NutriStack
Levothyroxine and Magnesium Malate, timing-sensitive.
Magnesium malate may reduce levothyroxine absorption if taken at the same time. Direct studies with this exact magnesium salt are lacking, but the clinical concern is the magnesium cation, not the malate portion. Repeated co-administration can make thyroid replacement appear too weak.
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At a glance
- Substances
- Levothyroxine and Magnesium Malate
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Timing Sensitive · Emerging evidence
Timing Sensitive
What is happening. Magnesium malate may reduce levothyroxine absorption if taken at the same time. Direct studies with this exact magnesium salt are lacking, but the clinical concern is the magnesium cation, not the malate portion. Repeated co-administration can make thyroid replacement appear too weak.
Mechanism. Magnesium can form poorly absorbed complexes with levothyroxine or reduce dissolution in the gut. This lowers the amount of active hormone reaching systemic circulation.
Recommendation. Take levothyroxine first with water, then wait at least 4 hours before magnesium malate. If thyroid symptoms or TSH change after adding magnesium, review timing before changing the levothyroxine dose.
Minimum separation. 240
Sources (2)
- Liwanpo L, Hershman JM. Conditions and drugs interfering with thyroxine absorption. Best Pract Res Clin Endocrinol Metab. 2009;23(6):781-792. PMID 19942153
- Skelin M, Lucijanic T, Amidzic Klaric D, Resic A, Bakula M, Liberati-Cizmek AM, Gharib H, Rahelic D. Factors Affecting Gastrointestinal Absorption of Levothyroxine: A Review. Clin Ther. 2017;39(2):378-403. PMID 28153426
Stack Score
How this pair moves the number.
Effect on the composite score
If both Levothyroxine and Magnesium Malate are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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