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?
The 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 300-5,000 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.
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.
Static magnets have not shown too much promise in studies, but the evidence is not yet conclusive. For example, a trial of 119 people with fibromyalgia compared 2 commercially available magnetic mattress pads against sham treatment and no treatment. Sham mattresses still had magnets in them and they matched the appearance of the mattresses used in the test treatment, but the magnets had little or no force. Participants in the treatment groups, especially the group with negative polarity magnets, showed a hint of greater improvement of pain symptoms. However, the differences between real treatment and sham or no treatment generally failed to reach statistical significance. This outcome means that the benefits seen could have been due to chance.
Other studies have evaluated magnet therapy for a variety of conditions, with mixed results. Some conditions include:
In a review of 25 studies, magnetic therapy showed little evidence of symptom improvement in people with chronic pain regardless of the cause. Again, while there are some studies that show magnet therapy can be helpful for treating many conditions, this is an area that needs further research since the overall evidence is conflicting.
So, are magnets really so attractive when it comes to alleviating pain? You may experience some benefit, but it is not clear whether the treatment will cause any improvement above and beyond what a placebo could do. Only further scientific study can answer this question.
Additionally, if you have a pacemaker or other implantable medical device, such as a defibrillator, insulin pump, or chemotherapy infusion pump, avoid using magnets. They may interfere with the function of these devices.
Family Doctor—American Academy of Family Physicians
National Center for Complementary and Integrative Health
Canadian Interdisciplinary Network for CAM Research
Alfano AP, Taylor AG, Foresman PA, et al. Static magnetic fields for treatment of fibromyalgia: a randomized controlled trial. J Altern Complement Med. 2001;7(1):53-64.
Atef MM, Adb el-Baset MS. el-Kareem A, el-Kareem A, Aida S, Fadel MA.. Effects of a static magnetic field on haemoglobin structure and function. Int J Biol Macromol. 1995;17(2):105-111.
Cervical radicular pain and radiculopathy. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116531/Cervical-radicular-pain-and-radiculopathy. Updated December 2, 2014. Accessed January 20, 2017.
Diabetic peripheral neuropathy. EBSCO Plus DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T115259/Diabetic-peripheral-neuropathy. Updated November 14, 2016. Accessed January 20, 2017.
Fibromyalgia. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T116339/Fibromyalgia. Updated December 1, 2016. Accessed January 20, 2017
Magnet therapy. EBSCO Natural and Alternative Treatments website. Available at: http://www.ebscohost.com/biomedical-libraries/natural-alternative-treatments. Updated October 11, 2016. Accessed January 20, 2016.
Magnet therapy. Memorial Sloan Kettering Cancer Center website. Available at: https://www.mskcc.org/cancer-care/integrative-medicine/herbs/magnet-therapy. Updated May 11, 2011. Accessed January 20, 2017.
Magnets for pain relief. National Center for Complementary and Integrative Health website. Available at: https://nccih.nih.gov/health/magnet/magnetsforpain.htm. Updated February 2013. Accessed January 20, 2017.
Pittler MH, Brown EM, Ernst E. Static magnets for reducing pain: systematic review and meta-analysis of randomized trials. CMAJ. 2007;177(7):736-742.
Last reviewed January 2017 by Michael Woods, MD, FAAP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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