GLP-1 for Fatty Liver & MASH: The Patient Action Plan

If your hepatologist or primary-care clinician has told you that you have fatty liver — now formally called MASLD (metabolic dysfunction-associated steatotic liver disease) or, with active inflammation, MASH (metabolic dysfunction-associated steatohepatitis) per the 2023 Rinella nomenclature update^[1] — the practical question is no longer “is there a drug?” The practical question is which drug, when, and in what order. As of May 2026 there are two FDA-approved oral or injectable agents for the active inflammatory form of fatty liver disease: resmetirom (Rezdiffra), approved March 2024 based on MAESTRO-NASH^[6], and semaglutide 2.4 mg weekly (Wegovy), approved August 2025 for non-cirrhotic MASH with moderate-to-advanced fibrosis based on the ESSENCE Phase 3 trial^[4]. Tirzepatide has positive Phase 2 data (SYNERGY-NASH^[5]) but is not yet FDA-approved for the liver indication. This article walks through how a hepatologist actually stages your disease, who gets Wegovy vs Rezdiffra vs both, what lab work to expect, and the decisions you should be ready for at your next visit.

Step 1: the terminology actually changed in 2023

If you are reading older patient materials, the language has shifted. The multisociety Delphi consensus published in Hepatology in 2023 (Rinella et al.^[1]) replaced two decades of acronyms:

• NAFLD (nonalcoholic fatty liver disease) became MASLD (metabolic dysfunction-associated steatotic liver disease).
• NASH (nonalcoholic steatohepatitis) became MASH (metabolic dysfunction-associated steatohepatitis).
• The new diagnostic anchor is the presence of at least one cardiometabolic risk factor (overweight or obesity, prediabetes or type 2 diabetes, hypertension, elevated triglycerides, or low HDL) alongside hepatic steatosis on imaging or biopsy.

The clinical recommendations did not change with the renaming. AASLD published a 2024 update (Kanwal^[3]) mapping the 2023 Practice Guidance (Rinella^[2]) onto the new terminology. The drugs, dosing, monitoring, and lifestyle guidance are the same. If your chart says NAFLD or NASH, it means the same thing as MASLD or MASH — the labels just got rewritten in late 2023.

Step 2: fibrosis staging is the number that drives every decision

Fatty liver disease is staged on two axes. The first is inflammation grade (how active the steatohepatitis is). The second — and the one that matters most for treatment decisions — is fibrosis stage, scored F0 through F4:

• F0: no fibrosis. Steatosis (fat) may be present, but no scarring.
• F1: mild fibrosis confined to the portal tract or the pericellular regions.
• F2: moderate fibrosis with bridging beginning to form between portal tracts.
• F3: advanced bridging fibrosis. Architectural distortion of the lobule.
• F4: cirrhosis. Regenerative nodules and extensive fibrous bands.

Most modern hepatology practice does not biopsy first. The usual sequence is a non-invasive screen with FIB-4 (a simple calculator using age, AST, ALT, and platelet count), followed by vibration-controlled transient elastography (FibroScan) for liver stiffness and MRI-PDFF (proton density fat fraction) for steatosis quantification. Liver biopsy is reserved for cases where non-invasive testing is discordant or where a clinical trial requires histology. The AASLD 2023 Practice Guidance^[2] codifies this risk-stratification approach.

Step 3: the FDA-approved options as of May 2026

Two drugs are currently FDA-approved with a liver indication:

Resmetirom (Rezdiffra). Approved March 2024 for non-cirrhotic adults with MASH and moderate-to-advanced fibrosis (F2 or F3) on the basis of MAESTRO-NASH (Harrison 2024 NEJM^[6]). Resmetirom is a once-daily oral thyroid hormone receptor-beta agonist. It is not a GLP-1, does not affect weight, and does not affect glucose. In MAESTRO-NASH, MASH resolution at week 52 was 25.9% on the 80 mg dose and 29.9% on the 100 mg dose, vs 9.7% on placebo. Fibrosis improvement of at least one stage without worsening of MASH was 24.2% (80 mg) and 25.9% (100 mg) vs 14.2% placebo.

Semaglutide 2.4 mg weekly (Wegovy). Approved August 2025 for the same population — non-cirrhotic adults with MASH and moderate-to-advanced fibrosis — on the basis of the ESSENCE Phase 3 trial (Sanyal 2025 NEJM^[4]). ESSENCE randomized 1,197 adults with biopsy-confirmed MASH and F2 or F3 fibrosis to semaglutide 2.4 mg weekly or placebo with paired liver biopsies at week 72. MASH resolution without worsening of fibrosis was 62.9% on semaglutide vs 34.3% on placebo. Fibrosis improvement by at least one stage without worsening of MASH was 36.8% vs 22.4%. Wegovy is currently the only drug FDA-approved for both chronic weight management, cardiovascular event reduction (SELECT trial, Lincoff 2023^[10]), and MASH simultaneously.

The earlier Phase 2 semaglutide MASH trial (Newsome 2021 NEJM^[7]) was the prequel that justified building ESSENCE. It tested 0.1, 0.2, and 0.4 mg daily semaglutide in 320 adults and showed MASH resolution rates of 40%, 36%, and 59% vs 17% placebo, but did not show a statistically significant improvement in fibrosis at 72 weeks. ESSENCE used the higher 2.4 mg weekly Wegovy dose and the longer follow-up needed to clear the fibrosis-improvement endpoint.

Tirzepatide (Zepbound). The SYNERGY-NASH Phase 2 trial (Loomba 2024 NEJM^[5]) is positive but Zepbound is not yet FDA-approved for MASH. SYNERGY-NASH randomized 190 adults with biopsy-confirmed MASH and F2-F3 fibrosis to tirzepatide 5, 10, or 15 mg weekly or placebo for 52 weeks. MASH resolution without worsening of fibrosis was 51.8% (5 mg), 62.8% (10 mg), 73.3% (15 mg), and 13.2% (placebo). A Phase 3 program is ongoing. If your insurance denies Wegovy and you are eligible for Zepbound for weight management, that is a reasonable conversation to have with your hepatologist, but the formal MASH indication is not on the Zepbound label as of May 2026.

Step 4: who actually gets prescribed which drug

The hepatology decision is driven by fibrosis stage, the patient’s weight, comorbidities, and insurance:

• F0 to F1 with steatosis only (MASLD, not MASH): Neither Rezdiffra nor Wegovy is approved at this stage. AASLD guidance^[2] calls for lifestyle intervention first — Mediterranean diet, ≥7-10% body weight loss target, ≥150-200 min/week of moderate-intensity exercise, and alcohol minimization. If the patient also has obesity (BMI ≥30 or ≥27 with a comorbidity), Wegovy or Zepbound can be prescribed for weight management on the obesity indication, and the liver-fat improvement is a downstream benefit documented in STEP-1^[8] and SURMOUNT-1^[9] sub-analyses even though the FDA MASH indication does not formally apply at F0-F1.
• F2 to F3 MASH (the ESSENCE / MAESTRO-NASH population): Both Rezdiffra and Wegovy are on-label. Patients with obesity and cardiovascular comorbidities typically get Wegovy because of the simultaneous weight, CV, and liver benefit. Patients without obesity (BMI <27) or with a contraindication to GLP-1 therapy typically get Rezdiffra. Some patients will end up on both.
• F4 cirrhosis: Both Rezdiffra and Wegovy MASH approvals exclude decompensated cirrhosis. Patients with cirrhosis are managed by hepatology with portal hypertension surveillance, hepatocellular carcinoma screening, and transplant evaluation if appropriate.

Step 5: lab and imaging monitoring you should expect

Whether you start Wegovy, Rezdiffra, or both, the monitoring cadence is similar:

• Baseline labs: AST, ALT, alkaline phosphatase, GGT, bilirubin, albumin, INR, platelet count, lipid panel, HbA1c, fasting glucose, TSH. The AST/ALT ratio and FIB-4 calculation give a baseline non-invasive fibrosis estimate.
• Baseline imaging: FibroScan for liver stiffness (kPa) and controlled attenuation parameter (CAP) in dB/m for steatosis. MRI-PDFF if FibroScan is discordant or unavailable.
• Monitoring during treatment: AST and ALT every 3 months for the first year. FibroScan or MRI-PDFF at 6-12 month intervals. Significant ALT reduction (typically ≥17 U/L from baseline at 6 months) is an early signal of MASH response on either drug class.
• Re-staging: Most hepatologists re-evaluate fibrosis stage at 12-24 months on therapy. A repeat biopsy is uncommon outside of trial enrollment; serial FibroScan plus MRI-PDFF is the standard non-invasive re-staging package.

Step 6: insurance reality in 2026

The August 2025 Wegovy MASH approval changed the insurance landscape meaningfully. Patients with documented MASH and F2-F3 fibrosis now have a label-based justification that did not exist when Wegovy was only approved for chronic weight management. Practical points to bring to your hepatologist:

• A diagnostic code for MASH (K75.81 or K76.0 with appropriate modifiers) plus a fibrosis stage documented by FibroScan, MRI-PDFF, or biopsy is now the standard prior-authorization packet.
• Rezdiffra has a separate prior-authorization workflow because it is a specialty medication carrying a similar fibrosis-staging requirement.
• Medicare and many commercial plans treat the MASH indication differently from the obesity-only indication. A patient who was denied Wegovy for obesity in 2024 may be approved in 2026 on the MASH indication.
• State Medicaid coverage of GLP-1s remains a moving target. See our state Medicaid GLP-1 coverage tracker for the current status by state.

Step 7: lifestyle adjuncts are non-negotiable

Both Wegovy and Rezdiffra were tested on a background of lifestyle counseling. The AASLD 2023 Practice Guidance^[2] recommends:

• Mediterranean dietary pattern — vegetables, legumes, fish, olive oil, nuts, whole grains, limited red meat and refined sugar.
• Weight loss target ≥7-10% of body weight — the dose-response from older lifestyle-trial data (Vilar-Gomez and others) is the basis for this threshold; ≥5% reduces steatosis, ≥7% improves steatohepatitis, ≥10% improves fibrosis.
• Structured exercise ≥150-200 min/week of moderate-intensity activity, with the resistance-training component increasingly emphasized for lean-mass preservation on GLP-1 therapy — see our exercise pairing article.
• Alcohol minimization or abstinence. At fibrosis stage ≥F2 the AASLD guidance recommends abstinence. Alcohol is independently hepatotoxic and the combined risk with MASH is multiplicative, not additive.
• Coffee. Coffee intake (≥3 cups/day) is associated with reduced fibrosis progression in observational data and is not discouraged in the AASLD guidance.
• Vitamin E. 800 IU/day has historical evidence in non-diabetic MASH and is sometimes used, but the shift toward GLP-1 and resmetirom pharmacotherapy has reduced its role for most patients.

Step 8: how the magnitudes compare

The numbers look very different across the three trials — but the cross-trial comparison is not statistically valid. The placebo arm in ESSENCE was substantially higher than in MAESTRO-NASH (34.3% vs 9.7%), in part because ESSENCE used paired biopsies at 72 weeks vs 52 in MAESTRO-NASH and in part because the patient populations were not identical. The head-to-head comparisons that would settle the Wegovy-vs-Rezdiffra question are not yet published. The evidence-supported takeaway is that all three drugs have statistically significant MASH-resolution effects vs placebo in their own trials, and the choice in clinic depends on comorbidities and access, not on cross-trial magnitude.

Your action plan

1. Get formally staged. If you have only imaging-based steatosis (a radiology read of “hepatic steatosis” on ultrasound or CT), ask for FIB-4 and FibroScan. MRI-PDFF if available. This determines whether you are F0-F1 (lifestyle), F2-F3 (drug-eligible), or F4 (specialist management).
2. Bring the cardiometabolic risk-factor list — BMI, prediabetes or T2D, blood pressure, lipid panel, waist circumference. The MASLD definition requires at least one of these alongside steatosis.
3. Discuss Wegovy vs Rezdiffra vs both with the hepatologist. Patients with obesity and CV risk typically get Wegovy first. Patients without obesity typically get Rezdiffra. Some patients on Wegovy for weight loss who have residual MASH on re-staging will add Rezdiffra.
4. Plan the lifestyle work that runs in parallel. Mediterranean diet, ≥150 min/week activity, alcohol minimization or abstinence, 7-day food log for the first baseline visit. The drug is not the whole intervention.
5. Confirm prior-authorization pathway. A documented fibrosis stage plus the MASH ICD-10 code is the standard prior-auth packet for the MASH indication on Wegovy and for Rezdiffra.
6. Schedule the monitoring. AST/ALT every 3 months for the first year; FibroScan at 6-12 months; re-stage at 12-24 months.

Related research

• Wegovy for MASH, MAFLD & Fatty Liver: FDA Approval & ESSENCE Evidence Review — the deep evidence walkthrough of ESSENCE, the SYNERGY-NASH comparison, and the 2025 supplemental approval.
• Top GLP-1 MASH and MASLD studies — the Top-N PubMed list of all major MASH trials of GLP-1 and incretin therapies.
• Does GLP-1 cause liver damage? NAFLD and MASH evidence — the safety side of the question, including the rare DILI postmarketing signal.
• Retatrutide for MASH and MASLD — the investigational triple agonist Phase 2a substudy for context.
• Exercise pairing on a GLP-1 — the resistance-training half of the lifestyle adjuncts.
• Semaglutide drug page and tirzepatide drug page — the dose ladders, side effects, and pricing context.

Important disclaimer. This article is educational and does not constitute medical advice. Fatty liver disease ranges from asymptomatic MASLD to decompensated cirrhosis with portal hypertension; the workup, drug choice, and surveillance plan must be tailored by the hepatologist or primary clinician managing the patient. Patients with cirrhosis (F4) are outside the FDA-approved MASH indications for both Wegovy and Rezdiffra and require dedicated specialist management. PMIDs were independently verified against the PubMed E-utilities API on 2026-05-28. The Wegovy label was consulted via the DailyMed mirror of the FDA-approved prescribing information.

Last verified: 2026-05-28. Next review: every 6 months, or sooner if Zepbound receives a MASH indication or a head-to-head Wegovy-vs-Rezdiffra trial reports.