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Types of Magnesium Glycinate: Forms & Bioavailability

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Forms Comparison

FormBioavailabilityBest For
Magnesium Glycinate (Bisglycinate)High (superior absorption)Sleep and anxiety — best-tolerated form with dual magnesium + glycine benefits
Magnesium L-ThreonateHigh (crosses BBB)Cognitive support — specifically designed to increase brain magnesium levels (Magtein)
Magnesium CitrateModerate-HighGeneral supplementation — well absorbed but may cause loose stools at higher doses
Magnesium OxideLow (4-5%)Budget option — poorly absorbed but high elemental magnesium content per capsule

Magnesium Glycinate (Bisglycinate)

Bioavailability: High (superior absorption). Best for: Sleep and anxiety — best-tolerated form with dual magnesium + glycine benefits.

Magnesium L-Threonate

Bioavailability: High (crosses BBB). Best for: Cognitive support — specifically designed to increase brain magnesium levels (Magtein).

Magnesium Citrate

Bioavailability: Moderate-High. Best for: General supplementation — well absorbed but may cause loose stools at higher doses.

Magnesium Oxide

Bioavailability: Low (4-5%). Best for: Budget option — poorly absorbed but high elemental magnesium content per capsule.

Full Magnesium Glycinate Guide

References

  1. RCTAbbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B (2012). The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences. PubMed
  2. ReviewBoyle NB, Lawton C, Dye L (2017). The effects of magnesium supplementation on subjective anxiety and stress — a systematic review. Nutrients. DOI PubMed
  3. RCTHeld K, Antonijevic IA, Künzel H, et al. (2002). Oral Mg(2+) supplementation reverses age-related neuroendocrine and sleep EEG changes in humans. Pharmacopsychiatry. DOI PubMed
  4. Inagawa K, Hiraoka T, Kohda T, Yamadera W, Takahashi M (2006). Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms. DOI
  5. RCTDall RD, Cheung MM, Shewokis PA, Altasan A, et al. (2023). Combined vitamin D and magnesium supplementation does not influence markers of bone turnover or glycemic control: A randomized controlled clinical trial.. Nutrition research (New York, N.Y.). DOI PubMed
  6. RCTCheung MM, Dall RD, Shewokis PA, Altasan A, et al. (2022). The effect of combined magnesium and vitamin D supplementation on vitamin D status, systemic inflammation, and blood pressure: A randomized double-blinded controlled trial.. Nutrition (Burbank, Los Angeles County, Calif.). DOI PubMed