Drug & supplement interaction

Diiodothyronine + Orlistat

Orlistat brand names: Xenical, Alli.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Diiodothyronine and Orlistat 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

Diiodothyronine and Orlistat

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 Orlistat and Diiodothyronine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Diiodothyronine at all — not against Orlistat, 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.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. 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.

Diiodothyronine safety at a glance

Diiodothyronine overall Use caution It is a thyroid-active compound with limited human safety data and possible effects on the heart and thyroid.
Pregnancy Avoid Avoid during pregnancy; thyroid-active compounds can affect mother and baby and safety is unknown.
Breastfeeding Avoid Avoid while breastfeeding due to unknown effects on the infant.

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

Still wondering about combining Orlistat and Diiodothyronine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Orlistat’s Own FDA Label Lists

This is not an interaction — none of it involves Diiodothyronine. These are the most notable effects listed in the ADVERSE REACTIONS section of Orlistat’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 take both. 10 of them are worth acting on rather than waiting out — marked below.

  • Bleeding in the gut Worth acting on
  • Low blood sugar Worth acting on
  • Pancreatitis Worth acting on
  • Wheezing Worth acting on
  • Low mood Worth acting on
  • A severe allergic reaction Worth acting on
  • Hives Worth acting on
  • Liver problems Worth acting on
  • Bleeding or bruising Worth acting on
  • A higher chance of infection Worth acting on

Showing the 10 most notable of 28 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 Orlistat. Read the label on DailyMed › Where a percentage is shown, it is the share of 25,755 voluntary FDA FAERS reports for Orlistat that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Diiodothyronine’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Diiodothyronine side to compare — that is a limit of the record, not a statement that Diiodothyronine has no side effects.

Overlapping uses

What Orlistat Is Prescribed For, and What Diiodothyronine Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Orlistat is a prescription medicine with approved uses on its FDA label. Diiodothyronine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Orlistat is prescribed for: Xenical and prescription-strength orlistat are approved to help obese adults lose weight and keep it off when used with a reduced-calorie diet. They are intended for people with a body mass index (BMI) of 30 or higher, or 27 or higher if other risk factors such as high blood pressure, diabetes, or dyslipidemia (abnormal cholesterol or fat levels in the blood) are present. Alli is the over-the-counter version, approved for weight loss in overweight adults 18 and older when used with a reduced-calorie, low-fat diet and exercise program.

Diiodothyronine has been studied for:

  • Diabetes studied, not established Diiodothyronine has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Diiodothyronine for diabetes

    Although there has been interest in using oral diiodothyronine for diabetes, there is insufficient reliable information about the clinical effects of diiodothyronine for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Orlistat on your own; if you are taking Diiodothyronine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Orlistat

This page covers Diiodothyronine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Orlistat page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Fish Oil (moderate) and Glucomannan (moderate).

By severity: 1 major · 8 moderate · 9 minor.

From our pharmacist’s overview on the Orlistat page

“People who take Orlistat (Xenical, Alli) for weight loss often browse the very supplement aisle where fiber products and fish oil sit, and both show up on this page, so it deserves genuine attention before you mix anything in. Nearly all 18 ingredients on file can change how oral medications absorb from the gut, and the single major-ra…”

Reviewed by 2 · Jul 18, 2026

Open the Orlistat interaction page

One more smart check

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

We hold 58 real supplement products containing Diiodothyronine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Diiodothyronine. Even though Diiodothyronine itself has no known interaction with Orlistat, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Diiodothyronine and Orlistat 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 Diiodothyronine
Steady interest

#1,122 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Orlistat
Top 10%

#242 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. Diiodothyronine is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Diiodothyronine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Diiodothyronine and Orlistat 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 .
Supplement

About Diiodothyronine

What is Diiodothyronine?

  • Weight loss and fat burning
  • Boosting metabolism
  • Bodybuilding and cutting
  • Increasing energy

Diiodothyronine (T2) is a thyroid hormone metabolite sold as a fat-loss and metabolism supplement, mostly in the bodybuilding world. Human evidence for its safety and effectiveness is very limited, and because it can affect the thyroid and heart, it should not be used without medical supervision.

Capsules, tablets, powders (sold as 'T2' supplements)

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

Diiodothyronine: dosing

There is no established, medically recommended dose of T2. It has not been studied well enough in humans to define a safe and effective amount.If a product lists a dose on the label, do not assume it is safe just because it is printed there. If you choose to use it despite the limited evidence, do not exceed the label directions and let your healthcare provider monitor you.

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

Read the full Diiodothyronine monograph & all interactions
Medication

About Orlistat

What Is Orlistat Used For?

Brand names: Xenical, Alli

Xenical and prescription-strength orlistat are approved to help obese adults lose weight and keep it off when used with a reduced-calorie diet. They are intended for people with a body mass index (BMI) of 30 or higher, or 27 or higher if other risk factors such as high blood pressure, diabetes, or dyslipidemia (abnormal cholesterol or fat levels in the blood) are present.

Alli is the over-the-counter version, approved for weight loss in overweight adults 18 and older when used with a reduced-calorie, low-fat diet and exercise program.

Most-Reported Side Effects for Orlistat

From FAERS, the FDA’s public side-effect reporting system (25,755 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Rectal discharge 2,434 reports
Gastrointestinal disorder 2,186 reports
Constipation 1,991 reports
Diarrhea 1,960 reports
Weight increased 1,944 reports
See full Orlistat drug information
Keep checking

Other Drugs & Diiodothyronine

Browse every other medication we’ve checked against Diiodothyronine — 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 Diiodothyronine 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 Diiodothyronine list.

See the full Diiodothyronine interactions page
See every supplement checked against Orlistat, ranked by severity
Evidence & sources

Diiodothyronine References

The 3 sources that drive our Diiodothyronine monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Diiodothyronine is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Thyroid Hormone — MedlinePlus (U.S. National Library of Medicine) Source
  2. Dietary Supplements: What You Need to Know — NIH Office of Dietary Supplements Source
  3. Using Dietary Supplements Wisely — NIH NCCIH Source

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

Taking Diiodothyronine and Orlistat Together: Common Questions

Is it safe to take Diiodothyronine with Orlistat?
We do not list a known interaction between Diiodothyronine and Orlistat. 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.
Are Diiodothyronine and Orlistat used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Diiodothyronine in each. That is a conversation for your prescriber, especially if Orlistat is being adjusted to a target.
Does Orlistat interact with any supplements?
Yes. Orlistat has documented interactions with 18 supplements in our database — Diiodothyronine is not one of them. The Orlistat 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

Diiodothyronine monograph Uses, safety profile, and every drug interaction in one place Orlistat drug information The full plain-English guide to this medication Orlistat supplement interactions Every supplement checked against Orlistat, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Orlistat and Diiodothyronine?

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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.