I started taking Magnesium Glycinate about a month ago for extreme sciatica and piriformis pain, my chiropractor suggested taking it since I won't take prescription muscle relaxers. After a couple of days, the pain started to improve and now, a month later, it is almost 100% gone, it is truly a miracle. I take 600mg all together, 2 150mg in the morning (300mg) and 2 150 mg in the evening before bed (300mg) I think it is also helping me to sleep better as well. I have not had any adverse effects from taking that amount.