Magnesium glycinate is a popular choice, and figuring out the best time to take magnesium glycinate may make a difference in its benefits. What is magnesium glycinate? Because of its excellent absorption, magnesium glycinate is a favorite for people who need to raise their magnesium levels but worry about stomach upset. “If you feel sleepy after daytime supplementation,” Tieu says, “it may be best to take it at night.”Should you take magnesium glycinate with food? Potential side effectsThe main thing to watch out for when supplementing magnesium glycinate is simply overdoing it.