Can You Take Levothyroxine and Vitamin K Together?
No documented interaction was identified between vitamin K and levothyroxine in the sources reviewed.
What the interaction means
Levothyroxine's FDA label's only "vitamin K" hits ("VITAMIN K ANTAGONIST", "VITAMIN K", "VITAMIN K INHIBITORS") are inside its generic pharmacologic-class taxonomy dropdown, not prose interaction statements. MedlinePlus's vitamin K page does not mention levothyroxine.
No documented interaction was identified in the authoritative sources reviewed. This is not a guarantee that no interaction exists for every dose, formulation, or individual -- it means the sources checked did not document one.
Practical context
Both substances' own current authoritative sources were checked directly, full text, in both directions; the taxonomy-list mentions were deliberately not treated as a real interaction claim.
What the sources say
Last reviewed 2026-08-23
Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.
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- Vitamin K and WarfarinUse caution
- Vitamin K and Vitamin DInsufficient evidence
- Vitamin K and CalciumInsufficient evidence
- Vitamin K and IronInsufficient evidence
- Vitamin K and CiprofloxacinInsufficient evidence
- Vitamin K and CreatineInsufficient evidence
- Vitamin K and SpironolactoneInsufficient evidence
- Vitamin K and St. John's WortInsufficient evidence
- Vitamin K and CaffeineInsufficient evidence
- Vitamin K and CopperInsufficient evidence
- Vitamin K and Vitamin B12Insufficient evidence
- Vitamin K and PotassiumInsufficient evidence
- Vitamin K and TurmericInsufficient evidence
- Vitamin K and ZincInsufficient evidence
- Vitamin K and DoxycyclineInsufficient evidence
- Vitamin K and OmeprazoleInsufficient evidence
- Vitamin K and CoQ10 (Coenzyme Q10)Insufficient evidence
- Vitamin K and MagnesiumInsufficient evidence
- Vitamin K and ProbioticsInsufficient evidence
- Vitamin K and SertralineInsufficient evidence
- Vitamin K and MetforminInsufficient evidence
- Vitamin K and MelatoninInsufficient evidence
- Vitamin K and AtorvastatinInsufficient evidence