Properties and uses of magnesium citrate

Magnesium in the Body

• Magnesium is the fourth most abundant mineral in the body (after calcium, sodium, and potassium).

• Average reserves in a 70 kg adult: ~25 g, with 80% stored in bones and muscles.

• Key roles:

  • Normal muscle and nerve function

  • Regulation of heart rhythm and blood pressure

  • Immune system support

  • Bone and tooth integrity

  • Blood glucose regulation

  • Facilitates calcium absorption

Daily Requirements and Magnesium Deficiency

• Recommended daily intake: 375 mg

• Causes of deficiency:

  • Poor diet (high in processed foods, low in vegetables and nuts)

  • Soil depletion (acid rain, artificial fertilizers) → reduced magnesium in plants

  • Reduced absorption (intestinal disorders, vitamin D deficiency, proton pump inhibitors)

  • Increased losses: diarrhea, laxatives, diuretics, diabetes, alcohol

  • Increased needs: pregnancy, stress, athletic activity

Early signs of deficiency:

• Muscle cramps and tingling in the feet and fingers

• Muscle pain, dizziness, weakness, arrhythmias

Note: Serum magnesium levels don’t always reflect total body status. Practical assessment is based on dietary intake and medical history.

Absorption and Bioavailability of Magnesium

• Main absorption: small intestine, minor in large intestine

• Peak absorption: 2–2.5 hours after intake

• Absorption depends on the chemical form of magnesium:

  • Inorganic insoluble: oxides, carbonates, hydroxides → low absorption (~4%)

  • Inorganic soluble: chlorides, sulfates → better absorption

  • Organic soluble: citrates, lactates, gluconates → high absorption

  • Chelated (organic complexes): bisglycinates, histidine-Mg → best absorption

• Magnesium citrate stands out due to:

  • High solubility in water and stomach acids

  • Better bioavailability than oxide and some chelates

  • Increased absorption, especially with vitamins D and B6

  • Potential role in preventing oxalate kidney stones

Usage:

• Magnesium oxide and hydroxide are often used locally (as laxatives or antacids)

• For systemic effects, a well-absorbed form like citrate is preferred

Functions of Magnesium in the Body

• Maintains electrolyte balance

• Supports normal muscle and nerve function

• Promotes psychological well-being and reduces fatigue

• Supports energy metabolism

• Bones and teeth:

  • 59% of magnesium stored in bones

  • Participates in formation of hydroxyapatite

  • Aids calcium absorption and incorporation

• Supportive in prevention/treatment of: migraines, cardiovascular diseases, blood pressure regulation, blood glucose regulation

• Particularly important for pregnant women and athletes

Conclusion

Magnesium citrate is the most suitable form for supplementation because:

• It has high bioavailability

• Well absorbed from the digestive tract

• Supports multiple physiological functions

• Reduces the risk of laxative-related side effects seen with other forms of magnesium

Key References:

• Schwalfenberg GK, Genuis SJ. The Importance of Magnesium in Clinical Healthcare. Scientifica 2017

• Hermes Sales C. et al., Nutr Hosp 2014

• Lindberg JS et al., J Am Coll Nutr 1990

• Gröber U et al., Nutrients 2015

• Walker AF et al., Magnes Res 2003

• Kappeler D et al., BMC Nutr 2017

• Abraham GE et al., Ann Clin Lab Sci 1981