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Magnesium Glycinate Side Effects & Safety

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

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Very well tolerated — glycinate form causes less GI distress than other forms
  • Loose stools or diarrhea at very high doses (less common than with citrate or oxide)
  • Drowsiness (a feature, not a bug, when taken before bed)
  • Low blood pressure at very high doses (rare)
  • Caution in kidney disease — impaired magnesium excretion

Drug & Supplement Interactions

  • Antibiotics (tetracyclines, fluoroquinolones) — magnesium chelates these drugs, reducing absorption; separate by 2-4 hours
  • Bisphosphonates (alendronate) — magnesium reduces absorption; separate by 2 hours
  • Diuretics — loop and thiazide diuretics increase magnesium excretion, may worsen deficiency
  • Blood pressure medications — additive hypotensive effects possible
  • Muscle relaxants — potential additive effects

Maximum Dose

Do not exceed: 800mg elemental magnesium/day from supplements (tolerable upper intake level per NIH is 350mg from supplements, though glycinate is well tolerated above this)

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