Walk down any supplement aisle and you'll see a dozen different types of magnesium. They're not interchangeable, and the form Quiet Nerves uses wasn't picked at random.
Magnesium has to be bonded to something to be stable in capsule form, and that bonding compound affects how well your body actually absorbs it, and how it sits with your stomach. Cheaper forms like magnesium oxide are poorly absorbed and known for causing digestive discomfort.
Magnesium glycinate pairs magnesium with glycine, an amino acid that's gentle on the stomach and helps the mineral get absorbed more efficiently. It's one of the reasons this form shows up so often in formulas built for sensitive users or long-term daily use.
Glycine itself is tied to a calmer nervous system, which is part of why magnesium glycinate often gets credited with supporting both muscle relaxation and a more settled feeling in the evening — on top of magnesium's core role in nerve signaling.