Do magnetic wristbands work

That depends on what you expect them to do. I believe they have a placebo effect, but they may also affect your nervous system as can be described through the science of acu-pressure. Much of science remains hypothetical and speculative.

There is the possibility that the magnetic fields serve to protect the nearby tissues from harmful radiation in much the same way as the earth's magnetic fields do so. It could be that this is as beneficial as taking many anti-oxidant supplements. There is also the reality that some things work for some people but not others. I don't think that they are anything miraculous.