A critical review of randomized controlled trials of static magnets for pain relief.

OBJECTIVE The aim of this review was to establish whether there is evidence for or against the efficacy of static magnets to produce analgesia. METHODS A systematic literature review was undertaken of studies that compared the use of static magnets with an appropriate control for the treatment of pain. Study methods, their quality, and outcome were also reviewed. RESULTS Overall, 13 of the 21 studies reported a significant analgesic effect due to static magnets. Of the 18 better quality studies with 3 points or more on the quality assessment, 11 were positive and six were negative, and in one there was a non-significant trend towards a positive analgesic effect. In two of the negative studies, there are concerns over adequacy of magnet power for the type of pain, and in the other study of duration of exposure to the magnetic field. If these two studies are excluded on the grounds of inadequate treatment, then 11 out of 15 (73.3%) of the better quality studies demonstrated a positive effect of static magnets in achieving analgesia across a broad range of different types of pain (neuropathic, inflammatory, musculoskeletal, fibromyalgic, rheumatic, and postsurgical). CONCLUSIONS The weight of evidence from published, well-conducted controlled trials suggests that static magnetic fields are able to induce analgesia.