Magnesium

Short summary: Magnesium is an essential mineral involved in hundreds of biochemical reactions; supplementation can correct deficiency and may help specific conditions such as muscle cramps, some types of insomnia, and modestly lower blood pressure in certain populations (see references below).

Key evidence-based points

• Magnesium is an essential electrolyte required for enzymatic reactions, nerve and muscle function, and energy metabolism. (See review) [1]
• Magnesium deficiency (hypomagnesemia) can cause neuromuscular hyperexcitability and muscle cramps; correcting deficiency may relieve cramps when deficiency is present. [2]
• Some randomized trials and systematic reviews report modest improvements in subjective sleep quality with magnesium supplementation, but results are heterogeneous and depend on population and formulation. [3] [4]
• Meta-analyses show small but potentially meaningful reductions in systolic blood pressure with oral magnesium supplementation in some groups; effects vary by baseline blood pressure, dose, and study quality. [5] [6]
• Higher dietary and supplemental magnesium intake is associated with lower risk of cardiovascular disease and all-cause mortality in prospective cohort studies, but association does not prove causation. [7]
• Serum (plasma) magnesium concentration is an insensitive marker of whole-body magnesium status; normal serum magnesium does not rule out deficiency. Clinical context and symptoms should guide testing and treatment. [8]
• Different magnesium salts (oxide, citrate, glycinate, threonate, malate, etc.) have different tolerability and physiologic properties; however, claims about precise absorption percentages for each form are not consistently supported by high-quality clinical trials. Choose a formulation (e.g., glycinate for GI tolerance, citrate for laxative effect) based on goals and tolerability. (Note: summary of common clinical guidance; evidence varies)

Practical guidance

• If you have symptoms consistent with deficiency (muscle cramps, unexplained arrhythmia, severe fatigue) or risk factors (diuretic use, malabsorption, alcoholism), discuss testing and supplementation with a clinician. [1]
• Typical oral supplemental doses in trials range from ~200–500 mg elemental magnesium daily; dosing and form depend on the formulation and individual tolerability. Higher doses increase the risk of diarrhea. [5]
• Magnesium may interact with some medications (e.g., certain antibiotics, bisphosphonates) and should be timed accordingly; consult a clinician or pharmacist. [9]

Products and purchasing

If you prefer to purchase magnesium products at iHerb, search for the desired form (for example, "magnesium glycinate") and append the referral code to the URL so purchases qualify for your Rewards Code. Example search link (EN): iHerb search: magnesium glycinate. For individual product pages, append ?rcode=CIV758 or &rcode=CIV758 to the product URL.

References