Magnesium does not get the attention sodium does, mostly because sodium loss is obvious. You can taste salt on your skin after a hard session. Magnesium deficiency stays quiet, which is exactly why it is worth explaining.
What it does
Magnesium is a cofactor in several hundred enzymatic reactions in your body, including the ones behind muscle relaxation, protein synthesis and nerve function. Calcium triggers a muscle contraction. Magnesium is part of what lets that muscle relax afterward. Run short on it and the two ends of that cycle stop working cleanly, which shows up as cramping, tightness and fatigue that does not track with how hard you trained.
Why athletes run short
Magnesium leaves the body through sweat and urine, both of which climb with training volume. At the same time, a college athlete's diet, eaten on the run between classes and practice, does not always hit the intake levels magnesium requires from leafy greens, nuts and whole grains. Higher losses combined with inconsistent intake explain why magnesium deficiency shows up disproportionately in athletic populations, including ones eating what looks like a reasonable diet on paper.
The form matters as much as the dose
Not all magnesium behaves the same, and this is where labels cut corners. Magnesium oxide is the cheapest form to manufacture, and it lets a brand print a larger milligram number, since oxide is a low percentage of elemental magnesium relative to its weight. It also absorbs poorly and is a known cause of stomach upset, the last thing you want before training.
Magnesium citrate costs more, and the label number looks smaller for the same practical dose, but it absorbs better and sits easier in the stomach. That is the form in NOXE: 150mg of magnesium citrate, chosen for what your body can use rather than what looks best on paper.
What to do with this
Check the form on any electrolyte label, not only the milligram count. Citrate, glycinate and malate absorb better than oxide. It is a small habit that decides whether the mineral you paid for does anything.