Do magnets have statistically significant effects on humans?
Some example claims are in the Wikipedia article on Magnet therapy.
Which says:
Practitioners claim that subjecting certain parts of the body to magnetostatic fields produced by permanent magnets has beneficial health effects. These claims are both physically and biologically implausible and no effects on health or healing have been established.
While there are studies that have shown some relief of pain, most do not show those results. Given the other factors that could cause false-positives, it seems unlikely that the magnets are the cause.
What the Science Says About Magnets for Pain
Scientific evidence does not support the use of magnets for pain relief.
Preliminary studies looking at different types of pain—such as knee, hip, wrist, foot, back, and pelvic pain—have had mixed results. Some of these studies, including a 2007 clinical trial sponsored by the National Institutes of Health that looked at back pain in a small group of people, have suggested a benefit from using magnets. However, many studies have not been of high quality; they included a small number of participants, were too short, and/or were inadequately controlled. The majority of rigorous trials, however, have found no effect on pain.
Transcranial Magnetic Stimulation gets used in neuroscience to affect the brain. Klein et al showed in a placebo controlled double blind study that it can be used to treat recurrent major depression.
Abstract
Converging evidence points to hypofunction of the left prefrontal cortex in depression. Repetitive transcranial magnetic stimulation (rTMS) activates neurons near the surface of the brain. We questioned whether daily left prefrontal rTMS might improve mood in depressed subjects and report a pilot study of such treatment in six highly medication-resistant depressed inpatients. Depression scores significantly improved for the group as a whole.
—Daily repetitive transcranial magnetic stimulation (rTMS) improves mood in depression by George, Mark S.; Wassermann, Eric M.; Williams, Wendol A.; Callahan, Ann; Ketter, Terence A.; Basser, Peter; Hallett, Mark; Post, Robert M.
Magnets can be used to unobtrusively remove small metal parts from human body remained after suffering an injury caused by a near bomb explosion. There's a so called 'magnet trap' developed by Dr. Dusanka Mandic
MIT neuroscientists published a study which provides evidence that a magnetic field applied to certain portions of the brain can impact morality judgements. If true, that seems to be a clear example of a magnet's noticeable effect on humans.
When we judge an action as morally right or wrong, we rely on our capacity to infer the actor’s mental states (e.g., beliefs, intentions). Here, we test the hypothesis that the right temporoparietal junction (RTPJ), an area involved in mental state reasoning, is necessary for making moral judgments. In two experiments, we used transcranial magnetic stimulation (TMS) to disrupt neural activity in the RTPJ transiently before moral judgment (experiment 1, offline stimulation) and during moral judgment (experiment 2, online stimulation).
In both experiments, TMS to the RTPJ led participants to rely less on the actor’s mental states. A particularly striking effect occurred for attempted harms (e.g., actors who intended but failed to do harm): Relative to TMS to a control site, TMS to the RTPJ caused participants to judge attempted harms as less morally forbidden and more morally permissible. Thus, interfering with activity in the RTPJ disrupts the capacity to use mental states in moral judgment, especially in the case of attempted harms.
—Disruption of the right temporoparietal junction with transcranial magnetic stimulation reduces the role of beliefs in moral judgments by Liane Young, Joan Albert Camprodon, Marc Hauser, Alvaro Pascual-Leone, and Rebecca Saxe
