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On
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- What are magnets?
- Is the use of magnets considered conventional medicine or complementary and alternative medicine?
- What is the history of the discovery and use of magnets to treat pain?
- How common is the use of magnets to treat pain?
- What are some examples of theories and beliefs about magnets and pain?
- How are static magnets used in attempts to treat pain?
- How are electromagnets used in attempts to treat pain?
- What is known from the scientific evidence about the effectiveness of magnets in treating pain?
- Are there scientific controversies associated with using magnets for pain?
- Have any side effects or complications occurred from using magnets for pain?
- What should consumers know if they are considering using magnets to treat pain?
- Is the National Center for Complementary and Alternative Medicine (NCCAM) funding research on magnets for pain and other diseases and conditions?
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. Terms are defined in the “Definitions”
section.
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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.
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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.
Examples
of Products Using Magnets |
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.
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2. Is the use of magnets considered conventional medicine
or complementary and alternative medicine?
Conventional medicine and complementary and alternative
medicine (CAM) are defined in the box below.
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.
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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.
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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.
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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.
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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.
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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
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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 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.
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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
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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.
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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…
- 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
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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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For More Information
-
NCCAM Clearinghouse
Toll-free in the U.S.: 1-888-644-6226
International: 301-519-3153
TTY (for deaf or hard-of-hearing callers): 1-866-464-3615
E-mail: info@nccam.nih.gov
Web site: nccam.nih.gov
Address: NCCAM Clearinghouse, P.O. Box 7923, Gaithersburg, MD 20898-7923
Fax: 1-866-464-3616
Fax-on-Demand service: 1-888-644-6226
-
CAM on PubMed
Web site: www.nlm.nih.gov/nccam/camonpubmed.html
CAM on PubMed, a database developed jointly by NCCAM and the National
Library of Medicine, offers citations to (and in most cases, brief
summaries of) articles on CAM in scientifically based, peer-reviewed
journals. CAM on PubMed also links to many publisher Web sites, which
may offer the full text of articles.
- U.S. Food and
Drug Administration (FDA)
Web site: www.fda.gov
Toll-free in the U.S.: 1-888-INFO-FDA (1-888-463-6332)
The FDA is a Federal agency responsible for protecting
the public health by assuring the safety, efficacy, and security of
medicines, biological products, medical devices, foods, cosmetics,
and consumer products that produce radiation.
Center for
Devices and Radiological Health (CDRH)
Web site: www.fda.gov/cdrh
Toll-free: 1-888-463-6332
The CDRH has consumer information on magnets and magnetic devices
and on buying medical devices online.
-
Federal Trade
Commission (FTC)
Web site: www.ftc.gov
Toll-free in the U.S.: 1-888-382-4357
The FTC is a Federal agency that works to maintain a competitive marketplace
for both consumers and businesses. It regulates all advertising, except
prescription drugs and medical devices, ensuring that advertisements
are truthful and not misleading for consumers. Brochures include ”
‘Miracle’ Health Claims: Add a Dose of Skepticism.”
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Definitions
Alloy: A metallic substance consisting of either a mixture of
two or more metals, or a metal that has been mixed with a nonmetal.
Anecdotal evidence: Evidence made up of one or more anecdotes.
In science, an anecdote is a story about a person’s experience, told by
that person.
Chiropractic: An alternative medical system that focuses on the
relationship between bodily structure (primarily that of the spine) and
function, and how that relationship affects the preservation and restoration
of health. Chiropractors use a type of hands-on therapy called manipulation
(or adjustment) as an integral treatment tool.
Clinical trial: A research study in which a treatment or therapy
is tested in people to see whether it is safe and effective. Clinical
trials are a key part of the process in finding out which treatments work,
which do not, and why. Clinical trial results also contribute new knowledge
about diseases and medical conditions.
Diabetic peripheral neuropathy: A nerve disorder caused by diabetes.
This disorder leads to a partial or complete loss of feeling in the feet
and, in some cases, the hands, and pain and weakness in the feet.
Efficacy: In scientific research, a treatment’s efficacy is its
power to obtain a desired effect, such as reducing pain.
ET: Electromagnetic therapy.
Fibromyalgi | 
