Whenever I take magnesium I take it as Epsom Salt (magnesium sulfate). I don't know how much I take as I usually dump some in my mouth and swallow it with water as the taste is gross. I don't get an upset stomach usually. But what I do get is strong visuals, like when I close my eyes to go to sleep I get a bunch of visuals of weird stuff in my head and I get very tired and my dreams are vivid. So I only take it at night due to the tiredness. When I don't take magnesium I don't have the tiredness and visuals. I read somewhere that magnesium is an NMDA receptor antagonist like DXM and Ketamine and perhaps in high doses they have similar effects? I know when I used these drugs I got strong visuals when I close my eyes. However these drugs were much stronger than magnesium!