Other proponents suggest that the magnets cause water molecules in the blood to line up, somehow improving circulation. Park reports that the therapy magnets he examined appear to be basically the same as the flat, flexible refrigerator magnets such as those that come for free from pizza establishments. Although he admits the magnets were a little stronger and a little thicker than the typical refrigerator magnet, he reports that it still failed to hold even 10 sheets of paper on a file cabinet. Ten sheets is just a millimeter thick, which means, according to Park, that the magnetic fields would barely penetrate the skin. Park warns that magnet therapy can pose a risk to people who ignore conventional medical treatment in favor of it.
Magnets generally cost less than a visit to the doctor and they certainly do no harm.
But magnet therapy can be dangerous if it leads people to forego needed medical treatment.