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Questions and Answers About
Using Magnets
To Treat Pain
http://nccam.nih.gov/health/magnet/magnet.htm
Treatment Information
On this page
· Introduction
·
Key Points
1.
What are magnets?
2.
Is the use of magnets
considered conventional medicine or complementary and alternative
medicine?
3.
What is the history of
the discovery and use of magnets to treat pain?
4.
How common is the use of
magnets to treat pain?
5.
What are some examples
of theories and beliefs about magnets and pain?
6.
How are static magnets
used in attempts to treat pain?
7.
How are electromagnets
used in attempts to treat pain?
8.
What is known from the
scientific evidence about the effectiveness of magnets in treating
pain?
9.
Are there scientific
controversies associated with using magnets for pain?
10.
Have any side effects or
complications occurred from using magnets for pain?
11.
What should consumers
know if they are considering using magnets to treat pain?
12.
Is the National Center
for Complementary and Alternative Medicine (NCCAM) funding research
on magnets for pain and other diseases and conditions?
·
For More Information
·
References
· Appendix I: Research on
Theories and Beliefs On How Magnets Might Relieve Pain
·
Appendix II: General and
Systematic Reviews on CAM Magnetic Therapy for Pain Published From
August 1999 to August 2003
·
Appendix III: Reports on
Randomized Clinical Trials of Magnetic Therapy for Pain From January
1997 to March 2004
Introduction
Magnets are objects that
produce a type of energy called magnetic fields. Magnets are widely
marketed to treat or ease the symptoms of various diseases and
conditions, including pain. This Research Report provides an overview of
the use of magnets for pain, summarizes current scientific knowledge
about their effectiveness for this purpose, and suggests additional
sources of information.
Key Points
· The vast majority of
magnets marketed to consumers to treat pain are of a type called
static (or permanent) magnets, because the resulting magnetic fields
are unchanging. The other magnets used for health purposes are
called electromagnets, because they generate magnetic fields only
when electrical current flows through them. Currently,
electromagnets are used primarily under the supervision of a health
care provider or in clinical trials.
· Scientific research so
far does not firmly support a conclusion that magnets of any type
can relieve pain. However, some people do experience some relief.
Various theories have been proposed as to why, but none has been
scientifically proven (see Question 5).
· Clinical trials in this
area have produced conflicting results (see Question 8). Many
concerns exist regarding the quality and rigor of the studies
conducted to date, leading to a call for additional, higher quality,
and larger studies.
· The U.S. Food and Drug
Administration (FDA) has not approved the marketing of magnets with
claims of benefits to health (such as "relieves arthritis pain").
The FDA and the Federal Trade Commission (FTC) have taken action
against many manufacturers, distributors, and Web sites that make
claims not supported scientifically about the health benefits of
magnets.
· It is important that
people inform their health care providers about any therapy they are
currently using or considering, including magnets. This is to help
ensure a safe and coordinated course of care.
1.
What are magnets?
Magnets are objects that
produce a type of energy called magnetic fields. All magnets possess a
property called polarity--that is, a magnet's power of attraction is
strongest at its opposite ends, usually called the north and south
poles. The north and south poles attract each other, but north repels
north and south repels south. All magnets attract iron.
Magnets come in different
strengths, most often measured in units called gauss (G). For comparison
purposes, the Earth has a magnetic field of about 0.5 G; refrigerator
magnets range from 35 to 200 G; magnets marketed for the treatment of
pain are usually 300 to 5,000 G; and MRI (magnetic resonance imaging)
machines widely used to diagnose medical conditions noninvasively
produce up to 200,000 G.1
The vast majority of magnets
marketed to consumers for health purposes (see the box below) are of a
type called static (or permanent) magnets. They have magnetic fields
that do not change.
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Examples of Products Using Magnets |
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· Shoe insoles
· Heel inserts
· Mattress pads
· Bandages |
· Belts
· Pillows and
cushions
· Bracelets and other
jewelry
· Headwear |
The other magnets used for
health purposes are called electromagnets, because they generate
magnetic fields only when electrical current flows through them. The
magnetic field is created by passing an electric current through a wire
coil wrapped around a magnetic core. Electromagnets can be pulsed--that
is, the magnetic field is turned on and off very rapidly.
2. Is the use of magnets
considered conventional medicineMedicine as practiced by holders of M.D.
(medical doctor) or D.O. (doctor of osteopathy) degrees and by their
allied health professionals such as physical therapists, psychologists,
and registered nurses. or complementary and alternative medicine?
Conventional medicine and
complementary and alternative medicine (CAM)A group of diverse medical
and health care systems, practices, and products that are not presently
considered to be part of conventional medicine. Complementary medicine
is used together with conventional medicine, and alternative medicine is
used in place of conventional medicine. are defined in the box below.
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About
CAM and Conventional Medicine
Complementary and
alternative medicine (CAM) is a group of various medical and
health care systems, practices, and products that are not
presently considered to be part of conventional medicine.
Conventional medicine is medicine as practiced by holders of
M.D. (medical doctor) or D.O. (doctor of osteopathy) degrees and
by allied health professionals, such as physical therapists,
psychologists, and registered nurses. To find out more, see the
NCCAM fact sheet "What Is Complementary and Alternative
Medicine?"
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There are some uses of
electromagnets within conventional medicine. For example, scientists
have found that electromagnets can be used to speed the healing of bone
fractures that are not healing well.2,3 Even more commonly,
electromagnets are used to map areas of the brain. However, most uses of
magnets by consumers in attempts to treat pain are considered CAM,
because they have not been scientifically proven and are not part of the
practice of conventional medicine.
3. What is the history of the
discovery and use of magnets to treat pain?
Magnets have been used for
many centuries in attempts to treat pain.a By various
accounts, this use began when people first noticed the presence of
naturally magnetized stones, also called lodestones. Other accounts
trace the beginning to a shepherd noticing that the nails in his sandals
were pulled out by some stones. By the third century A.D., Greek
physicians were using rings made of magnetized metal to treat arthritis
and pills made of magnetized amber to stop bleeding. In the Middle Ages,
doctors used magnets to treat gout, arthritis, poisoning, and baldness;
to probe and 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 salves, and
clothes with magnets applied 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, organs, or elsewhere
in the body and that people became ill when their magnetic fields were
depleted. Thus, healers marketed magnets as a means of "restoring" these
magnetic fields. Magnets were promoted as cures for paralysis, asthma,
seizures, blindness, cancer, and other conditions. The use of magnets to
treat medical problems remained popular well into the 20th century. More
recently, magnets have been marketed for a wide range of diseases and
conditions, including pain, respiratory problems, high blood pressure,
circulatory problems, arthritis, rheumatism, and stress.
a Sources for this
historical discussion include references 1, 4, and 5.
4. How common is the use
of magnets to treat pain?
A 1999 survey of patients who
had rheumatoid arthritis, osteoarthritis, or fibromyalgia and were seen
by rheumatologists reported that 18 percent had used magnets or copper
bracelets, and that this was the second-most-used CAM therapy by these
patients, after chiropractic.6 One estimate places Americans'
spending on magnets to treat pain at $500 million per year; the
worldwide estimate is $5 billion.7 Many people purchase
magnets in stores or over the Internet to use on their own without
consulting a health care provider.
5. What are some examples of
theories and beliefs about magnets and pain?
Some examples of theories and
beliefs about using magnets to treat pain are listed below. These range
from theories proposed by scientific researchers to claims made by
magnet manufacturers. It is important to note that while the results for
some of the findings from the scientific studies have been intriguing,
none of the theories or claims below has been conclusively proven. For
the following, summaries of research from peer-reviewed medical and
scientific journals appear in Appendix I:
· Static magnets might
change how cells function.
· Magnets might alter or
restore the equilibrium (balance) between cell death and growth.
· Because it contains
iron, blood might act as a conductor of magnetic energy. Static
magnets might increase the flow of blood and, therefore, increase
the delivery of oxygen and nutrients to tissues.
· Weak pulsed
electromagnets might affect how nerve cells respond to pain.
· Pulsed electromagnets
might change the brain's perception of pain.
· Electromagnets might
affect the production of white blood cells involved in fighting
infection and inflammation.
Here are two other theories
and beliefs:
· Magnets might increase
the temperature of the area of the body being treated.
· "Magnetizing" or
"re-magnetizing" drinking water or other beverages might allow them
to hydrate the body better and flush out more "toxins" than ordinary
drinking water.
6. How are static magnets
used in attempts to treat pain?
Static magnets are usually
made from iron, steel, rare-earth elements, or alloys. Typically, the
magnets are placed directly on the skin or placed inside clothing or
other materials that come into close contact with the body. Static
magnets can be unipolar (one pole of the magnet faces or touches the
skin) or bipolar (both poles face or touch the skin, sometimes in
repeating patterns).8 Some magnet manufacturers make claims
about the poles of magnets--for example, that a unipolar design is
better than a bipolar design, or that the north pole gives a different
effect from the south pole. These claims have not been scientifically
proven.1,9
A small number of rigorous
scientific studies have examined the efficacy of static magnets in
treating pain. This evidence is discussed in Question 8 and Appendices
II and III.
7. How are electromagnets
used in attempts to treat pain?
Electromagnets were approved
by the FDA in 1979 to treat bone fractures that have not healed well.2,3
Researchers have been studying electromagnets for painful conditions,
such as knee pain from osteoarthritis, chronic pelvic pain, problems in
bones and muscles, and migraine headaches.3,9-12 However,
these uses of electromagnets are still considered experimental by the
FDA and have not been approved. Currently, electromagnets to treat pain
are being used mainly under the supervision of a health care provider
and/or in clinical trials.
An electromagnetic therapy
called TMS (transcranial magnetic stimulation) is also being studied by
researchers. In TMS, an insulated coil is placed against the head, near
the area of the brain to be examined or treated, and an electrical
current generates a magnetic field into the brain. Currently, TMS is
most often used as a diagnostic tool, but research is also under way to
see whether it is effective in relieving pain.13,14 A type of
TMS called rTMS (repetitive TMS) is believed by some to produce longer
lasting effects and is being explored for its usefulness in treating
chronic pain, facial pain, headache, and fibromyalgia pain.15,16
A related form of electromagnetic therapy is rMS (repetitive magnetic
stimulation). It is similar to rTMS except that the magnetic coil is
placed on or near a painful area of the body other than the head. This
therapy is being studied as a treatment for musculoskeletal pain.17,18
8. What is known from the
scientific evidence about the effectiveness of magnets in treating pain?
Overall, the research
findings so far do not firmly support claims that magnets are effective
for treatment of pain.
Findings from Reviews of
Scientific Studies
Reviews take a broad look at the findings from a group of individual
research studies. Such reviews are usually either a general review, a
systematic review, or a meta-analysis. There are not many reviews
available on CAM uses of magnets to treat pain. Appendix II provides
examples of six reviews published from August 1999 through August 2003
in English in the National Library of Medicine's MEDLINE database.
· Often, these reviews
compared what is known from the clinical trials of magnets for
painful conditions to what is known from conventional treatments or
from other CAM treatments for the same condition(s).
· One review found that
static magnetic therapy The use of magnets or magnetic devices for
health purposes. may work for certain conditions but that there is
not adequate scientific support to justify its use.1
· Three reviews found
that electromagnetic therapy showed promise for the treatment of
some, but not all, painful conditions, and that more research is
needed.9,19,20 One of these reviews also looked at two
randomized clinical trials (RCTs) of static magnets.9 One
reported significant pain relief in subjects using magnets, but the
other did not.
· Another review
concluded that TMS has an effect on the central nervous system that
might relieve chronic pain and, therefore, should be studied
further.14
· The remaining review
found no studies on magnets for neck pain and stated that rigorous
studies are much needed.21
· It is important to note
that the reviews pointed out problems with the rigor of most
research on magnets for pain.9,14,19,20 For example, many
of the clinical trials involved a very small number of participants,
were conducted for very short durations (e.g., one study applied a
magnet a total of one time for 45 minutes), and/or lacked a placebo
or sham group for comparison to the magnet group.19,20
Thus, the results of many trials may not be truly meaningful. Most
reviews stated that more and better quality research is needed
before magnets' effectiveness can be adequately judged.
Findings from Clinical Trials
The studies in Appendix III give an overview of scientific research from
15 RCTs published in English from January 1997 through March 2004 and
cataloged in the National Library of Medicine's MEDLINE database. These
trials studied CAM uses of static magnets or electromagnets for various
kinds of pain.
· The results of trials
of static magnets have been conflicting. Four of the nine static
magnet trials analyzed found no significant difference in pain
relief from using a magnet compared with sham treatment or usual
medical care.7,8,22,23 Four trials did find a significant
difference, with greater benefit seen from magnets.24-27
The remaining trial compared only a weaker strength magnet to a
stronger magnet, and found benefit from both (there was no
difference between groups in how much benefit).28
· Trials of
electromagnets yielded more consistent results. Five out of six
trials found that these magnets significantly reduced pain.10,11,17,18,29
The sixth found a significant benefit to physical function from
using electromagnets, but not to pain or stiffness.30
· Some study authors
suggested that a placebo effect could have been responsible for the
pain relief that occurred from magnets.22,30
· While criticizing many
of these studies, it is fair to say that testing magnets in clinical
trials has presented challenges. For example, it can be difficult to
design a sham magnet that appears exactly like an active magnet.
Also, there has been concern about how many participants have tried
to determine whether they have been assigned an active magnet (for
example, by seeing whether a paperclip would be attracted to it);
this knowledge could affect how meaningful a trial's results are.
9. Are there scientific
controversies associated with using magnets for pain?
Yes, there are many
controversies. Examples include:
· The mechanism(s) by
which magnets might relieve pain have not been conclusively
identified or proven.
· Pain relief while using
a magnet may be due to reasons other than the magnet. For example,
there could be a placebo effect or the relief could come from
whatever holds the magnet in place, such as a warm bandage or a
cushioned insole.22,24
· Opinions differ among
manufacturers, health care providers who use magnetic therapy, and
others about which types of magnets (strength, polarity, length of
use, and other factors) should be used and how they should be used
in studies to give the most definitive answers.
· Actual magnet strengths
can vary (sometimes widely) from the strengths claimed by
manufacturers. This can affect scientists' ability to reproduce the
findings of other scientists and consumers' ability to know what
strength magnet they are actually using.26,31,32
10. Have any side effects or
complications occurred from using magnets for pain?
The kinds of magnets marketed
to consumers are generally considered to be safe when applied to the
skin.7 Reports of side effects or complications have been
rare. One study reported that a small percentage of participants had
bruising or redness on their skin where a magnet was worn.33
Manufacturers often recommend
that static magnets not be used by the following people1:
· Pregnant women, because
the possible effects of magnets on the fetus are not known.
· People who use a
medical device such as a pacemaker, defibrillator, or insulin pump,
because magnets may affect the magnetically controlled features of
such devices.
· People who use a patch
that delivers medication through the skin, in case magnets cause
dilation of blood vessels, which could affect the delivery of the
medicine. This caution also applies to people with an acute sprain,
inflammation, infection, or wound.
There have been rare cases of
problems reported from the use of electromagnets. Because at present
these are being used mainly under the supervision of a health care
provider and/or in clinical trials, readers are advised to consult their
provider about any questions.
11. What should consumers
know if they are considering using magnets to treat pain?
· It is important that
people inform all their health care providers about any therapy they
are using or considering, including magnetic therapy. This is to
help ensure a safe and coordinated plan of care.
· In the studies that did
find benefits from magnetic therapy, many have shown those benefits
very quickly. This suggests that if a magnet does work, it should
not take very long for the user to start noticing the effect.
Therefore, people may wish to purchase magnets with a 30-day return
policy and return the product if they do not get satisfactory
results within 1 to 2 weeks.
· If people decide to use
magnets and they experience side effects that concern them, they
should stop using the magnets and contact their health care
providers.
· Consumers who are
considering magnets, whether for pain or other conditions, can
consult the free publications prepared by Federal Government
agencies. See "For More Information."
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If You
Buy a Magnet…
NIKKEN
· Check on the
company's reputation with consumer protection agencies.
· Watch for high
return fees. If you see them before purchase, ask that they
be dropped and obtain written confirmation that they will
be.
· Pay by credit
card if possible. This offers you more protection if there
is a problem.
· If you buy from
sources (such as Web sites) that are not based in the United
States, U.S. law can do little to protect you if you have a
problem related to the purchase.
Sources: The FDA and
the Pennsylvania Medical Society |
12. Is the National Center
for Complementary and Alternative Medicine (NCCAM) funding research on
magnets for pain and other diseases and conditions?
Yes. For example, recent
projects supported by NCCAM include:
· Static magnets, for
fibromyalgia pain and quality of life
· Pulsed electromagnets,
for migraine headache pain
· Static magnets, for
their effects on networks of blood vessels involved in healing
· TMS, for Parkinson's
disease
· Electromagnets, for
their effects on injured nerve and muscle cells
In addition, the papers by
Alfano et al.,26 Swenson,21 and Wolsko et al.27
report on research funded by NCCAM.
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