Can magnesium help with anxiety, stress or low mood?

Possibly, but the evidence is poor. A 2017 review of 18 studies found that magnesium might ease anxiety in people prone to it, such as people with mild anxiety or premenstrual syndrome. The authors rated the quality of the evidence as poor.^[1] Magnesium had no effect on anxiety after childbirth, and no study used a validated measure of stress.^[1]

For low mood, a 2020 review found mixed results.^[2] In one trial, 126 adults with mild to moderate depression took 248 mg of magnesium a day as magnesium chloride for 6 weeks. Their depression score fell by 6.0 points more than in the weeks without magnesium, and their anxiety score by 4.5 points.^[3] The trial had no placebo, so people knew when they were taking magnesium.^[3]

People who take antidepressants or another medicine every day should ask a doctor or pharmacist first.^[4]