Drug & supplement interaction

Ostarine + Levothyroxine Sodium

Levothyroxine Sodium brand names: Tirosint-Sol, Thyquidity, Ermez.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Ostarine and Levothyroxine Sodium 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. Additionally, although there is no interaction, the label for Levothyroxine Sodium states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Ostarine and Levothyroxine Sodium

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 Sodium and Ostarine 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.

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.

Ostarine safety at a glance

Ostarine overall Avoid Ostarine is an unapproved investigational drug with documented safety risks and no FDA approval.
Pregnancy Avoid It affects hormone pathways and must be avoided during pregnancy.
Breastfeeding Avoid There is no safety data, so avoid while breastfeeding.

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

Still wondering about combining Levothyroxine Sodium and Ostarine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Levothyroxine Sodium

Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine Sodium is filed under 3 classifications — including thyroid hormone, oral drugs. Ostarine has documented interactions with 6 drug classes — the most serious being cytochrome p450 3a4 (cyp3a4) inducers (moderate), hepatotoxic drugs (moderate) and probenecid (benemid) (moderate) — and none of Levothyroxine Sodium’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Ostarine Does Interact With Other Medications

Ostarine has 440 moderate, 171 minor known drug interactions in our database — Levothyroxine Sodium isn’t one of them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Ostarine

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

What to actually watch for

No Interaction Found — But Data Suggests Ostarine and Levothyroxine Sodium May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • A heart attack Worth acting on Additional detail

    Ostarine

    “Orally, in a 12-week study of healthy elderly patients taking ostarine daily, high-density lipoprotein (HDL) cholesterol levels decreased by 9 mg/dL and 15 mg/dL with ostarine 1 mg and 3 mg, respectively, when compared with placebo. Theoretically, reductions in HDL reported with ostarine could potentially increase the risk for adverse cardiovascular effects. In fact, the U.S.”

    Ostarine · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    5 sources cited
    1. 98833. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri
    2. 94879. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
    3. 94880. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
    4. 94881. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017
    5. 98840. FDA. FDA Warns against using SARMs in body building products. October 2017. Available at: https://www.fda.gov/newsevents/newsroom/fdainbrief/ucm583021.htm.

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›

  • Shortness of breath Worth acting on reported in 5.3% of FDA reports for Levothyroxine Sodium Additional detail

    Ostarine

    “Orally, in a 16-week study of cancer patients taking ostarine 1-3 mg daily, pneumonia occurred more frequently with ostarine than with placebo. Cough and dyspnea were also reported, but at rates slightly lower than placebo. In a 12-week study of healthy elderly patients taking ostarine 1-3 mg daily, cough occurred more frequently with ostarine than with placebo.”

    Ostarine · Natural Medicines adverse-effect record, reported in cancer.

    2 sources cited
    1. 98832. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed
    2. 98833. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Weight loss / Itching Additional detail

    Ostarine

    “Orally, in a 16-week study of cancer patients taking ostarine 1-3 mg daily, a transient increase in alanine aminotransferase (ALT) of 2- to 4-times the upper limit of normal occurred in 7.4% of patients taking ostarine 3 mg.”

    Ostarine · Natural Medicines adverse-effect record, reported in anorexia.

    6 sources cited
    1. 98832. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed
    2. 98833. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri
    3. 94879. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
    4. 94880. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
    5. 94881. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017
    6. 106197. Bedi H, Hammond C, Sanders D, Yang HM, Yoshida EM. Drug-induced liver injury from enobosarm (ostarine), a selective androgen receptor modulator. ACG Case Rep J 2021;8(1):e00518. PubMed

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›

  • Tiredness reported in 8.5% of FDA reports for Levothyroxine Sodium Additional detail

    Ostarine

    “Orally, in a 16-week study of cancer patients taking ostarine 1-3 mg daily, headache occurred more frequently with ostarine than with placebo. Fatigue was also commonly reported, but at a rate similar to placebo. In a 12-week study of healthy elderly patients taking ostarine 1-3 mg daily, headache occurred in 29% of patients, which was more common than with placebo.”

    Ostarine · Natural Medicines adverse-effect record, reported in cancer.

    5 sources cited
    1. 98832. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed
    2. 98833. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri
    3. 94879. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
    4. 94880. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
    5. 94881. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Fever Additional detail

    Ostarine

    “Orally, in a 16-week study of cancer patients taking ostarine 1-3 mg daily, pyrexia occurred more frequently with ostarine than with placebo.”

    Ostarine · Natural Medicines adverse-effect record, reported in cancer.

    1 source cited
    1. 98832. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›

  • Stomach pain / Nausea reported in 7.2% of FDA reports for Levothyroxine Sodium Additional detail

    Ostarine

    “Orally, ostarine has been commonly reported to cause gastrointestinal adverse effects. In a 16-week study of cancer patients taking ostarine 1-3 mg daily, nausea, diarrhea, constipation, abdominal pain, and anorexia occurred in 10% or more of patients, which was more common than with placebo. Vomiting was also commonly reported, although the incidence was slightly lower than placebo.”

    Ostarine · Natural Medicines adverse-effect record, reported in anorexia.

    2 sources cited
    1. 98832. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed
    2. 98833. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Diarrhea reported in 6.0% of FDA reports for Levothyroxine Sodium Additional detail

    Ostarine

    Recorded for Ostarine in the same Natural Medicines adverse-effect record shown under Stomach pain / Nausea above.

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Headache reported in 6.2% of FDA reports for Levothyroxine Sodium Additional detail

    Ostarine

    Recorded for Ostarine in the same Natural Medicines adverse-effect record shown under Tiredness above.

    Levothyroxine Sodium

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Showing the 10 most notable of 11 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Ostarine but not commonly for Levothyroxine Sodium: liver problems, a low platelet count, severe muscle breakdown and constipation.

Effects for Levothyroxine Sodium come from the ADVERSE REACTIONS section of its FDA label; effects for Ostarine come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 312,551 voluntary FDA FAERS reports for Levothyroxine Sodium that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Levothyroxine Sodium Products Have a Food Rule — Ostarine Should Not Break It

At least one FDA label for a product containing Levothyroxine Sodium says to take it on an empty stomach. Most supplements — Ostarine included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Levothyroxine Sodium on its own and move Ostarine to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Levothyroxine Sodium products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Levothyroxine Sodium

This page covers Ostarine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine Sodium 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).

Open the Levothyroxine Sodium interaction page

One more smart check

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

We hold 33 real supplement products containing Ostarine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ostarine. Even though Ostarine itself has no known interaction with Levothyroxine Sodium, 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 Ostarine and Levothyroxine Sodium 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 Ostarine
Steady interest

#1,283 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Levothyroxine Sodium
Top 5%

#126 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 Ostarine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Ostarine and Levothyroxine Sodium records this page draws on were last updated July 10, 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 Ostarine

What is Ostarine?

  • Muscle building
  • Athletic performance
  • Fat loss / body recomposition
  • Bodybuilding cycles

Ostarine (also called MK-2866 or enobosarm) is an experimental, unapproved drug known as a SARM (selective androgen receptor modulator), not a true dietary supplement. It is not approved by the FDA, is banned in sports, and has been linked to liver injury and other serious harms, so it is not recommended for general use.

Synthetic compound (not from a plant) · Capsules, tablets, liquids, powders sold as research chemicals or 'sports supplements'

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

Ostarine: dosing

There is no established safe or approved dose of Ostarine, because it is not an approved medicine or a legitimate dietary supplement. Doses used in research studies were given under medical supervision and do not apply to over-the-counter use.We do not recommend using Ostarine. Products sold online may not contain the dose listed on the label and may include other hidden substances.

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

Read the full Ostarine monograph & all interactions
Medication

About Levothyroxine Sodium

Most-Reported Side Effects for Levothyroxine Sodium

From FAERS, the FDA’s public side-effect reporting system (312,551 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 26,585 reports
Nausea 22,605 reports
Headache 19,408 reports
Diarrhea 18,759 reports
Dyspnea 16,717 reports
Keep checking

Other Drugs & Ostarine

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

0Major
440Moderate
171Minor
2,218No known interaction
Moderate

440 interactions

Showing 60 of 440 moderate interactions — see all 440 on the Ostarine page.

Minor

171 interactions

Showing 60 of 171 minor interactions — see all 171 on the Ostarine page.

No interaction 2,218 drugs checked — show the list
Evidence & sources

Ostarine References

The 10 references that drive our Ostarine 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. Warning Letter: Ironmag Labs 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582464.htm Accessed: November 1, 2017
  2. Warning Letter: Panther Sports Nutrition 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm581630.htm. Accessed: November 1, 2017
  3. Warning Letter: Infantry Labs LLC 10/23/17. FDA Inspections, Compliance, Enforcement, and Criminal Investigations, October 23, 2017. https://www.fda.gov/iceci/enforcementactions/warningletters/2017/ucm582685.htm. Accessed: November 1, 2017
  4. Dobs AS, Boccia RV, Croot CC, et al. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol 2013;14(4):335-45. PubMed
  5. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II tri
  6. Coss CC, Jones A, Dalton JT. Pharmacokinetic drug interactions of the selective androgen receptor modulator GTx-024 (enobosarm) with itraconazole, rifampin, probenecid, celecoxib and rosuvastatin. Invest New Drugs 2016;34(4):458-67. PubMed
  7. FDA. FDA Warns against using SARMs in body building products. October 2017. Available at: https://www.fda.gov/newsevents/newsroom/fdainbrief/ucm583021.htm.
  8. Bedi H, Hammond C, Sanders D, Yang HM, Yoshida EM. Drug-induced liver injury from enobosarm (ostarine), a selective androgen receptor modulator. ACG Case Rep J 2021;8(1):e00518. PubMed
  9. Kintz P, Gheddar L, Paradis C, et al. Peroxisome Proliferator-Activated Receptor Delta Agonist (PPAR- d) and Selective Androgen Receptor Modulator (SARM) Abuse: Clinical, Analytical and Biological Data in a Case Involving a Poisonous Combination of GW1516
  10. Weinblatt D, Roy S. Drug-Induced Liver Injury Secondary to Enobosarm: A Selective Androgen Receptor Modulator. J Med Cases 2022;13(5):244-248. 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

Taking Ostarine and Levothyroxine Sodium Together: Common Questions

Is it safe to take Ostarine with Levothyroxine Sodium?
We do not list a known interaction between Ostarine and Levothyroxine Sodium. 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.
Do Ostarine and Levothyroxine Sodium have any of the same side effects?
Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Ostarine and Levothyroxine Sodium at the same time of day?
At least one FDA label for a product containing Levothyroxine Sodium says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Levothyroxine Sodium on its own and move Ostarine to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Ostarine and Levothyroxine Sodium combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine Sodium is filed under 3 classifications, and Ostarine has documented interactions with 6 drug classes — none of Levothyroxine Sodium's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Ostarine interact with any other medications?
Yes. Ostarine has 611 documented drug interactions in our database — Levothyroxine Sodium is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Levothyroxine Sodium interact with any supplements?
Yes. Levothyroxine Sodium has documented interactions with 50 supplements in our database — Ostarine is not one of them. The Levothyroxine Sodium interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Levothyroxine Sodium and Ostarine?

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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.