Magnesium (glycinate/citrate)
Magnesium is a cofactor for more than 300 enzymatic reactions: ATP metabolism, DNA repair enzymes, insulin-signaling pathways, plus it keeps your vascular tone in check and your heart's electrical rhythm stable. Keep your status where it should be and you're backing normal blood pressure, glucose handling, and neuromuscular function, all at once.
Evidence
Observational cohorts link higher magnesium intake and status to lower cardiovascular and all-cause mortality, which sounds impressive until you remember observational data can't prove cause. RCTs and meta-analyses back up modest reductions in blood pressure and real improvements in insulin sensitivity and fasting glucose, especially if you're deficient or dealing with diabetes or prediabetes. What's missing: longevity RCTs. Nobody's run the trial that proves magnesium extends your life. That's why the grade lands as mixed, mostly riding on correcting a deficiency rather than some independent effect on how long you live.
Interactions
Reduces absorption of oral bisphosphonates, tetracycline/fluoroquinolone antibiotics, and levothyroxine (separate by 2-4 hours); potassium-sparing diuretics and reduced kidney function raise retention risk. Generally no direct anticoagulant interaction.
Cautions
Excess supplemental magnesium causes diarrhea; serious hypermagnesemia risk in chronic kidney disease and with certain medications. The supplemental UL is 350 mg/day of elemental magnesium (food magnesium is not capped). Use caution with impaired renal function.
Food sources
Leafy greens (spinach, chard), pumpkin and chia seeds, almonds, cashews, legumes, whole grains, and dark chocolate.
