Introduction

Magnets have been used for health purposes for centuries. Static, or permanent, magnets are widely marketed for pain control and are considered part of complementary and alternative medicine (CAM). This fact sheet provides an overview of magnets and summarizes current scientific knowledge about their effects on pain.

Key Points

• Magnets in products such as magnetic patches and disks, shoe insoles, bracelets, and mattress pads are used for pain in the foot, wrist, back, and other parts of the body.
• Preliminary scientific studies of magnets for pain have produced mixed results. Overall, there is no convincing scientific evidence to support claims that magnets can relieve pain of any type. Some studies, including a recent National Institutes of Health (NIH) clinical trial for back pain, suggest the possibility of a small benefit from using magnets for pain. However, the majority of rigorous studies have found no effect on pain. More research on magnets for pain is needed before reaching any firm conclusion.
• Magnets are generally considered safe when applied to the skin, but they may not be safe for some people, such as those who use medical devices like pacemakers or defibrillators, as magnets may interfere with the device.
• Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

About Magnets

A magnet produces a measurable force called a magnetic field. Static magnets have magnetic fields that do not change (unlike another type called electromagnets, which generate magnetic fields only when electrical current flows through them). Magnets are usually made from metals (such as iron) or alloys (mixtures of metals, or of a metal and a nonmetal).

Magnets come in different strengths, often measured in units called gauss (G) or, alternatively, units called tesla (1 tesla = 10,000 G). Magnets marketed for pain usually claim strengths of 300 to 5,000 G—many times stronger than the Earth’s magnetic field (about 0.5 G) and much weaker than the magnets used for MRI machines (approximately 15,000 G or higher).

Various products with magnets in them are marketed for health purposes, including shoe insoles, bracelets and other jewelry, mattress pads, bandages, headbands, and belts. These products are often placed in contact with painful areas of the body with the goal of providing relief.

History of Magnets for Health Uses

Magnets have been used for many centuries for a variety of health purposes. By various accounts, magnets were discovered when people first noticed the presence of naturally magnetized stones, also called lodestones. By the third century A.D., Greek physicians were using magnetic rings to treat arthritis and magnetized pills made of amber to stop bleeding. In the Middle Ages, doctors used magnets to treat gout, arthritis, poisoning, and baldness; to clean wounds; and to retrieve arrowheads and other iron-containing objects from the body.

In the United States, magnetic devices (such as hairbrushes and insoles), magnetic ointments, and clothes with magnets attached came into wide use after the Civil War, especially in some rural areas where few doctors were available. Healers claimed that magnetic fields existed in the blood, and that people became ill when their magnetic fields were depleted. Thus, healers marketed magnets as a means of replenishing these magnetic fields. Magnets were promoted as cures for a wide range of health conditions, including paralysis, headache, backache, sleeplessness, upset stomach, and liver and kidney problems.

The use of magnets to treat medical problems remained popular well into the 20th century. Today, magnets are used for many different types of pain, including foot pain and back pain from conditions such as arthritis and fibromyalgia.

What the Science Says

What Studies Have Shown

Overall, the scientific evidence does not support the use of magnets for pain relief. Preliminary studies looking at different types of pain—such as knee, hip, wrist, foot, back, and pelvic pain—have had mixed results. Some of these studies, including a recent NIH-sponsored clinical trial that looked at back pain in a small group of people, have suggested a benefit from using magnets. The majority of rigorous trials, however, have found no effect on pain.

Some research results suggest that effects may depend on the type of pain treated. For example, results from a few studies suggest that magnets might provide some relief specifically from osteoarthritis pain. Effects may also depend on the type and strength of the magnets used, the frequency of use, and the length of time the magnet was applied during the study.

Many studies were not high-quality because they included a small number of participants, were too short, and/or were poorly designed. More rigorous research is needed before reaching any firm conclusions about the effectiveness of magnets for pain.

Challenges Facing Researchers

Researchers face challenges when studying magnets in clinical trials:

• Something other than the magnet may relieve a study participant’s pain. For example, relief could come from a placebo effect or from a warm bandage or cushioned insole that holds the magnet in place.
• It can be difficult to design a sham magnet that participants cannot distinguish from an active magnet. If participants know whether they are using an active magnet, study findings may be less reliable.
• It is possible that the magnetic properties of low-strength magnets, which are sometimes used as shams, can actually have a therapeutic effect.
• Opinions differ about how to administer magnet therapy, including what strength magnet to use, where to place the magnets on the body, and how long to use them. These factors have not been fully studied in humans. Clinical trials that look at these factors are needed.

How Magnets Might Work

No scientific theory or manufacturer claim about how magnets might work has been conclusively proven. Although some preliminary research has been conducted in animals and in small clinical trials, the mechanisms by which magnets might affect the human body are not yet known.

Scientific researchers and magnet manufacturers have proposed that magnets might work by:

• Changing how nerve cells function and blocking pain signals to the brain
• Restoring the balance between cell death and growth
• Increasing the flow of blood and the delivery of oxygen and nutrients to tissues
• Increasing the temperature of the area of the body being treated.

Findings from preliminary studies in healthy people—including one study funded by NIH—suggest that magnets may not affect blood flow or nerve function.

Side Effects and Risks

Magnets may not be safe for some people to use, including those who:

• Use a medical device such as a pacemaker, defibrillator, or insulin pump, because magnets may interfere with the functioning of the medical device
• Have a wound that has not healed.

Otherwise, magnets are generally considered safe when applied to the skin. Reports of side effects or complications have been rare.

It is important not to use magnets in place of proven treatments for serious medical conditions. Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

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