Can you take Levothyroxine and Magnesium Oxide together?
Yes, with care — this combination needs a precaution.
Levothyroxine and Magnesium Oxide 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.
Divalent cations chelate levothyroxine in the gut and reduce absorption by up to 30%.
Inferred from a shared mechanism, not documented for this specific pair. The same explanation is applied to other combinations that work the same way.
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.
Take levothyroxine on empty stomach; separate mineral supplements by at least 4 hours.
TimingSources for timing: Jumps to this entry in the sources and references list at the end of the page.
Separate Levothyroxine and Magnesium Oxide 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: Levothyroxine + Magnesium Oxide(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed label: Levothyroxine(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- DailyMed label: Magnesium Oxide(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
- Ashwagandha and LevothyroxineNote
- Calcium and LevothyroxineCaution
- Esomeprazole and LevothyroxineCaution
- Iron (ferrous bisglycinate) and LevothyroxineCaution
- Lansoprazole and LevothyroxineCaution
- Levothyroxine and Magnesium CitrateCaution
- Levothyroxine and Magnesium GlycinateCaution
- Levothyroxine and OmeprazoleCaution
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.