Drug & supplement interaction

Dolomite + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Dolomite has a moderate interaction with Levothyroxine. The calcium in dolomite seems to reduce the absorption and effectiveness of levothyroxine.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Dolomite and Levothyroxine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

LEVOTHYROXINE (Synthroid, others)

The calcium in dolomite seems to reduce the absorption and effectiveness of levothyroxine.
Advise patients to take levothyroxine and dolomite at least four hours apart. The calcium in dolomite reduces levothyroxine absorption, probably by forming insoluble complexes. Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism.
Severity Moderate Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the practical issue with these two together. The calcium in dolomite can grab onto your levothyroxine in the gut and form clumps that your body can't absorb well. The result is less thyroid hormone actually getting into you, which can leave your hypothyroidism undertreated. Over time that might mean the symptoms creeping back, things like fatigue, feeling cold, constipation, weight changes, or dry skin.

The good news is this is easy to manage. You don't have to give up either one, just separate them by at least 4 hours so the dolomite isn't sitting in your stomach with your thyroid pill. Many people take levothyroxine first thing in the morning on an empty stomach and save the dolomite for later. Worth mentioning too: dolomite can contain trace heavy metals, so ask your pharmacist whether a cleaner calcium or magnesium product makes more sense for you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Butner LE, Fulco PP, Feldman G, et al. Calcium carbonate-induced hypothyroidism. Ann Intern Med 2000:132:595. PubMed
  2. Schneyer CR. Calcium carbonate and reduction of levothyroxine efficacy. JAMA 1998;279:750. PubMed
  3. Singh N, Singh PN, Hershman JM. Effect of calcium carbonate on the absorption of levothyroxine. JAMA 2000;283:2822-5. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Dolomite Also Interacts With Other Medications

Dolomite has 56 major, 71 moderate known drug interactions in our database — the Levothyroxine one above is one of them. If you take anything else, check it against the full list below.

Major 56 Moderate 71 No known interaction 2,703 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against Dolomite

Covers the 2,830 medications we’ve checked against Dolomite. Pick one to open its full report.

From our Q&A

Questions About Dolomite or Levothyroxine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Dolomite or Levothyroxine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Levothyroxine

This page covers Dolomite only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).

By severity: 2 major · 39 moderate · 9 minor.

From our pharmacist’s overview on the Levothyroxine page

“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine interaction page

One more smart check

Taking Dolomite as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3 real supplement products containing Dolomite, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Dolomite. Your product may carry other ingredients that interact with Levothyroxine too, on top of Dolomite — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Dolomite and Levothyroxine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Dolomite
Steady interest

#802 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Levothyroxine
Top 10

#2 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Dolomite

What is Dolomite?

Dolomite
  • Source of calcium
  • Source of magnesium
  • Bone health support
  • Antacid for heartburn
  • Mineral supplementation

Dolomite is a natural mineral that provides both calcium and magnesium. However, many health authorities advise against using it because dolomite products have been found to contain heavy metals like lead, arsenic, and mercury, and safer, better-tested calcium and magnesium supplements are widely available.

Read the full Dolomite monograph & all interactions
Medication

About Levothyroxine

What Is Levothyroxine Used For?

Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet

Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.

It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

See full Levothyroxine drug information
Keep checking

Other Drugs & Dolomite

Browse every other medication we’ve checked against Dolomite — both the ones with a known interaction and the ones without. Select any drug for the full detail.

56Major
71Moderate
0Minor
2,702No known interaction
56 Major 71 Moderate 2,702 No interaction
Major

56 interactions

Moderate

71 interactions

Showing 60 of 71 moderate interactions — see all 71 on the Dolomite page.

No interaction 2,702 drugs checked — show the list

We also checked Dolomite against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,702 medications checked with no known interaction — see the full Dolomite list.

See the full Dolomite interactions page
See every supplement checked against Levothyroxine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Dolomite monograph › Uses, safety, and every drug interaction in one place Levothyroxine supplement interactions › Every supplement checked against Levothyroxine, ranked by severity Levothyroxine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Dolomite and Levothyroxine Together: Common Questions

Can you take Dolomite with Levothyroxine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Dolomite and Levothyroxine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Levothyroxine and Dolomite?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.