Despite its great pulling power, the magnet is no medical maestro


Skeptical eye Magnet therapy: Magnet therapy has a history stretching back to Paracelsus, a physician and alchemist who practised in the early part of the 16th century.

He used naturally occurring magnetite or lodestone in the treatment of a variety of ailments. Perhaps the most famous promoter of magnetic therapy, however, was Franz Mesmer who gave his name to mesmerism and worked in the latter half of the 18th century. Initially he practised using magnets and "magnetised" water.

His procedure involved having a patient hold two metal rods that were immersed in magnetised water. He would stand behind the patient and wave magnetic wands above them. He later found that he could obtain equally successful results by just waving his hands above the patient. Eureka! He had discovered animal magnetism which he vigorously promoted from his premises in Paris.

Following complaints from the medical community at the time, Louis XVI appointed a commission to investigate Mesmer's activities. The commission included Benjamin Franklin, well known for his electrical experiments involving flying kites in lightening storms, and Antoine Lavoisier, the famous French chemist.

A number of controlled experiments were set up that demonstrated convincingly that the effects of mesmerism were the result of suggestion. Mesmer consequently retired to Austria and oblivion.

In recent times, magnetic therapies have again being touted as effective in the treatment of a wide range of conditions, including back pain, dental pain, multiple sclerosis, circulatory disease, blood pressure problems, cancer and so on.

As usual, the bulk of the evidence cited in its favour consists of anecdotes and testimonials. There is little in the way of objective research to recommend it - and a wealth of studies and theoretical reasons to seriously doubt its efficacy.

In the US, legal and regulatory action has been taken against a number of individuals and companies to prevent them from making claims that magnet therapy is effective as a medical treatment for a wide range of conditions.

Among the primary promoters of magnets today are athletes who claim they have had positive healing experiences, and pharmacists who join in the legion of retailers who share in the multimillion euro annual spend on these useless devices.

The athletes may be fooled by the well-known fallacy, post hoc ergo propter hoc (after this therefore because of this). Perceived improvements are more likely due to increased localised heat and support provided by the various wraps within which the magnets are strapped to the body, or to the ubiquitous placebo effect.

Pharmacists, as trained scientists, should simply understand enough basic physics to know better. There has been discussion in the pharmacological literature as to the ethics of selling products and devices that are known not to work.

One pharmacist I challenged on the matter stated that he was merely giving customers what they wanted. In my view, this constitutes just another example of lending credibility to nonsense.

Magnets that are sold over the counter as therapeutic devices are so weak as to be useless in penetrating the skin, especially as they are also usually packaged in bandages or pockets that significantly diminish their power.

They are generally no stronger than refrigerator magnets and their effect falls off rapidly with distance. You can easily demonstrate this for yourself using a fridge magnet and a paper clip.

You might also experiment to see how many sheets of paper must be placed between the magnet and clip to significantly diminish its effect. Ten sheets are equivalent to about 1mm. Consider how a magnet of this strength could possibly penetrate to blood vessels, bones and joints.

Purveyors of magnet therapy often claim that the magnets attract blood to the surface of the skin because of the iron contained in haemoglobin, or that the magnets affect nerve conduction by acting on charged ions. There is no evidence for such mechanisms of operation.

As Michael Shermer, director of the American Skeptics Association, has pointed out, iron atoms in a magnet are crammed together in a solid state about one atom apart from one another. In blood, only four iron atoms are allocated to each haemoglobin molecule and they are separated by distances too great to form a magnet.

This can be easily tested by pricking your finger and placing a drop of blood next to a magnet.

For an interesting discussion that includes accessible explanations of the relevant physics, see an article by David Ramey published in the Scientific Review of Alternative Medicine in spring 1998.

Just as I am about to draw this column to a close, a medical colleague has alerted me to the website of a company marketing a device for €80 that it claims will magnetise your drinking water!

It presents the claim that magnetised water inhibits the development of micro-organisms - viral, fungal and bacterial - and that it acts like an antibiotic without the problems associated with antibiotics. Of course, no objective evidence is produced to support this dubious claim.

It also says that pure water is a mixture of 18 different molecular compounds and 15 different ions. I understood that it was simply H2O. It claims that water energised by the advertised device is transformed into the most healthy drink you can take.

It is distressing to see the continued abuse of scientific terminology in the promotion of questionable devices such as those alluded to above. Where are the modern-day Franklins and Lavoisiers?

• Paul O'Donoghue is a clinical psychologist and founder-member of the Irish Skeptics Society (