Magnesium × Levothyroxine Interaction

Mechanism

Magnesium may reduce levothyroxine absorption, similar to calcium.

Effect

Reduced levothyroxine absorption; hypothyroid symptoms

Management

Separate doses by at least 4 hours.

Plain Language Summary

✨ AI-generated · Qwen 3.6 · grounded in 2 sources · methodology

This combination requires caution because magnesium can prevent your body from absorbing levothyroxine properly. This may lead to symptoms of an underactive thyroid if the doses are taken too close together.

Source

Singh N et al. JAMA 2000 (extrapolated from calcium data)

Research

Supporting Research

The association between circulating magnesium and clinically relevant outcomes in patients with chronic kidney disease: A systematic review and meta-analysis

PMID:33419615 DOI 2021

Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery

PMID:23440790 DOI 2013

Association between Serum Magnesium and Fractures: A Systematic Review and Meta-Analysis of Observational Studies

PMID:36986033 DOI 2023

A meta-analysis of methane-mitigation potential of feed additives evaluated in vitro

PMID:38353472 DOI 2024

Dietary Approaches to Stop Hypertension (DASH) for the primary and secondary prevention of cardiovascular diseases

PMID:40326569 DOI 2025

Circulating and dietary magnesium and risk of cardiovascular disease: a systematic review and meta-analysis of prospective studies

PMID:23719551 DOI 2013

Inhaled magnesium sulfate in the treatment of acute asthma

PMID:29182799 DOI 2017

Pharmacological interventions for benzodiazepine discontinuation in chronic benzodiazepine users

PMID:29543325 DOI 2018

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Medical Disclaimer: This interaction record is for informational and educational purposes only and does not constitute medical advice. Always consult your healthcare provider or pharmacist before combining any supplement with prescription medications.