Magnesium

Magnesium glycinate is more expensive than the regular magnesium citrate but it is more really absorbed by the body and doesn't cause diarrhea in most people. It was a game changer when I switched to that from the cheap stuff. Really helps calm me down, helps with sleep, body aches, restless legs, etc.
I take 400mg every night a few hours before bed. My doctor said I could go higher because your body just excretes what it doesn't need, within reason. She also said most of the population is deficient in magnesium and could benefit from a supplement.