The magnetic sensing seems to be active only when the light is of the right color. However, despite much searching, good experiments on wound healing show no effect of magnetic fields. The physics of the situation is such that the much weaker fields, used in healing magnets, will have negligible effect on cells. As every silver lining has its cloud, so magnets themselves can cause pathological conditions. Perhaps the greatest danger posed by self-treatment with magnets is the chance that this might preclude a person with a serious medical problem from seeking professional medical help.
Magnets can be therapeutic, for permanent magnets have already been shown to be beneficial.
The cattle are fed a pill-shaped magnet, which then stays in a stomach, traps the metal, preventing problems. In a well-designed, quantitative study, magnets were used simply to pull the lower jawbone forward mechanically. Magnets are marketed to make people even more attractive, by improving the appearance of faces which wear a mask containing magnets. There is a paucity of face-saving supporting data. It is difficult enough to establish the efficacy of a pharmaceutical drug in clinical trials, and magnet therapy deserves to be tested with the same rigor.