Magnesium in Drinking Water: Health Benefits & Recommended Levels

Overview of Magnesium in Drinking Water

• What it is: Magnesium (Mg) is an essential mineral involved in over 300 enzymatic reactions in the body. It's the second major contributor to water hardness after calcium and a key indicator of mineral water quality.
• Why it matters: Up to 30% of the population is magnesium deficient. Drinking water can provide 10–20% of daily needs. Magnesium in water is highly bioavailable—absorbed better than from many foods or supplements.
• Natural sources: Dissolves from dolomite, magnesite, and other magnesium-rich rocks. Volcanic regions and deep aquifers often have elevated magnesium. Seawater intrusion can also increase levels.
• Optimal range (10–30 mg/L): Provides cardiovascular and metabolic benefits without affecting taste. This range is associated with lower rates of heart disease and diabetes in epidemiological studies.
• Too high (>50 mg/L): Can cause a bitter taste. Very high levels (especially with sulfate) may have laxative effects. Rare in natural water but possible in some mineral springs.
• Too low (<5 mg/L): Missed opportunity for easy mineral supplementation. Very soft water lacking magnesium has been linked to higher cardiovascular mortality in some regions.