Fibromyalgia is characterized by myalgia and a combination of different symptoms including pain, fatigue, insomnia, morning rigidity, depression and a reduction in every-day functioning. Its aetiology is not clear, but it has been suggested that deficiency in certain minerals such as magnesium may play a role both in the physiopathology and in contributing to the symptoms.We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.We identified seven systematic reviews which included 11 primary studies of which one was a randomized trial. Our conclusion is that the use of magnesium and malic acid in patients with fibromyalgia makes little or no difference on pain and on depressive symptoms.