Magnesium has quietly become one of the most sought-after supplements in modern wellness culture, promising better sleep, steadier moods, and faster recovery — and for many, it delivers. Yet the same mineral that calms the nervous system can, in excess, overwhelm it, reminding us that even beneficial things carry thresholds. Experts place the safe ceiling at 400 milligrams daily in supplement form, a limit easier to breach than most people realize when magnesium hides across multiple products. The ancient wisdom holds: the dose makes the poison.