Scarlett Johansson swears by magnesium. But can supplements really help with digestion, muscle pain, anxiety and sleep?

There are not enough consistent, strong findings to show strong cause and effect between magnesium supplementation and better sleep, dietitians say. Illustration: Guardian Design/Guardian Design/Getty Images

Danielle Shine says her Instagram inbox was filled with questions after Scarlett Johansson was quoted in the Daily Mail and other publications recently saying she takes magnesium to improve her digestion and sleep.

“I know that everybody is taking magnesium now. It’s so helpful,” the actor reportedly told beauty publication Byrdie.