Magnesium, Anxiety and Depression

Magnesium has an important role in testosterone production however, it also may play an important role in mental health and wellbeing. Observational studies in humans suggest a link between depression and low levels of magnesium. Animal studies suggest this link may be causal.
Correlations between recording dietary intake of magnesium and depression - association remained significant after controlling for a range of factors. Anxiety was more weakly associated, and association failed to reach statistical significance once other factors were controlled for.
Correlation between low magnesium intake and depression in the elderly

Animal study - Magnesium deficiency increased anxiety in mice and causes problems in HPA axis