A manufactured magnesium salt designed to move more magnesium into the brain. Short, mostly industry-funded human trials report gains in thinking speed, memory and self-rated sleep; independent replication is thin and blood magnesium rises only slightly. Loose stools are the usual limit; build-up matters almost entirely with reduced kidney function. The evidence is suggestive rather than settled. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum magnesium | 2.0–2.4 mg/dL | Detects frank deficiency and accumulation |
| Red-blood-cell magnesium | 5.0–6.5 mg/dL | Better proxy for tissue magnesium than serum |
| Estimated glomerular filtration rate | Above 60 mL/min/1.73 m² | Accumulation risk that defines the contraindication |
| Serum creatinine | 0.6–1.0 mg/dL (women), 0.8–1.2 mg/dL (men) | Underlying input to the filtration estimate |
| Serum potassium | 4.0–4.5 mmol/L | Magnesium depletion drives potassium loss |
| Serum calcium (albumin-corrected) | 9.2–10.0 mg/dL | Low magnesium impairs parathyroid hormone release |
| 25-hydroxyvitamin D | 40–60 ng/mL | Activating vitamin D consumes magnesium |
| 24-hour urinary oxalate (stone formers only) | Below 40 mg/24h | Quantifies residual oxalate load in stone formers |
Cadence: Baseline before starting; four-week retesting is uninformative for most people. Practitioner protocols typically retest at three months, then every six to twelve months — more often for kidney markers where filtration is reduced, potassium-sparing diuretics are used, or intake exceeds the upper level.