Magnesium may reduce thyroid med absorption
Magnesium can form complexes with levothyroxine, though effect is less pronounced than calcium or iron. Still recommended to separate doses.
Take thyroid medication at least 4 hours before magnesium.
Separate by 4 hours minimum
Magnesium may reduce thyroid med absorption. Take thyroid medication at least 4 hours before magnesium.
Separate by 4 hours minimum
This interaction is rated “Caution” by Formulate. Magnesium can form complexes with levothyroxine, though effect is less pronounced than calcium or iron. Still recommended to separate doses.
Studies from our registry that mention magnesium or thyroid medication. Each links to the primary source and the other Formulate pages citing it.
Mentions thyroid medication · 2026
Memorial Sloan Kettering Integrative Medicine Monograph: Ashwagandha
Primary literature · Monograph
Documents thyrotoxicosis case reports associated with ashwagandha use. States ashwagandha may increase thyroxine levels. Also notes CYP3A4 induction (moderate) and sedative-additive effects. Does not give a hard avoid-with-levothyroxine warning but flags thyroid monitoring.
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 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
Ashwagandha can raise thyroid hormone levels and stack additively with levothyroxine, risking thyrotoxicosis.
Calcium blocks thyroid medication absorption
Iron reduces levothyroxine absorption
Iodine supplementation can destabilize thyroid
PPIs can cause hypomagnesemia
High calcium can impair magnesium absorption
Magnesium may enhance BP lowering effect
PPIs impair magnesium absorption
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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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