels, or organs.
 * Some manufacturers claim that the magnets help to circulate the blood by interacting with the iron in hemoglobin, a major component of red blood cells. However in its ionised form, iron is not ferromagnetic and would not be subject to magnetic attraction, save for magnetohydrodynamic forces due to its charge.
 * Others claim that the magnets can restore the body's theorized "electromagnetic energy balance", but no such balance is medically recognized.
 * There are claims that the south pole of a magnet acts differently on the body than the north pole.
 * Many of the websites that provide information and resources promoting the benefits of magnetic therapy belong to individuals and companies that profit from the sale of magnetic therapy products.