The treatment involves placing magnets on or near the body, with the goal of speeding up healing and reducing pain. Supporters of 'magnet therapy' believe so and have proposed several explanations for how magnets might work. Although these explanations sound reasonable, there have been no scientific studies showing that magnets actually have such effects on the body. There are two main kinds of permanent magnets, referred to as unipolar and bipolar. Bipolar magnets are arranged so that alternating magnets have opposite poles in contact with the body.
Magnets also come in different shapes.
There have been only a few medical research studies, and the results are conflicting. Those who got the active treatment had more pain relief than those who got the placebo treatment. These studies support the idea that magnets may help relieve certain kinds of pain. On the other hand, in a recent study of people with low back pain, bipolar magnets were no more effective than placebo. There are other possible explanations for your friends' pain relief.