Magnet therapy

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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 magnets has beneficial health effects. Magnet therapy is considered pseudoscientific due to both physical and biological implausibility, as well as a lack of any established effect on health or healing. Hemoglobin is weakly diamagnetic, and is repulsed by magnetic fields. The magnets used are many orders of magnitude too weak to have any measurable effect on blood flow.

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Description

Magnet therapy is the application of the magnetic field of electromagnetic devices or permanent static magnets to the body for purported health benefits.

The modern magnet 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 any therapy as effective treatment for any condition is heavily restricted by law in many jurisdictions unless all such claims are scientifically validated. In the United States, for example, FDA regulations prohibit marketing any magnet therapy product using medical claims, as such claims are unfounded.

Efficacy

Blinding of patients and assessors to the therapy is difficult since magnetization can be easily detected, for instance, by the attraction force it produces on ferrous objects. Incomplete or insufficient blinding tends to exaggerate treatment effects, particularly where any such effects are small. Several studies have been conducted in recent years to investigate what, if any, role static magnetic fields may play in health and healing.

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

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.

A 2003 Cochrane Review of carpal tunnel syndrome treatments found no improvement in symptoms over placebo or control.

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 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 could assess the magnetic strength of the bracelets.

A 2007 study suggested that application of 10 or 70, but not 400 mT, static magnetic fields reduced histamine-induced edema formation in rats.

Criticism

A 2002 NSF report on public attitudes and understanding of science noted that magnet therapy is "not at all scientific." A number of vendors make unsupported claims about magnet therapy by using pseudoscientific and new-age language. Such claims are unsupported by the results of scientific and clinical studies. Most criticisms include: