Magnesium glycinate, citrate and L-threonate aren't interchangeable. Here's how the three forms differ, what the research actually says, and how to decide which magnesium makes sense for you.

Magnesium is everywhere right now — for sleep, stress, muscle cramps and more. But do you actually need a supplement? Here’s how to think about magnesium intake, testing, different forms, dosage and what you’re actually trying to accomplish.