Observational studies have found that serum magnesium concentrations are not different between people with and without generalized anxiety disorder[1] and that serum magnesium concentrations are not correlated with self-reported levels of anxiety.[2][3] Some observational studies have found an association between a greater dietary magnesium intake and lower odds of anxiety,[4] but other studies do not confirm that finding.[5][6]
Some clinical trials have compared magnesium to magnesium + pyridoxine (vitamin b6) and found a post-trial decrease in self-reported anxiety and/or stress levels in people in the magnesium group.[7][8][9] However, conclusions concerning the direct effect of magnesium cannot be made from studies lacking a control group who did not take magnesium. Fortunately, there are some randomized controlled trials comparing supplementation with magnesium to a placebo. These studies have mixed outcomes that showed a possible, but weak, effect of magnesium on anxiety.[10][11][12][13][14][15] However, the overall quality of the evidence is low, and high-quality randomized controlled trials are needed.[14][15]