Two drugs are FDA-approved for noncirrhotic MASH with F2–F3 fibrosis: resmetirom (Rezdiffra), a liver-targeted thyroid-hormone-receptor-β agonist and the first approval (March 2024); and semaglutide 2.4 mg (August 2025), a GLP-1 metabolic drug. Others — survodutide, FGF21 analogues, and lanifibranor — remain investigational. Both approved drugs treat, but do not "cure," MASH.
Section accent: --clay (MASLD pillar).
[verify] on update.What "MASH drug" means (and who these are for)
A MASH medication is not a fatty-liver drug for everyone. The approved agents target a specific group: adults with noncirrhotic MASH and F2–F3 fibrosis — moderate-to-advanced scarring, but not yet cirrhosis. That targeting exists because:
- Simple steatosis (fat without significant inflammation or fibrosis) usually doesn't need drug therapy — metabolic and lifestyle care is the foundation.
- Cirrhosis (F4) is a different, later problem the current approvals don't cover.
- Fibrosis stage — not fat amount — is what these drugs are trying to change, because fibrosis is what drives outcomes.
This is why you can't know whether a MASH drug applies to you without fibrosis staging (FIB-4 → elastography, sometimes biopsy). → FIB-4 · FibroScan & Elastography · Liver Biopsy
Resmetirom (Rezdiffra) — the first approval
| Field | Detail |
|---|---|
| Class / mechanism | Liver-directed thyroid hormone receptor-β (THR-β) agonist; stimulates hepatic pathways that reduce liver fat and improve metabolism |
| Indication | First FDA-approved MASH drug (March 2024) — noncirrhotic MASH with F2–F3 fibrosis, with lifestyle change; European Commission–approved (Aug 2025) |
| Fibrosis stage | F2–F3 (not cirrhosis) |
| Efficacy | In MAESTRO-NASH (52-week histology), at the approved 80 mg/100 mg doses: MASH resolution 25.9%/29.9% vs 9.7% placebo and ≥1-stage fibrosis improvement 24.2%/25.9% vs 14.2% placebo (p<0.001); accelerated approval on surrogate endpoints |
| Safety | Mainly gastrointestinal (diarrhea, nausea) early on; label includes attention to lipids, potential eye and drug-interaction considerations |
| Monitoring | Per label — liver-related and other labs, and interaction awareness; ongoing fibrosis assessment |
| Limits | Accelerated approval; long-term outcome data maturing; not for cirrhosis or simple steatosis; taken alongside — not instead of — metabolic/lifestyle care |
Resmetirom's significance is historic: it is the first drug ever approved specifically for MASH, and it validated fibrosis-stage-targeted therapy. It is liver-directed, so unlike the metabolic drugs it isn't primarily a weight or glucose treatment. → Fatty Liver & Weight Loss
Semaglutide 2.4 mg — the metabolic route, now approved
| Field | Detail |
|---|---|
| Class / mechanism | GLP-1 receptor agonist; weight loss + improved insulin sensitivity/glucose control drive most of the liver benefit |
| Indication | FDA-approved for noncirrhotic MASH with F2–F3 fibrosis (accelerated approval, August 2025) — the first GLP-1 with a MASH indication |
| Fibrosis stage | F2–F3 (not cirrhosis) |
| Efficacy | In ESSENCE (72-week histology), MASH resolution 62.9% vs 34.3% placebo and ≥1-stage fibrosis improvement 36.8% vs 22.4% placebo (both p<0.001, both endpoints met); the fibrosis benefit is smaller in absolute terms but statistically significant |
| Safety | Mainly gastrointestinal (nausea, vomiting, diarrhea); boxed warning for medullary thyroid carcinoma/MEN2; pancreatitis caution; avoid in pregnancy; perioperative hold |
| Monitoring | Metabolic/weight response; standard GLP-1 cautions; ongoing fibrosis assessment |
| Limits | Accelerated approval; fibrosis effect more modest than inflammation effect; weight (and liver fat) tend to return if stopped |
Because semaglutide's liver effect is largely mediated by weight and metabolic improvement, it does double duty — treating MASH while also addressing the obesity, diabetes, and cardiovascular risk that usually accompany it. That whole-patient reach is a genuine advantage. → GLP-1 & Fatty Liver · MASLD & Cardiovascular Risk
Resmetirom vs semaglutide — how to think about the choice
They are not interchangeable and are sometimes complementary:
- Resmetirom is liver-directed — chosen primarily to treat the MASH/fibrosis itself, including in people who don't need or can't take a weight-loss drug.
- Semaglutide is metabolic — attractive when obesity, type 2 diabetes, or high cardiovascular risk sit alongside the MASH, because one drug addresses several drivers.
- Both are accelerated approvals for the same F2–F3 window, both are added to lifestyle change, and neither is a cure.
The decision is individualized to the whole metabolic picture — exactly the kind of "what does this mean for this patient?" reasoning behind our program. → The San Diego Metabolic-Liver Program
The pipeline — investigational, not approved
These agents are in development and not FDA-approved for MASH. They should never be presented as available treatments:
- Survodutide — GLP-1/glucagon dual agonist; investigational for MASH. Grade D 🔴 (investigational)
- FGF21 analogues (e.g., efimosfermin, pegozafermin) — target hepatic metabolism/fibrosis pathways; investigational. Grade D 🔴
- Lanifibranor — pan-PPAR agonist; investigational for MASH. Grade D 🔴
- Others across incretin, FGF21, and metabolic classes are in trials.
The trajectory is real — a field that had zero approved drugs before 2024 now has two and a deep pipeline — but "in trials" is not "available," and effect sizes and safety for these agents are still being established. → The Next Generation of Obesity Drugs (/treat/future)
What none of these drugs do
- They don't replace sustained weight loss and metabolic care, which remain foundational. → Fatty Liver & Weight Loss
- They aren't for simple steatosis or cirrhosis — the approvals target F2–F3 MASH.
- They don't remove the need for fibrosis staging and monitoring — you need to know your stage to know if a drug applies, and to track response.
- They don't "cure" MASH — they improve inflammation and, more modestly, fibrosis, on accelerated approvals with outcome data still maturing.
MASLD MYTHS — MASH Medications
MYTH: "There's still no real medicine for fatty liver disease." - Short answer: Outdated — two drugs are now FDA-approved for MASH with fibrosis. - What the evidence shows: Resmetirom (2024) and semaglutide (2025) are approved for noncirrhotic F2–F3 MASH. - Bottom line: Approved options exist, for the right group. - Grade A 🟢
MYTH: "Resmetirom is a weight-loss drug." - Short answer: No — it's a liver-directed THR-β agonist. - What the evidence shows: It targets hepatic metabolism to improve MASH and fibrosis, not primarily body weight. - Bottom line: It treats the liver directly; semaglutide is the metabolic/weight route. - Grade A 🟢
MYTH: "If a MASH drug is approved, I can skip diet and exercise." - Short answer: No — both approvals are added to lifestyle change. - What the evidence shows: Sustained weight loss and metabolic care remain foundational; drugs supplement them. - Bottom line: Medication plus lifestyle, not instead of. - Grade A 🟢 → Nutrition for MASLD
MYTH: "Survodutide and lanifibranor are available treatments." - Short answer: They're investigational, not approved. - What the evidence shows: These pipeline agents are in trials; effect sizes and safety are still being established. - Bottom line: "In trials" is not "available." - Grade D 🔴
MYTH: "A MASH drug will reverse my cirrhosis." - Short answer: The approvals are for F2–F3, not cirrhosis (F4). - What the evidence shows: These drugs target noncirrhotic MASH; cirrhosis is a different, later stage they aren't approved to treat. - Bottom line: Know your fibrosis stage before assuming a drug applies. → FIB-4 - Grade A 🟢
SIGNATURE — "What the evidence says: MASH drugs"
- What we know: Two drugs are FDA-approved for noncirrhotic F2–F3 MASH — resmetirom (liver-directed THR-β) and semaglutide (metabolic GLP-1) — both improving MASH resolution and fibrosis versus placebo, with the fibrosis benefit smaller in absolute terms but statistically significant.
- What we think: Choice depends on the whole metabolic picture; combination and sequential strategies will likely be studied, and the pipeline will expand options.
- What we don't know: Long-term hard-outcome data, comparative effectiveness, durability, and the eventual role of pipeline agents (survodutide, FGF21s, lanifibranor).
- What patients should do: Get staged (FIB-4 → elastography), treat the metabolic disease, and discuss a drug only if you're in the F2–F3 MASH group.
Questions patients ask
What medications are approved for MASH?
Two: resmetirom (Rezdiffra), approved March 2024, and semaglutide 2.4 mg, approved August 2025 — both for noncirrhotic MASH with F2–F3 fibrosis. Grade A 🟢
What is resmetirom (Rezdiffra) and how does it work?
It's a liver-directed thyroid-hormone-receptor-β agonist that improves liver fat, MASH, and fibrosis — the first drug approved specifically for MASH. Grade A 🟢
How is resmetirom different from semaglutide for MASH?
Resmetirom is liver-directed; semaglutide is a metabolic/weight drug whose liver benefit comes largely through weight loss. Different mechanisms, same F2–F3 indication. Grade A 🟢 → GLP-1 & Fatty Liver
Who qualifies for a MASH drug?
Adults with noncirrhotic MASH and F2–F3 fibrosis — which requires fibrosis staging (FIB-4, elastography, sometimes biopsy) to establish. Grade A 🟢 → FIB-4
Can I take a MASH drug if I have simple fatty liver?
No — simple steatosis without significant fibrosis isn't the approved indication; the foundation there is metabolic and lifestyle care. Grade A 🟢
Are there side effects?
Resmetirom is mainly gastrointestinal with lipid/eye/interaction considerations per label; semaglutide is mainly gastrointestinal with GLP-1 class cautions (thyroid boxed warning, pancreatitis, pregnancy). Grade A 🟢
Do I still need to lose weight if I'm on a MASH drug?
Yes — both are added to sustained lifestyle change, which remains foundational for the liver and for cardiovascular health. Grade A 🟢 → Fatty Liver & Weight Loss
What about survodutide, pegozafermin, or lanifibranor?
All investigational — in trials, not FDA-approved. They shouldn't be treated as available options. Grade D 🔴 → /treat/future
Will these drugs cure MASH?
No — they improve inflammation and, more modestly, fibrosis, on accelerated approvals with long-term outcome data still maturing. Grade A 🟢 / B 🟡
How do I choose between the two approved drugs?
It's individualized — resmetirom when the aim is liver-directed therapy; semaglutide when obesity, diabetes, or high CV risk sit alongside the MASH. Grade B 🟡 → The San Diego Metabolic-Liver Program
KEEP READING
- GLP-1 & Fatty Liver — the semaglutide MASH approval in depth, and fat vs fibrosis endpoints.
- Fatty Liver & Weight Loss — the foundation every MASH drug is added to.
- FIB-4 and FibroScan & Elastography — how to find out if a MASH drug applies to you.
- The San Diego Metabolic-Liver Program — how the whole picture drives the choice.
Written by Darius A. Schneider, MD, PhD · Board-Certified Endocrinologist (ECNU) · Last updated: [date] · References: FDA labeling for resmetirom (Rezdiffra, March 2024) and semaglutide 2.4 mg (MASH, Aug 2025); ESSENCE program; AASLD Practice Guidance on MASLD (2023). Regulatory and pipeline status re-verified on update — see verify-status note. Educational only; not individualized advice.
