NutriStack
Levothyroxine and Zinc Picolinate, timing-sensitive.
Zinc picolinate may interfere with levothyroxine absorption if taken together. The evidence is weaker than for calcium or iron, but levothyroxine is sensitive to intestinal binding by mineral cations. Daily same-time use can create preventable thyroid lab fluctuation.
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At a glance
- Substances
- Levothyroxine and Zinc Picolinate
- 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. Zinc picolinate may interfere with levothyroxine absorption if taken together. The evidence is weaker than for calcium or iron, but levothyroxine is sensitive to intestinal binding by mineral cations. Daily same-time use can create preventable thyroid lab fluctuation.
Mechanism. Zinc ions can plausibly form poorly absorbed complexes with levothyroxine or reduce its free concentration in the gut. Picolinate changes zinc delivery but does not eliminate zinc's cation-binding potential.
Recommendation. Take zinc picolinate at least 4 hours away from levothyroxine. Keep your thyroid dose on a consistent empty-stomach schedule and monitor labs after supplement changes.
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 Zinc Picolinate 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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