According to Wendie Trubow, MD, adding magnesium—especially combination forms— to your routine can be beneficial for mood and PMS, along with sleep, gut function and migraines. “The only downside to getting too much magnesium happens with the magnesium citrate form, which can cause diarrhea if you get too much,” Trubow said. To find your ideal dose, she says to start low and increase every few days until you are below over-treating. “Believe me,” Trubow said, “you’ll know if you’ve taken too much!” Concerned about your magnesium levels? Here are seven signs you’re not getting enough and how to use an Epsom salt bath to get your daily dose of magnesium.