The best-supported peptides for fatty liver are the GLP-1-based drugs. Semaglutide (Wegovy) is the only peptide FDA-approved for the condition, for adults with MASH and moderate to advanced scarring: in its phase 3 trial, steatohepatitis resolved in 62.9% of patients versus 34.3% on placebo.[1][2] Tirzepatide and survodutide look promising in trials but are not approved for liver disease, and “liver peptides” such as BPC-157 have no human evidence.[12]
Fatty liver is now called MASLD (metabolic dysfunction-associated steatotic liver disease). Its inflamed, scarring form is MASH (formerly NASH). For more on how these drugs work, see our GLP-1 basics hub.
Evidence at a glance
| Peptide or drug | Evidence level | What was shown | FDA status | Our profile |
|---|---|---|---|---|
| Weight loss through diet and exercise (standard care) | Human studies | 10%+ weight loss led to MASH resolution in 90%[10] | First-line care | — |
| Semaglutide 2.4 mg (Wegovy) | FDA-approved for this use | MASH resolved in 62.9% vs 34.3%; scarring improved in 36.8% vs 22.4%[1] | Accelerated approval for MASH, F2-F3, no cirrhosis (2025)[3] | Semaglutide |
| Resmetirom (Rezdiffra), not a peptide | FDA-approved for this use | MASH resolved in 25.9-29.9% vs 9.7%[4] | Accelerated approval (2024)[5] | — |
| Tirzepatide | Human RCTs (phase 2) | MASH resolved in 44-62% vs 10%[6] | Not approved for liver disease | Tirzepatide |
| Survodutide | Human RCTs (phase 2 and 3) | MASH improved in 43-62% vs 14%[7] | Investigational | Survodutide |
| Pemvidutide | Human RCTs (phase 2b) | MASH resolved in 52-58% vs 20% at 24 weeks; scarring not improved[9] | Investigational | Pemvidutide |
| Glutathione (oral) | Small human studies | Lower liver enzymes in 29 people, no control group[11] | Not approved for liver disease | Glutathione |
| BPC-157 | Animal or lab only | No human liver trials | Not approved; FDA cites limited safety data[12] | BPC-157 |
Trials used different doses, lengths and patient groups, so the numbers are not head-to-head comparisons.
Start with what works: weight loss and liver care
Weight loss is still the foundation of treatment. In a Cuban study of 293 adults with biopsy-proven MASH who tried diet and exercise for a year, those who lost at least 10% of their body weight had MASH resolution in 90% of cases and less scarring in 45%. Losing 5% or more also improved liver biopsies, though only 30% of participants reached that goal.[10]
Both approved MASH drugs are labeled for use alongside a reduced-calorie diet and more physical activity.[3][5] A hepatologist or primary care clinician will usually also check for diabetes, high cholesterol, alcohol use and the stage of scarring, often with a blood test score and an elastography scan before any biopsy.
Semaglutide: the only approved peptide for MASH
Semaglutide copies the gut hormone GLP-1. It lowers appetite and blood sugar, and most of its liver benefit is thought to come from weight loss and better metabolism.
The ESSENCE trial. This phase 3 trial enrolled 1,197 adults with biopsy-confirmed MASH and stage F2 or F3 fibrosis. At the week-72 interim analysis of the first 800 patients:[1]
- Steatohepatitis resolved without worse scarring in 62.9% on semaglutide 2.4 mg versus 34.3% on placebo.
- Scarring improved without worse inflammation in 36.8% versus 22.4%.
- Body weight fell 10.5% versus 2.0%.
- Gastrointestinal side effects, such as nausea, were more common on semaglutide.
FDA status. FDA granted Wegovy accelerated approval in August 2025 for adults with noncirrhotic MASH and stage F2 to F3 fibrosis.[2] Accelerated approval rests on biopsy results, so continued approval depends on the second part of ESSENCE confirming fewer liver failures, transplants and deaths. That part runs to 240 weeks.[2][3]
Resmetirom: the non-peptide comparator
Resmetirom (Rezdiffra) is a daily pill, not a peptide. It activates a thyroid hormone receptor in the liver, which reduces fat buildup. FDA approved it in March 2024 as the first MASH drug.[5]
In MAESTRO-NASH, MASH resolved in 25.9% (80 mg) and 29.9% (100 mg) of patients versus 9.7% on placebo, and scarring improved in 24.2% and 25.9% versus 14.2%. Diarrhea and nausea were more common than on placebo.[4]
The two drugs have not been compared directly, and their trials measured results at different times (72 weeks vs 52 weeks). Some people may end up on both; that is a decision for a liver specialist.
Promising but not approved: tirzepatide, survodutide and pemvidutide
Tirzepatide acts on both GIP and GLP-1 receptors. In the 190-person SYNERGY-NASH phase 2 trial, MASH resolved in 44%, 56% and 62% of people on 5, 10 and 15 mg versus 10% on placebo after 52 weeks. Scarring improved by at least one stage in 51% to 55% versus 30%.[6] Lilly is now testing tirzepatide and retatrutide in SYNERGY-Outcomes, a phase 3 trial of about 4,500 people at high risk of liver complications, running to 2030.[14]
Survodutide acts on GLP-1 and glucagon receptors; glucagon may act directly on liver fat. In a 293-person phase 2 trial, MASH improved in 43% to 62% versus 14% on placebo, but nausea (66%) and vomiting (41%) were common.[7] In the phase 3 SYNCHRONIZE-MASLD trial, 84.2% on survodutide had at least a 30% cut in liver fat versus 24.3% on placebo.[8] The LIVERAGE phase 3 biopsy trial is recruiting.[13] Compare it with tirzepatide in our survodutide vs tirzepatide guide.
Pemvidutide, another GLP-1 and glucagon dual agonist, met its MASH resolution goal at 24 weeks in the IMPACT trial (52% to 58% vs 20%) but did not improve scarring compared with placebo at that point.[9]
Unproven “liver peptides”
- Glutathione is a tripeptide antioxidant sold as a supplement and as IV drips. Its best-known liver study was a 29-person, uncontrolled pilot in which liver enzymes fell after 4 months of oral glutathione. Everyone had also just completed 3 months of lifestyle changes, so the effect can’t be separated out.[11]
- BPC-157 is often marketed for liver “repair,” but its data come from rodent studies. FDA says it has identified little or no safety information for the routes people use, notes possible immune reactions and impurity concerns, and does not know whether it would harm humans.[12]
Products sold as “research peptides” are not approved, and their purity and dose are not checked. Our guides on research-use-only peptides and counterfeit peptides explain the risks.
Side effects and who should be careful
GLP-1 drugs commonly cause nausea, diarrhea, vomiting and constipation, and they carry warnings about gallbladder problems, pancreatitis and thyroid C-cell tumors seen in rodents.[3] See our GLP-1 side effects guide and GLP-1 gallbladder guide for details.
Questions to bring to your clinician:
- What stage is my liver scarring, and has it been measured?
- Would weight loss alone be enough for my stage?
- Am I a candidate for semaglutide or resmetirom, and will insurance cover it?
- Should I join a clinical trial?
If weight is part of the picture, our GLP-1 diet guide covers eating patterns that support treatment.
