Silicone wrist bands and other “performance jewellery” have become commonplace among sports stars (see Paul Collingwood and Andrew Strauss, England cricketers, who are bedecked in several varieties). Power Balance, Harmony, Ionic, Q-Ray, Balance, Bio-Ray, IRenew and Rayma are some of the many brands that you might see online or in sports stores. I have been writing about negative ions and balance bands for a few years now, but most of that focused on the inherent lack of a plausible mechanism by which the things could work. Since I wrote those posts, there have been a number of clinical trials published, and I thought it would be worth trying to pull some of those together to provide an overview of the science. I have linked to all the studies so you can check them out yourself.
Summary: I found seven studies: four journal articles, one MSc thesis, one research poster, and one conference presentation which was an expansion of a journal article. The studies included a total of 193 participants and looked mainly at balance, strength and agility, all using the Power Balance band (in which holograms are the supposedly active part). None showed any improvement in performance with the band, but study quality varied. Interestingly, some studies suggest that the placebo effect might not even be present. However, another study showed that the placebo effect with this product is strongly dependent upon prior beliefs, and that performance may even suffer while wearing a band if the participant does not believe that the band will help. I was not able to find any tests of bands in which “ions” were purported to be the mode of action.