Drug & supplement interaction

Ostarine + Isoniazid, Rifampin

Isoniazid, Rifampin brand name: Rifamate.

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

Isoniazid, Rifampin falls into 4 drug categories that Ostarine can interact with; the most serious is rated moderate. Theoretically, concomitant use with hepatotoxic drugs might increase the risk of adverse hepatotoxic effects.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Ostarine and Isoniazid, Rifampin

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Ostarine interacts with whole categories of medication. Isoniazid, Rifampin falls into 4 of those categories, so it can interact with Ostarine in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

HEPATOTOXIC DRUGS

1 of 4

Why this applies to Isoniazid, Rifampin

Isoniazid, Rifampin falls under HEPATOTOXIC DRUGS — the group Ostarine interacts with.

Theoretically, concomitant use with hepatotoxic drugs might increase the risk of adverse hepatotoxic effects.
Some clinical research shows that ostarine can increase alanine aminotransferase, a marker of liver damage, in some patients. Additionally, the U.S. Food and Drug Administration warns that supplements containing SARMs, such as ostarine, have been associated with reports of liver toxicity and there are at least two reports of drug-induced liver injury attributed to the use of ostarine.
Severity Moderate Likelihood Possible Evidence D

Interaction 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.

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

Here's the concern with pairing Ostarine and Rifamate (which combines isoniazid and rifampin). Both of these tuberculosis medicines are already known to be tough on the liver. Isoniazid in particular can cause liver inflammation, and doctors usually monitor liver enzymes while you take it. Ostarine has its own track record of raising liver markers like ALT, and the FDA has flagged real reports of liver injury from SARMs.

So the worry isn't that one changes how the other is broken down. It's that stacking two liver stressors together could add up. Watch for yellowing of the skin or eyes, dark urine, nausea, belly pain, or unusual tiredness. This is a theoretical concern based on how each behaves, but please talk with your doctor or pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  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. 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
  7. 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
Moderate

CYTOCHROME P450 3A4 (CYP3A4) INDUCERS

2 of 4

Isoniazid, Rifampin also falls under CYTOCHROME P450 3A4 (CYP3A4) INDUCERS.

Theoretically, concomitant use of ostarine with CYP3A4 inducers could decrease the clinical effects of ostarine.
Ostarine is partially metabolized by CYP3A4. Clinical research shows that taking rifampin, a potent inducer of CYP3A4, reduces the maximum plasma concentration of ostarine by 23% and the area under the curve by 43%.
Severity Moderate Likelihood Possible Evidence B

Interaction 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.

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

Here's what's going on with this combo. Rifampin (the rifampin part of Rifamate) is one of the strongest known 'speed-up' agents for a liver enzyme called CYP3A4. Ostarine is partly broken down by that same enzyme, so when rifampin revs it up, your body clears Ostarine faster. In a study, this dropped Ostarine's peak blood level by about 23% and total exposure by roughly 43%. In plain terms, you'd likely get less effect from the Ostarine, not more.

Honestly, my bigger concern is safety, not lost benefit. Both Ostarine and isoniazid are known to stress the liver, and stacking two liver-taxing products is a real worry. Please talk with your doctor or pharmacist before combining these.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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
Moderate

RIFAMPIN (Rifadin)

3 of 4
Theoretically, concomitant use of ostarine with rifampin could decrease the clinical effects of ostarine.
Clinical research shows that taking rifampin with ostarine reduces the maximum plasma concentration of ostarine by 23% and the area under the curve by 43%. Ostarine is partially metabolized by cytochrome P450 3A4 (CYP3A4), and rifampin is a potent CYP3A4 inducer.
Severity Moderate Likelihood Possible Evidence B

Interaction 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.

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

Here's what's going on with this combo. Rifampin (one of the two drugs in Rifamate) is a strong 'speed-up' signal for a liver enzyme called CYP3A4, which happens to be one of the enzymes that breaks down Ostarine. In a clinical study, taking rifampin alongside Ostarine cut Ostarine's peak blood level by about 23% and its total exposure by roughly 43%. In plain terms, rifampin makes your body clear Ostarine faster, so you'd likely get less of whatever effect you were hoping for from it.

This isn't really a safety alarm in the usual sense, but I'll be honest: Ostarine is an unapproved SARM linked to liver injury, and isoniazid and rifampin can also stress the liver. Stacking them is not something I'd recommend. Please loop in your doctor or pharmacist before mixing these.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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
Minor

CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS

4 of 4

Isoniazid, Rifampin also falls under CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS.

Theoretically, concomitant use of ostarine with CYP3A4 inhibitors could increase the effects and adverse effects of ostarine, although this is unlikely to be clinically significant.
Ostarine is partially metabolized by CYP3A4. However, clinical research shows that taking itraconazole, a potent inhibitor of CYP3A4, had minimal effects on the levels of ostarine in the body.
Severity Minor Likelihood Unlikely Evidence B

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Here's the wrinkle with Rifamate (isoniazid plus rifampin): it's actually a mixed bag for liver enzymes. Isoniazid can slow down CYP3A4, while rifampin is a strong enzyme inducer that speeds many of them up. On paper, the slowing-down piece could let a bit more Ostarine linger in your body, which might bump up its effects and side effects. But honestly, this is theoretical and rated minor and unlikely. When researchers tested Ostarine with a very strong CYP3A4 blocker, the levels barely budged.

The bigger concern isn't really the enzymes, it's the liver. Both Rifamate and Ostarine can stress or injure the liver on their own, so stacking them is asking for trouble. Please talk with your doctor or pharmacist before mixing these.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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

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

Ostarine Also Interacts With Other Medications

Ostarine has 439 moderate, 171 minor known drug interactions in our database — the Isoniazid, Rifampin one above is among them. If you take anything else, check it against the full list below.

Moderate 439 Minor 171 No known interaction 2,220 (incl. Isoniazid, Rifampin)
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.

Everything else you take

See Every Supplement That Interacts With Isoniazid, Rifampin

This page covers Ostarine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Isoniazid, Rifampin page lists 145 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Asarabacca (major), Beer (major) and Grapefruit (major).

By severity: 8 major · 117 moderate · 20 minor.

From our pharmacist’s overview on the Isoniazid, Rifampin page

“Rifamate combines isoniazid and rifampin, the backbone of tuberculosis treatment, and both drugs are hard on the liver, which is why this list of 145 supplement and herbal interactions deserves genuine respect. Eight entries rate major, and the largest cluster, 38 ingredients, adds to that same liver strain, with alcohol in beer or win…”

Reviewed by 2 · Jul 18, 2026

Open the Isoniazid, Rifampin 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. Your product may carry other ingredients that interact with Isoniazid, Rifampin too, on top of Ostarine — 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 Ostarine and Isoniazid, Rifampin 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

#1,063 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Isoniazid, Rifampin
Top half

#732 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 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.

Read the full Ostarine monograph & all interactions
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
439Moderate
171Minor
2,219No known interaction
439 Moderate 171 Minor 2,219 No interaction
Moderate

439 interactions

Showing 60 of 439 moderate interactions — see all 439 on the Ostarine page.

Minor

171 interactions

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

No interaction 2,219 drugs checked — show the list

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

Showing the 60 most looked-up of 2,219 medications checked with no known interaction — see the full Ostarine list.

See the full Ostarine interactions page
See every supplement checked against Isoniazid, Rifampin, 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
Ostarine monograph › Uses, safety, and every drug interaction in one place Isoniazid, Rifampin supplement interactions › Every supplement checked against Isoniazid, Rifampin, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Ostarine and Isoniazid, Rifampin Together: Common Questions

Can you take Ostarine with Isoniazid, Rifampin?
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.
Why are there 4 interactions listed for Ostarine and Isoniazid, Rifampin?
Isoniazid, Rifampin belongs to more than one drug category, and Ostarine interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Ostarine and Isoniazid, Rifampin 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

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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.