It is recognized that of all the medical equipment in radiology, nuclear magnetism is the safest. This means that people are not afraid of magnetic fields, but more afraid of rays. High magnetic fields do have a negative impact on the human body, but the magnetic content in a magnetic brush is so limited that it is unlikely to have any effect on the human body at all.
The magnetic brush can promote the microcirculation system by contacting the skin meridians, which has a very weak effect on promoting blood circulation, improving the human physiological magnetic field, and eliminating fatigue, which is good for sleeping, but not great.
The bad thing is not clear yet.