Can you take Calcium and Levothyroxine together?
Yes, with care — this combination needs a precaution.
Calcium and Levothyroxine can be taken together, but the combination needs a precaution.
Why these two interactSources for why these two interact: Jumps to this entry in the sources and references list at the end of the page.
Calcium reduces absorption of thyroid medication when taken together.
What to do about itSources for what to do about it: Jumps to this entry in the sources and references list at the end of the page.
Separate by about 4 hours.
TimingSources for timing: Jumps to this entry in the sources and references list at the end of the page.
Separate Calcium and Levothyroxine by at least 4 hours. Taking them in the same window is what causes the issue, not taking them on the same day.
The two items in this pair
Levothyroxine
- Category:
- medication
- Typical timing:
- morning
- With food:
- empty_stomach
- Half-life:
- 168 h
Check your whole routine, not just this pair
One pair rarely tells the whole story. DoseRoutine checks every combination in your stack at once — supplements, TRT, peptides, GLP-1s and prescriptions — and schedules the doses so timing conflicts like this one are handled automatically.
Frequently asked
Sources cited on this page
Specific documents referenced by the numbered markers above.
- Levothyroxine interactions with food and dietary supplements — a systematic review(opens in a new tab)PubMed — National Library of Medicine · pubmed.ncbi.nlm.nih.gov/33801406/
- Factors affecting gastrointestinal absorption of levothyroxine: a review(opens in a new tab)PubMed — National Library of Medicine · pubmed.ncbi.nlm.nih.gov/28153426/
- Synthroid (levothyroxine sodium) — FDA prescribing information(opens in a new tab)DailyMed — U.S. National Library of Medicine · dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
Verify at
This assessment is mechanism-based. These publisher search links let you check it against the current evidence — they are not citations, so they are not numbered.
- PubMed: Calcium + Levothyroxine(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed label: Calcium(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- DailyMed label: Levothyroxine(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
Related combinations
Educational information only, not medical advice. DoseRoutine does not diagnose or treat. Talk to your prescriber before starting, stopping or combining anything — especially if you take prescription medication or are pregnant or breastfeeding.