Magnesium

What It Is

Magnesium is the fourth most abundant mineral in the body and a cofactor for hundreds of enzymes involved in energy production, protein synthesis, muscle and nerve function, blood glucose control, and bone formation. Common dietary sources include leafy greens, nuts, seeds, and legumes. Soil depletion and food processing have reduced dietary magnesium content significantly over decades.

Mechanism of Action

Magnesium regulates calcium channels, modulates NMDA (glutamate) receptors, activates the parasympathetic nervous system, supports mitochondrial ATP production, and inhibits excessive cortisol release. These mechanisms underlie its clinical applications in sleep, anxiety, blood pressure, muscle cramps, and metabolic health.

Human Research Highlights

• Meta-analysis of 11 RCTs found magnesium glycinate and oxide significantly reduce migraine frequency.
• Multiple RCTs show improvement in sleep quality, including reduced sleep onset time with glycinate formulations.
• A 2016 systematic review found significant reductions in systolic and diastolic blood pressure in hypertensive adults.
• Meta-analyses show modest improvement in fasting glucose and insulin sensitivity.
• Evidence for anxiety reduction in several small RCTs, particularly in deficient individuals.
• Consistent evidence for reducing leg cramps in pregnant women.
• Magnesium supplementation reduces constipation (especially magnesium citrate and oxide forms).

Preclinical & Laboratory Research

• Animal studies confirm role in neurological protection and anxiety reduction.
• Preclinical research on magnesium's role in mitochondrial function and aging.

Research Gaps

• Head-to-head comparisons of different forms for specific indications needed.
• Optimal dosing for each indication not clearly established.
• Long-term cardiovascular outcome data from supplementation trials limited.
• Brain-penetrating threonate form needs more human trial data.

Clinical Relevance

Magnesium is one of the most clinically applicable supplements given how common suboptimal intake is and how many conditions benefit from correction. Form selection matters: glycinate for sleep and anxiety, citrate for constipation, malate for muscle pain, threonate for cognitive support. Testing serum magnesium has limited utility (RBC magnesium is more informative for intracellular status).