AI Summary Resmetirom (Rezdiffra) is the first and only FDA-approved THR-β agonist for MASH with moderate to advanced fibrosis, approved in March 2024.
Medically reviewed.
THR-β agonist therapy is a class of liver-directed medications used to treat metabolic dysfunction-associated steatohepatitis (MASH), formerly known as NASH. These medicines activate thyroid hormone receptor-beta in liver cells to help reduce fat buildup, ease inflammation, and improve fibrosis (scarring).
Resmetirom (Rezdiffra) is currently the only FDA-approved medication in this class. This page explains how THR-β agonist therapy works, who it is for, and what to expect during treatment. You can also connect with a liver specialist to discuss whether it fits your care plan.
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THR-β AGONIST THERAPY OVERVIEW
THR-β agonist therapy is a class of liver-directed treatments used to manage metabolic dysfunction-associated steatohepatitis (MASH), a condition where fat buildup, inflammation, and scarring can damage the liver over time. Care for MASH typically combines lifestyle changes, targeted medication, and regular monitoring to track how the liver responds. Treatment plans are personalized based on how advanced the liver disease is, a person's overall health, and their individual needs, so no single approach looks the same for every patient.
You can explore the treatment options available for THR-β agonist therapy and learn how they may support liver fat reduction, inflammation control, and fibrosis management. Because the right approach depends on your specific diagnosis and health history, connecting with a liver specialist can help you understand which options fit your care plan and ensure ongoing monitoring as treatment progresses.
Resmetirom works directly in the liver to reduce fat buildup, ease inflammation, and improve or stabilize fibrosis. It may also lower LDL ("bad") cholesterol. Unlike GLP-1 medications, it is not a diabetes or weight-loss drug.
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Providers typically consider this therapy for adults with confirmed MASH and fibrosis stage F2-F3 without cirrhosis, especially when diet and exercise alone haven't slowed liver fat buildup, inflammation, or fibrosis progression, or when someone is at risk of the disease advancing toward cirrhosis.
DIET & LIFESTYLE SUPPORT
THR-β agonist therapy works best when combined with lifestyle changes. Nutrition, physical activity, weight management, and control of related metabolic conditions all support the liver health benefits of medication.
A calorie-appropriate, liver-friendly diet supports the fat and inflammation reduction that resmetirom targets in the liver.
Managing related conditions such as diabetes, high cholesterol, and high blood pressure remains an essential part of MASH care alongside medication.
Regular physical activity supports metabolic health and works alongside medication to help manage MASH.
A nutrition bar designed for liver health can be a simple, consistent way to help meet daily energy and protein goals alongside medication.
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TREATMENT MONITORING
Regular monitoring helps your healthcare provider evaluate how your liver is responding to Resmetirom and identify changes over time. Follow-up care may include blood tests, imaging, and fibrosis assessments to track liver health and guide ongoing care.
Liver function tests track enzymes and other markers that show how your liver is responding to treatment and help flag any changes early.
Providers use metabolic markers alongside liver tests to track liver fat, inflammation, and fibrosis over time and confirm resmetirom is working.
Imaging and, in selected cases, biopsy can assess fibrosis directly and help guide dosage adjustments during long-term therapy.
Only a qualified healthcare provider can adjust your treatment plan based on your test results and health history.
COMMON QUESTIONS
THR-β agonist therapy is a class of liver-directed medications used to treat metabolic dysfunction-associated steatohepatitis (MASH), formerly called NASH. Resmetirom (Rezdiffra) is currently the only FDA-approved medication in this class, prescribed for adults with moderate to advanced fibrosis (stage F2-F3) who do not have cirrhosis. It works by activating thyroid hormone receptor-beta in liver cells to help reduce fat, ease inflammation, and improve fibrosis. Talk with your liver specialist to see if this therapy fits your treatment plan.
Resmetirom activates thyroid hormone receptor-beta (THR-β) directly in liver cells, which increases the liver's ability to metabolize fat. This helps reduce excess fat buildup, ease inflammation, and improve or stabilize fibrosis (scarring) associated with MASH. Unlike GLP-1 medications, resmetirom is not primarily a diabetes or weight-loss drug, though it may also help lower LDL ("bad") cholesterol. Your healthcare provider can explain how this mechanism applies to your specific liver condition and treatment goals.
Healthcare providers generally consider THR-β agonist therapy for adults with confirmed MASH and moderate to advanced fibrosis (stage F2-F3) who do not have cirrhosis. Candidates typically have had limited improvement from diet and exercise alone, or are at risk of their liver disease progressing. Eligibility depends on your fibrosis stage, overall health, and treatment history. Only a qualified healthcare provider can determine whether resmetirom (Rezdiffra) or another approach is right for your specific situation.
In the phase 3 MAESTRO-NASH trial, 30% of participants taking the 100 mg dose of resmetirom achieved MASH resolution with no worsening of fibrosis, compared with 10% on placebo. This shows a meaningful benefit for many patients, though results vary by individual. Effectiveness depends on factors such as fibrosis stage and adherence to treatment. Discuss your specific expectations and monitoring plan with your healthcare provider.
The most commonly reported side effects of resmetirom are gastrointestinal, including diarrhea, nausea, vomiting, and abdominal discomfort. Some patients also notice itching (pruritus), dizziness, or changes in liver function test results. In clinical trials, most side effects were mild to moderate, and many digestive symptoms improved within the first few weeks of treatment. Your healthcare provider will monitor you regularly and can help manage any side effects that arise.
No, THR-β agonist therapy works alongside lifestyle changes rather than replacing them. A liver-friendly diet, regular physical activity, weight management, and control of related conditions like diabetes and high cholesterol remain essential parts of MASH care. Resmetirom (Rezdiffra) can help reduce liver fat, inflammation, and fibrosis, but it works best when combined with these ongoing habits. Ask your healthcare provider how to build a plan that pairs medication with lifestyle support.
No, THR-β agonist therapy is not the same as thyroid hormone replacement medication used for hypothyroidism. Resmetirom (Rezdiffra) selectively activates thyroid hormone receptor-beta mainly in liver cells, targeting liver fat and fibrosis rather than overall thyroid hormone levels. It is also not a diabetes or weight-loss medication. If you already take thyroid medication, tell your healthcare provider so they can coordinate your care safely.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.
