Magnesium Trumps Glycine for Deep Sleep, with Glycine Aiding Sleep Onset

Two board-certified doctors compare glycine and magnesium for deep sleep. They say magnesium has stronger evidence for increasing deep sleep time, especially in people with magnesium deficiency, while glycine may improve sleep onset and overall sleep quality though objective deep-sleep benefits are less clear. For best results, both may be taken about 60 minutes before bed (magnesium with food to ease digestion), but dosing should be tailored with a clinician. The takeaway: magnesium is more reliably linked to deeper sleep, while glycine can help you fall asleep faster and wake feeling less groggy.