High calcium can impair magnesium absorption
Very high calcium intake can reduce magnesium absorption. Ideal ratio is approximately 2:1 calcium to magnesium.
Maintain balanced calcium:magnesium ratio. Consider splitting doses.
Can take together in moderate doses, or separate by 2 hours for high doses
High calcium can impair magnesium absorption. Maintain balanced calcium:magnesium ratio. Consider splitting doses.
Can take together in moderate doses, or separate by 2 hours for high doses
This interaction is rated “Caution” by Formulate. Very high calcium intake can reduce magnesium absorption. Ideal ratio is approximately 2:1 calcium to magnesium.
Studies from our registry that mention magnesium or calcium. Each links to the primary source and the other Formulate pages citing it.
Mentions magnesium · 2018
Superiority of magnesium and vitamin B6 over magnesium alone on severe stress in healthy adults with low magnesemia
Pouteau et al. · PLOS ONE
Mg+B6 combination outperformed Mg alone for stress score reduction in adults with low baseline magnesium.
Mentions magnesium · 2018
The role of magnesium in neurological disorders
Kirkland AE, Sarlo GL, Holton KF · Nutrients
Reviews mechanisms and clinical evidence for magnesium's role in migraine prophylaxis, stress, anxiety, and depression — with strongest RCT support for migraine prevention at 400–600mg/day.
Mentions magnesium · 2016
Effects of magnesium supplementation on blood pressure: a meta-analysis of randomized double-blind placebo-controlled trials
Zhang X, Li Y, Del Gobbo LC, et al. · Hypertension
Meta-analysis of 34 trials (n=2,028) found magnesium supplementation at a median dose of 368mg/day for 3 months significantly reduced systolic BP by 2.00 mmHg and diastolic BP by 1.78 mmHg.
Mentions magnesium · 2016
Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults
Liu et al. · Journal of Alzheimer's Disease
Magnesium L-threonate (Magtein) improved cognitive ability in older adults with cognitive concerns over 12 weeks.
Mentions calcium · 2015
Calcium intake and risk of fracture: systematic review
Bolland et al. · BMJ
Systematic review finding little evidence that increasing calcium intake prevents fractures in community-dwelling adults.
Mentions magnesium · 2012
The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial
Abbasi B, Kimiagar M, Sadeghniiat K, et al. · Journal of Research in Medical Sciences
8-week RCT in elderly with insomnia: 500mg/day magnesium significantly improved subjective insomnia score, sleep efficiency, sleep onset latency, and serum melatonin concentration.
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Other interactions to know
Calcium significantly reduces iron absorption
Calcium blocks thyroid medication absorption
PPIs can cause hypomagnesemia
Calcium may reduce zinc absorption
Magnesium may enhance BP lowering effect
PPIs impair magnesium absorption
NSAIDs may reduce magnesium levels
Magnesium may reduce thyroid med absorption
Check your full stack in the free interaction checker.
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Medical disclaimer. This page is for educational purposes only and does not replace advice from a qualified healthcare provider.
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