There is nothing in the human body that can be affected by weak magnets like those in bracelets. If there was then an MRI would cure almost everything, however, an MRI machine is 2,000-15,000 Gauss. Even if the bracelet uses neodymium magnet(s) it wouldn't have the strength of the weakest of MRI machines and the field wouldn't pass much further than the skin.

Magnetic bracelets work as a decorative piece of Jewelry but nothing else.