Sixty-four patients with painful rheumatoid arthritis of the knee took part in a study of magnetic pads. The patients were randomly assigned to wear either (1) four MagnaBloc(R) 1900 Gauss magnets, or (2) one real magnet and three “sham” magnets, measuring 720 Gauss total. The magnets were tested beforehand to ensure that their magnetic field penetrated 5 cm into tissue. After one week of wearing the magnets, both groups reported a significant reduction in pain. People in the magnet group reported a greater improvement in symptoms, but there was no change in other measures of improvement, such as physician evaluation, range of motion, or inflammatory blood markers. These results do not support the use of magnets in treating an inflammatory disease such as rheumatoid arthritis, and it is possible that any improvements patients experienced were due to placebo effects.
Chronic low back pain
In 2000, the Journal of the American Medical Association published a report of a small clinical trial that did not support the use of magnets for treating chronic low back pain. Twenty people were given both real magnets (around 300 Gauss) and “sham” magnets, but were not told which were which. Half of the people wore the real magnets for two weeks, took a week off, then switched to the sham magnets, and the other half did the opposite. At the end of the study, people reported having less pain both while wearing the real magnets and while wearing the sham magnets. This indicates that the reduction in pain was due to a placebo effect. However, unlike other studies in which magnets were worn all day, in this study people used them only for six hours a day, Monday, Wednesday, and Friday.
The use of magnetized mattress pads by women with fibromyalgia was studied in a small clinical trial. For 16 weeks, 13 women used unipolar magnetized mattress pads (about 1100 Gauss) and 12 used non-magnetized mattress pads. The women sleeping on magnetized mattress pads reported greatly improved pain, sleep problems, fatigue, and quality of life compared to the women using sham mattress pads. However, the two groups were not totally equal: women who were given sham mattress pads, on average, were heavier (the magnetic field may have not penetrated as deeply) and had higher use of anti-anxiety and pain medications, indicating that they probably had more severe pain to begin with. For these reasons, the results of this study are not very strong.
A clinical trial studied the use of bipolar 300-500 Gauss Bioflex(R) magnets in 50 patients with painful postpolio syndrome. Half of the patients were given real magnets to apply to their most painful body part, while the other half were given “sham” magnets. After 45 minutes, doctors measured the amount of pain in that body part by palpating it and with a questionnaire. People using the real magnets reported a greater reduction in pain, but there are a few problems with these findings. There were more people with muscle pain, compared to arthritis pain, in the group that used real magnets. This is important because the nature of these two types of pain may be different. Also, because many different sized magnets were used to treat many different body parts, this study lacks consistency.
Thirty-four otherwise healthy patients with inner heel pain enrolled in a study of magnetized insoles. Half of the patients were given magnetized insoles, while the other half used regular, non-magnetized insoles. After four weeks of constantly using the insoles, about 60% of both groups reported improvements in heel pain. This indicates that the improvements may have been due to the insoles, not the magnets.