NutriStack
Liothyronine and Vitamin B7, a caution.
Vitamin B7, also called biotin, does not directly change liothyronine levels, but it can distort thyroid lab tests used to monitor therapy. Many immunoassays can show falsely low TSH and falsely high T3 or T4 after high-dose biotin. This can make liothyronine dosing look excessive or make hyperthyroidism appear worse than it is.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Liothyronine and Vitamin B7
- Pair type
- Caution
- Evidence (highest tier)
- Strong
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Strong evidence
Caution
What is happening. Vitamin B7, also called biotin, does not directly change liothyronine levels, but it can distort thyroid lab tests used to monitor therapy. Many immunoassays can show falsely low TSH and falsely high T3 or T4 after high-dose biotin. This can make liothyronine dosing look excessive or make hyperthyroidism appear worse than it is.
Mechanism. Excess biotin competes with assay biotin-streptavidin binding. In sandwich assays it can cause falsely low results, while in competitive thyroid hormone assays it can cause falsely high free or total thyroid hormone results.
Recommendation. Stop biotin for at least 48 to 72 hours before thyroid labs, and longer for high-dose products if your clinician or lab recommends it. Tell the lab and prescriber about any hair, skin, nail, or B-complex product that contains biotin.
Sources (3)
- Ylli D, Soldin SJ, Stolze B, Wei B, Nigussie G, Nguyen H, Mendu DR, Mete M, Wu D, Gomes-Lima CJ, Klubo-Gwiezdzinska J, Burman KD, Wartofsky L. Biotin Interference in Assays for Thyroid Hormones, Thyrotropin and Thyroglobulin. Thyroid. 2021;31(8):1160-1170. PMID 34042535
- Piketty ML, Prie D, Sedel F, Bernard D, Hercend C, Chanson P, Souberbielle JC. High-dose biotin therapy leading to false biochemical endocrine profiles: validation of a simple method to overcome biotin interference. Clin Chem Lab Med. 2017;55(6):817-825. PMID 28222020
- Odhaib SA, Mansour AA, Haddad NS. How Biotin Induces Misleading Results in Thyroid Bioassays: Case Series. Cureus. 2019;11(5):e4727. PMID 31363424
Stack Score
How this pair moves the number.
Effect on the composite score
If both Liothyronine and Vitamin B7 are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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