Drug & supplement interaction

Blood Type Diet + Levothyroxine

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

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Blood Type Diet and Levothyroxine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Blood Type Diet and Levothyroxine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Levothyroxine and Blood Type Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Blood Type Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Blood Type Diet at all — not against Levothyroxine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

Blood Type Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Blood Type Diet safety at a glance

Blood Type Diet overall Use caution The diet itself is generally food-based, but restricting whole food groups may lead to nutrient gaps.
Pregnancy Use caution Restrictive eating plans may limit needed nutrients during pregnancy; check with your doctor first.
Breastfeeding Use caution Avoid overly restrictive versions while nursing and ensure adequate calories and nutrients.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine and Blood Type Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Levothyroxine’s Own FDA Label Lists

This is not an interaction — none of it involves Blood Type Diet. These are the most notable effects listed in the ADVERSE REACTIONS section of Levothyroxine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you follow Blood Type Diet and take the medicine. 10 of them are worth acting on rather than waiting out — marked below.

  • A change in thyroid levels Worth acting on
  • Bone thinning Worth acting on
  • Muscle weakness Worth acting on
  • A heart attack Worth acting on
  • Heart failure Worth acting on
  • Wheezing Worth acting on
  • Seizures Worth acting on
  • Chest pain Worth acting on
  • Shortness of breath Worth acting on
  • A severe allergic reaction Worth acting on

Showing the 10 most notable of 32 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed › Blood Type Diet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Blood Type Diet side to compare — that is a limit of the record, not a statement that Blood Type Diet has no side effects.

From our Q&A

Questions About Blood Type Diet 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 Blood Type Diet 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 Blood Type Diet 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

How much people look this up

Where Blood Type Diet 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 Blood Type Diet
Steady interest

#1,363 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Blood Type Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Blood Type Diet and Levothyroxine records this page draws on were last updated June 22, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Eating pattern

About Blood Type Diet

What is Blood Type Diet?

  • Weight loss
  • General wellness
  • Heart health
  • Digestive health
  • Reducing inflammation

The Blood Type Diet claims that eating foods matched to your ABO blood type improves health and weight, but good-quality studies have not shown that blood type determines who benefits from a given diet. Any health improvements people see are more likely from simply eating more whole, unprocessed foods. Talk to a pharmacist or doctor before making big changes, especially if you have a health condition.

Eating plan (whole-food diet based on ABO blood type)

An interaction check asks whether these two react with each other — it does not ask whether Blood Type Diet is a good idea for someone in your situation. Here is what our Blood Type Diet record says about it on its own.

Blood Type Diet: dosing

There is no "dose" for the Blood Type Diet — it is an eating pattern, not a pill. Followers are given food lists for their blood type and adjust meals accordingly.If you want to try it, focus on the healthy parts (more whole foods, fewer processed foods) and make sure you still get a full range of nutrients. A pharmacist, doctor, or registered dietitian can help you plan a balanced version and decide whether any supplement, such as a multivitamin, is needed.

From our Blood Type Diet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Blood Type Diet 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 & Blood Type Diet

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Blood Type Diet list.

See the full Blood Type Diet interactions page
See every supplement checked against Levothyroxine, ranked by severity
Evidence & sources

Blood Type Diet References

The 1 references that drive our Blood Type Diet monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Barnard ND, Rembert E, Freeman A, Bradshaw M, Holubkov R, Kahleova H. Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention. J Acad Nutr Diet. 2020;S2212-2672(20)31197-7. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Following Blood Type Diet While Taking Levothyroxine: Common Questions

Is it safe to follow Blood Type Diet while taking Levothyroxine?
We do not list a known interaction between Blood Type Diet and Levothyroxine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Levothyroxine interact with any supplements?
Yes. Levothyroxine has documented interactions with 50 supplements in our database — Blood Type Diet is not one of them. The Levothyroxine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Blood Type Diet monograph Uses, safety profile, and every drug interaction in one place Levothyroxine drug information The full plain-English guide to this medication Levothyroxine supplement interactions Every supplement checked against Levothyroxine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and Blood Type Diet?

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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.