Published: 2 October 2026. Last reviewed: 2 October 2026.
Reading time: about 15 minutes.
For decades, a person told they had NASH with liver scarring heard the same advice: lose weight, exercise, control blood sugar and come back in a year.
That advice is still correct, but it left a gap. Many patients could not reach or hold the weight loss needed to reverse liver damage, and no medicine had been approved to treat the disease itself.
That changed on 14 March 2024, when the US Food and Drug Administration approved Resmetirom, marketed as Rezdiffra, for adults with NASH and moderate to advanced fibrosis.
It was the first approval of its kind, and it opened a new chapter in how doctors approach fatty liver disease that has already begun to scar.
This guide explains what Resmetirom is, how it works, what the clinical trials showed, who may be suitable, and what to ask your doctor.
It is written for patients, caregivers and anyone researching liver fibrosis treatment in 2026. It is educational and does not replace advice from your own doctor.
Fatty liver disease means extra fat has built up inside liver cells. In many people it stays quiet and causes no lasting harm.
In a smaller group, the fat triggers inflammation and cell injury. This more aggressive form is called NASH, short for non-alcoholic steatohepatitis.
In 2023, international liver societies agreed on new names to reduce stigma and better describe the cause. Fatty liver disease linked to metabolic risk factors is now called MASLD (metabolic dysfunction-associated steatotic liver disease).
The inflamed, injured form is now called MASH (metabolic dysfunction-associated steatohepatitis). Most research papers and clinic notes in 2026 use MASH, while many patients and search engines still use NASH.
This guide uses NASH and MASH to mean the same condition.
MASLD is among the most common liver conditions worldwide. Estimates suggest roughly one in three adults has some degree of fatty liver, and the rate is rising alongside obesity and type 2 diabetes.
South Asia carries a heavy burden. Studies from India report fatty liver in a large share of urban adults, including many people who are not obviously overweight.
Risk factors include:
Early NASH rarely causes symptoms. Many people feel well while scarring slowly builds.
When symptoms appear, such as tiredness, discomfort in the upper right abdomen or swelling, the disease may already be advanced.
This is why screening people with diabetes, obesity or abnormal liver tests matters so much.
Scarring of the liver, called fibrosis, is the single most important predictor of long-term outcomes in NASH.
Advanced fibrosis can progress to cirrhosis, liver failure, liver cancer and the need for transplant. People with NASH also face higher rates of heart disease, which is often a bigger threat than the liver itself.
For these reasons, treatment aims to stop or reverse fibrosis, not only to reduce liver fat.
Doctors grade fibrosis from stage 0 to stage 4. The stage guides treatment decisions, including whether Resmetirom is appropriate.
| Stage | Meaning | Approximate outlook |
|---|---|---|
| F0 | No scarring | Lifestyle care and risk factor control |
| F1 | Mild scarring | Lifestyle care, regular monitoring |
| F2 | Moderate scarring | Needs active management; may qualify for medicine |
| F3 | Advanced scarring (bridging fibrosis) | High risk of progression; may qualify for medicine |
| F4 | Cirrhosis | Specialist care; Resmetirom is not approved for this group |
The approved population for Rezdiffra in the United States is F2 to F3. That is the group where scarring is significant but the liver has not yet reached cirrhosis.
A liver biopsy was once the only way to stage fibrosis. Today, most patients are assessed with non-invasive tools first:
No single non-invasive test is perfect. Your specialist combines results with your history and risk profile.
NASH was first described in the medical literature in 1980. For more than four decades, the main treatment was lifestyle change, plus a few off-label options in selected patients.
Many promising drug candidates failed in late-stage trials. Several reasons explain why NASH has been so hard to treat.
Resmetirom was the first drug to clear the regulatory bar by showing biopsy-proven benefit in a large phase 3 trial.
Resmetirom, also known by the development code MGL-3196, is a once-daily oral tablet. It was developed by Madrigal Pharmaceuticals and is sold under the brand name Rezdiffra.
It belongs to a class called thyroid hormone receptor beta (THR-beta) agonists. In plain terms, it switches on a specific pathway in the liver that helps the organ handle fat.
It is not a thyroid medicine for people with an underactive thyroid, and it is not a weight-loss drug, although some patients do lose a little weight.
| Generic name | Resmetirom |
| Brand name | Rezdiffra |
| Drug class | Thyroid hormone receptor beta agonist |
| Form | Oral tablet, once daily |
| US FDA approval | 14 March 2024 |
| Approved use | Noncirrhotic NASH (MASH) with moderate to advanced fibrosis (F2 to F3), with diet and exercise |
| Prescription status | Prescription only |
Thyroid hormone controls metabolism throughout the body. There are different receptor types, and they behave differently in different organs.
THR-alpha receptors are found mainly in the heart, bone and brain. THR-beta receptors are found mostly in the liver.
Earlier attempts to use thyroid hormone to treat fatty liver caused side effects in the heart and bone. Resmetirom was designed to act mainly on the liver receptor, which limits those effects.
When Resmetirom activates THR-beta, several useful changes occur:
Less fat means less cell stress, which in turn may reduce inflammation and the signals that drive scarring.
People with NASH often have abnormal blood fats and a high risk of heart attack and stroke. A medicine that treats the liver and also lowers atherogenic lipids is attractive.
Resmetirom is not approved as a cholesterol drug, and it should not replace a statin if your doctor has prescribed one. It is a liver treatment with a helpful side benefit.
The approval of Rezdiffra rests on a programme of studies. Here is what they showed, in plain language.
A 36-week phase 2 trial published in The Lancet in 2019 enrolled adults with biopsy-confirmed NASH. Patients taking Resmetirom had a larger reduction in liver fat measured by MRI-PDFF than patients taking placebo.
The study also showed improvements in liver enzymes and in blood fats. This gave the first strong signal that the approach could work.
This 52-week phase 3 safety study enrolled a large group of patients with presumed NAFLD or NASH. It evaluated safety and tolerability at 80 mg and 100 mg, along with changes in liver fat, LDL cholesterol and other markers.
Results supported the safety profile of the drug and showed reductions in liver fat and atherogenic lipids.
MAESTRO-NASH is the study that supported approval. It enrolled adults with biopsy-confirmed NASH and fibrosis stage F1B, F2 or F3, and compared Resmetirom 80 mg, Resmetirom 100 mg and placebo.
The results were published in the New England Journal of Medicine in 2024. At 52 weeks, biopsies were repeated and two main outcomes were measured.
| Outcome at 52 weeks | Placebo | Resmetirom 80 mg | Resmetirom 100 mg |
|---|---|---|---|
| NASH resolution with no worsening of fibrosis | 9.7% | 25.9% | 29.9% |
| Fibrosis improvement by at least one stage with no worsening of NAFLD activity score | 14.2% | 24.2% | 25.9% |
Both outcomes were significantly better with Resmetirom than with placebo. LDL cholesterol also fell by roughly 13 to 16 percent at week 24 in the Resmetirom groups, while it was unchanged in the placebo group.
These figures are encouraging, but they need context so that expectations stay realistic.
The MAESTRO-NASH OUTCOMES study is following patients with compensated NASH cirrhosis to see whether Resmetirom reduces clinical events such as decompensation. Results from studies like this will clarify the long-term value of the drug and whether its use should widen.
Check with your doctor for the latest published data, because this field moves quickly.
The US FDA granted accelerated approval to Rezdiffra in March 2024 based on the biopsy results, with continued approval linked to confirmation of clinical benefit in ongoing trials.
The European Commission later granted conditional marketing authorisation for adults with noncirrhotic MASH and moderate to advanced fibrosis. Other regulators have been reviewing the drug at different speeds.
Approval status, labelling and availability differ by country and can change. If you live in India or another market outside the US and EU, ask your hepatologist or gastroenterologist about the current legal and supply situation in your country rather than relying on a general article.
In the United States, the approved indication is for adults who meet all of the following:
Your doctor will decide, but the following situations need particular care:
Fatty liver can coexist with alcohol-related liver disease, viral hepatitis, autoimmune hepatitis, hemochromatosis and drug-induced liver injury. These need to be excluded or treated first.
Alcohol use in particular must be discussed openly, since it speeds scarring and can confuse the picture.
The dose of Rezdiffra in the US label depends on body weight. Your doctor decides the exact dose, so treat the following as general information.
| Body weight | Recommended once-daily dose |
|---|---|
| Under 100 kg (220 lb) | 80 mg |
| 100 kg (220 lb) or more | 100 mg |
If you take a moderate CYP2C8 inhibitor such as clopidogrel, the label recommends a lower dose of Resmetirom. Strong CYP2C8 inhibitors such as gemfibrozil should be avoided.
Always give your doctor and pharmacist a full list of prescription medicines, over-the-counter products and supplements before starting.
NASH is a chronic condition, so treatment is generally long term. Your doctor will review benefit and tolerability at regular intervals and may use repeat liver stiffness testing to see whether fibrosis is stable or improving.
Most side effects in clinical trials were mild to moderate and often appeared early in treatment.
Diarrhea and nausea were reported more often than with placebo, especially in the first few months. Staying hydrated and talking to your doctor early can help manage them.
Rezdiffra is processed by the liver, and liver injury has been reported with the drug. Your doctor may check liver tests before and during treatment and may stop the medicine if signs of injury appear.
Cholelithiasis (gallstones) and cholecystitis were more common in treated patients. If you already have gallstones or have had gallbladder problems before, discuss this with your doctor.
Medicine added to an unchanged lifestyle is unlikely to give the best result. In the trials, everyone was counselled on diet and exercise, and the label specifies use alongside them.
Interactions are one of the most practical issues with Resmetirom, because people with NASH often take several other medicines for diabetes, blood pressure and cholesterol.
Resmetirom can raise blood levels of some statins. The US label sets maximum daily doses when combined with Resmetirom:
| Statin | Maximum daily dose with Resmetirom (US label) |
|---|---|
| Rosuvastatin | 20 mg |
| Simvastatin | 20 mg |
| Pravastatin | 40 mg |
| Atorvastatin | 40 mg |
Do not reduce or stop a statin on your own. Heart protection is important in NASH, and your doctor can adjust the plan.
If you want background on one of the commonly used statins, read our guide on how generic atorvastatin is used and purchased. Any dose changes must still come from your prescriber.
Resmetirom is broken down partly by the CYP2C8 enzyme.
Medicines such as cyclosporine can raise Resmetirom levels and should be avoided during treatment according to the label.
Many patients with NASH also have type 2 diabetes or high blood pressure. Medicines for these conditions are used alongside liver treatment, and each needs review.
These links are for background reading. They do not tell you that a combination is safe for you. Ask your prescriber and pharmacist to check your whole medicine list.
Herbal products, supplements, over-the-counter pain relievers and medicines from another doctor can all change how a liver-processed drug behaves. Keep a written list and bring it to every appointment.
Our FAQ page explains how to prepare questions about your medicines.
Starting Resmetirom is the beginning of a care plan, not the end of one.
If scarring advances to cirrhosis, your specialist will reassess the plan. Cirrhosis requires surveillance for liver cancer and varices, and the benefit-risk balance of Resmetirom changes.
Resmetirom is not the only tool for NASH. Treatment is usually layered, and the right mix depends on your fibrosis stage, weight, diabetes status and other conditions.
| Option | What it does | Key points |
|---|---|---|
| Lifestyle change | Reduces liver fat and inflammation through weight loss, diet and exercise | Foundation for every patient; losing 7 to 10 percent of body weight is linked with improvement in NASH |
| Resmetirom (Rezdiffra) | Liver-targeted THR-beta agonist | Approved for F2 to F3 noncirrhotic MASH; oral once-daily tablet |
| Semaglutide (Wegovy) | GLP-1 receptor agonist that supports weight loss and improves metabolic health | The FDA approved it for MASH with F2 to F3 fibrosis in August 2025; injectable |
| Pioglitazone | Improves insulin sensitivity | Used in selected patients with biopsy-proven NASH; can cause weight gain and fluid retention |
| Vitamin E | Antioxidant | Considered in selected non-diabetic adults with biopsy-proven NASH; long-term safety needs discussion |
| SGLT2 inhibitors and other diabetes medicines | Treat diabetes and may help liver enzymes and fat | Chosen mainly for diabetes and heart or kidney benefits |
| Bariatric surgery | Large and sustained weight loss | Option for eligible patients with obesity; can improve NASH and fibrosis |
Doctors often combine lifestyle care with one or more medicines. Whether it is appropriate to combine Resmetirom with a GLP-1 medicine or another agent is a specialist decision, since evidence on combinations is still developing.
A person with obesity, diabetes and fibrosis may benefit from a weight-focused plan. A person with a lean build and fibrosis may lean toward a different approach.
This is why a hepatologist or experienced gastroenterologist should guide the choice.
Every guideline, and the Rezdiffra label itself, places diet and exercise at the centre of NASH care. No tablet works in isolation.
Studies show that losing about 5 percent of body weight can reduce liver fat, 7 to 10 percent can improve inflammation, and 10 percent or more can improve fibrosis in many patients.
Slow, steady loss of about 0.5 to 1 kg per week is generally safer than crash dieting, which can worsen liver inflammation.
Alcohol adds to liver injury. Many specialists advise people with significant fibrosis to avoid alcohol altogether. Ask your doctor for personal advice.
Poor sleep and untreated sleep apnea are linked with worse liver outcomes. Smoking raises the risk of fibrosis progression and cardiovascular disease.
Addressing them is part of a complete plan.
Rezdiffra is a specialty medicine. At launch in the United States, the list price was about 47,400 US dollars per year, and the actual cost to patients depends on insurance, assistance programmes and local pricing.
Prices, supply and approvals differ widely by country and change over time. Confirm current details with your doctor, hospital pharmacy or insurer.
Resmetirom is a prescription-only medicine. It should be started and monitored by a qualified doctor after fibrosis has been staged and other conditions and medicines have been reviewed.
Be careful with any website or seller that offers prescription-only liver medicines without asking for a valid prescription or that makes guaranteed cure claims. Counterfeit and substandard medicines are a real risk in online markets, and for a long-term treatment the consequences of getting this wrong can be serious.
At My Online Med Shop, we publish educational guides to help patients understand their medicines and ask better questions.
Return to the My Online Med Shop home page for all categories.
Fact: Early disease is often silent. Fibrosis can advance without symptoms, so testing is the only way to know.
Fact: The approval is for use together with diet and exercise. Lifestyle change remains the foundation.
Fact: People with a normal body mass index can develop it, especially those with insulin resistance, central fat or certain genetic risks. South Asians are at particular risk at lower body weights.
Fact: It targets the liver-specific thyroid hormone receptor beta. It is not meant to treat an underactive thyroid.
Fact: Trials showed that a meaningful share of patients improved, but not everyone responds. The word cure is not appropriate, and long-term outcome data are still being collected.
Fact: There is no good evidence that detox products reverse fibrosis, and some herbal products can injure the liver.
Fact: Liver enzymes can be normal even with significant fibrosis. Fibrosis testing, not enzymes alone, tells the story.
Use this list at your next appointment.
Resmetirom is used in adults with noncirrhotic NASH (MASH) who have moderate to advanced liver fibrosis, stages F2 to F3. It is taken together with diet and exercise. It was approved by the US FDA on 14 March 2024.
Yes. In 2023, liver societies renamed NASH to MASH, which stands for metabolic dysfunction-associated steatohepatitis. The condition is the same, and both names are still in use.
It activates thyroid hormone receptor beta in the liver. This helps liver cells burn more fat and reduces fat stored in the liver, which may lessen inflammation and scarring over time.
In the MAESTRO-NASH trial at 52 weeks, NASH resolution occurred in 25.9 percent (80 mg) and 29.9 percent (100 mg) of patients, compared with 9.7 percent on placebo. Fibrosis improved in 24.2 and 25.9 percent, compared with 14.2 percent on placebo.
It is not approved for cirrhosis. Studies in patients with cirrhosis are ongoing, and no conclusion should be drawn until the results are published and reviewed by regulators.
The US label recommends 80 mg once daily for people under 100 kg and 100 mg once daily for people weighing 100 kg or more. Your doctor sets the dose for you.
Diarrhea and nausea are most common. Itching, vomiting, constipation, abdominal pain and dizziness are also reported. Seek medical help for yellow skin or eyes, dark urine or severe upper right abdominal pain.
Often yes, but with limits on certain statins. The label caps rosuvastatin and simvastatin at 20 mg and pravastatin and atorvastatin at 40 mg per day. Do not change doses without your prescriber.
Yes. Diet, exercise and weight management are the foundation of NASH care, and the medicine is intended as an addition, not a replacement.
NASH is long term, so treatment is generally ongoing as long as it is helping and tolerated. Your doctor will review progress and decide on duration.
No. It is a prescription-only medicine, and it should be started after a doctor confirms the diagnosis and stage of liver disease.
Approval and supply status vary by country and can change. Ask your hepatologist or gastroenterologist about the current situation in India before making plans around this medicine.
Alcohol harms the liver, and many specialists advise people with significant fibrosis to avoid it. Discuss your own situation with your doctor.
The two work differently and were studied in different trials, so a direct comparison is not possible from current data. The right choice depends on your weight, diabetes, heart risk and other factors, and is best made with your specialist.
Data are limited. Speak with your doctor before using it if you are pregnant, planning pregnancy or breastfeeding.
Resmetirom (Rezdiffra) marks a milestone: after decades with no approved medicine, adults with NASH and moderate to advanced fibrosis now have a treatment backed by biopsy data from a large phase 3 trial.
It is not a cure, it does not work for everyone, and it carries real considerations around side effects, gallbladder health and drug interactions. It works best as part of a complete plan that includes weight management, nutritious food, regular exercise and control of diabetes, blood pressure and cholesterol.
If you have been told you have fatty liver, ask about your fibrosis stage. The earlier scarring is found, the more options you have.
For more patient-friendly health education, explore our blog library, browse the product catalogue, or reach out through the contact page if you have a question about a medicine or an order.
The following are the primary sources used for this article. Readers are encouraged to review them directly.
This article is for general education and does not replace advice, diagnosis or treatment from a qualified healthcare professional. Prescribing information, approvals, pricing and availability differ between countries and can change after the publication date.
Do not start, stop or change any medicine without speaking to your doctor. If you think you may be having a medical emergency, contact your local emergency services immediately.
Mentions of other medicines and linked articles are provided for background reading and do not mean that any product is suitable for you.
Resmetirom (Rezdiffra) for NASH: The Breakthrough Treatment After 25 Years | Complete Guide to Liver Fibrosis Treatment 2026
Can You Safely Drink Alcohol While Taking GLP-1 Medications? Why Pharmacists Are Issuing Urgent Warnings (Ozempic, Wegovy, Mounjaro 2026)
The FDA Just Issued Its Most Serious Recall Warning for a Thyroid Medication Millions of Americans Take Daily — Is Your Bottle Affected? (2026)
Why GLP-1 Weight Loss Drugs Are Causing Unexpected Pregnancies: "Ozempic Babies" & Hidden Menstrual Changes (What 67,000 Reddit Users Revealed)