Magnets for Pain
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.
NCCAM-Funded
Research
Projects on magnets supported by the National Center for
Complementary and Alternative Medicine (NCCAM) include the
following:
References
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