Research suggests it can, and the evidence here is stronger than for most of the "bonus" benefits people attach to these medications. In August 2025, the FDA granted accelerated approval to semaglutide 2.4 mg for a serious form of fatty liver disease, after a 72-week trial showed the liver inflammation cleared up in about 63% of people taking it.
That approval comes with fine print, though, and the fine print decides whether any of it applies to you.
The Quick Answer
GLP-1 medications may reduce liver fat and inflammation in people with fatty liver disease. In the phase 3 ESSENCE trial, 62.9% of people on semaglutide 2.4 mg saw their steatohepatitis resolve without fibrosis getting worse, compared with 34.3% on placebo.2 In the phase 2 SYNERGY-NASH trial, tirzepatide resolved it in 44% to 62% of participants depending on dose, versus 10% on placebo.4 The FDA approval covers branded semaglutide 2.4 mg for adults with MASH and moderate to advanced scarring (stage F2 to F3), not simple fatty liver and not cirrhosis.3
Fatty Liver, MASLD, MASH: the New Names
If your doctor once told you that you had "fatty liver" or NAFLD, the condition has been renamed. In 2023, the major liver societies switched to MASLD (metabolic dysfunction-associated steatotic liver disease) for fat buildup in the liver tied to things like excess weight, insulin resistance, high blood pressure, or high triglycerides. The more serious, inflamed version, formerly NASH, is now MASH (metabolic dysfunction-associated steatohepatitis).6
The distinction matters because the two behave very differently. Plain fat in the liver is common and often sits there quietly for years. MASH means the fat has started damaging liver cells, which sets off inflammation, and over time that inflammation can lay down scar tissue. Doctors grade the scarring from F0 (none) to F4 (cirrhosis), and the fibrosis stage is the thing most closely tied to long-term liver outcomes.
It's also far more common than most people assume. Using national health survey data from 2017 to 2023, researchers estimated that about 31.9% of U.S. adults have MASLD, and steatotic liver disease of any kind affects about 35% of U.S. adults.1 Most of them don't know it, since fatty liver rarely causes symptoms until it's advanced. It usually turns up by accident, on an ultrasound ordered for something else or a liver enzyme (ALT) that comes back a little high on routine bloodwork.
What the Semaglutide Trial Found
ESSENCE is the trial that led to the FDA approval. Researchers enrolled adults with biopsy-confirmed MASH and moderate to advanced scarring (F2 or F3), gave them weekly semaglutide 2.4 mg or placebo, and then biopsied their livers again at 72 weeks. The results below come from the first 800 participants.2
| Outcome at 72 weeks | Semaglutide 2.4 mg | Placebo |
|---|---|---|
| Steatohepatitis resolved, fibrosis no worse | 62.9% | 34.3% |
| Fibrosis improved, steatohepatitis no worse | 36.8% | 22.4% |
| Both outcomes together | about 33% | about 16% |
| Average body weight change | −10.5% |
Source: Sanyal et al., NEJM 2025.2
The placebo group did surprisingly well, with about a third seeing their inflammation resolve. That's typical in liver trials, partly because everyone gets counseling on diet and exercise and partly because biopsies can vary depending on which bit of tissue the needle happens to sample. Semaglutide still roughly doubled the placebo rate on every measure.
The fibrosis result is the more cautious one. Inflammation can calm down within months, but scar tissue remodels slowly, so a gap of 36.8% versus 22.4% at 72 weeks is meaningful without being dramatic. Part 2 of ESSENCE runs to 240 weeks and will look at whether people on semaglutide actually have fewer cirrhosis, transplant, and liver-related death events. Those results aren't expected until 2029.3
On tolerability, the side effects were the familiar ones (nausea, diarrhea, constipation).
What the Tirzepatide Trial Found
Tirzepatide's evidence comes from SYNERGY-NASH, a smaller phase 2 trial. It enrolled 190 adults with biopsy-confirmed MASH and F2 or F3 fibrosis and ran for 52 weeks.4
| Outcome at 52 weeks | Tirzepatide 5 mg | 10 mg | 15 mg | Placebo |
|---|---|---|---|---|
| MASH resolved, fibrosis no worse | 44% | 56% | 62% | 10% |
| Fibrosis improved ≥1 stage, MASH no worse | 55% | 51% | 51% | 30% |
| Average body weight change | −10.7% | −13.3% | −15.6% | −0.8% |
Source: Loomba et al., NEJM 2024, as summarized by the American College of Gastroenterology.4
Those resolution rates look excellent, and they are, but this was a phase 2 study, which means it was designed to find the right dose and check for a signal, not to settle the question. With only 190 people, the trial wasn't large enough to show a statistically solid fibrosis benefit, and the authors themselves noted that improving scar tissue probably takes longer than a year.4 Lilly is now running a larger outcomes trial called SYNERGY-Outcomes, testing tirzepatide and retatrutide in people with higher-risk fatty liver disease.
As of this writing, tirzepatide is not FDA-approved for MASH. And because the two trials ran for different lengths of time with different groups of people, you can't line up the 62% figures and declare a winner. If you're weighing the two medications more broadly, our tirzepatide vs semaglutide comparison covers the bigger picture.
How Much of This Is the Weight Loss?
A large share of it, probably. Weight loss has been the main recommendation for fatty liver for decades, and the reason is good data.
In a well-known 2015 study from Cuba, 293 adults with biopsy-confirmed NASH went through a year-long lifestyle program and then had a second biopsy. Overall, 25% saw their NASH resolve. Among the people who lost at least 10% of their body weight, though, 90% had their NASH resolve and 45% saw their fibrosis regress.5 The more weight people lost, the better their livers looked.
Now compare that with the drug trials, where average weight loss landed between about 10% and 16%. Researchers think GLP-1s may also act on liver fat and inflammation through pathways that don't depend entirely on the scale, including better insulin sensitivity, and the GIP side of tirzepatide may affect how fat tissue stores and releases fat. But nobody has cleanly separated the drug effect from the weight effect yet.
The practical problem with the lifestyle route is that only a minority of people reach that 10% mark through diet and exercise alone and keep it there. What a GLP-1 changes, for many people, is how reachable that number is. That also means the benefit likely depends on keeping the weight off. If you're curious what happens after stopping, we cover it in what happens when you stop a GLP-1.
What the FDA Approval Does and Doesn't Cover
The semaglutide approval is narrower than a lot of headlines made it sound. It applies to branded semaglutide 2.4 mg, used alongside a reduced-calorie diet and more physical activity, for adults with MASH and F2 to F3 fibrosis who don't have cirrhosis.3 It was an accelerated approval, which means the FDA approved it based on the biopsy results while it waits for the long-term outcome data from Part 2.
That leaves a few groups outside the label. If you have simple fatty liver with no inflammation or scarring, the approval doesn't apply to you, although losing weight is still the standard advice and a GLP-1 prescribed for weight management may support it. If you have cirrhosis (F4), neither semaglutide nor tirzepatide is approved for your liver, and that's a conversation for a hepatologist. And compounded semaglutide and tirzepatide weren't studied in these trials, so the approval itself doesn't extend to them.
Getting diagnosed with MASH and a specific fibrosis stage also isn't something a weight loss clinic does. It usually takes a gastroenterologist or hepatologist, along with blood-based scoring, a FibroScan (a type of ultrasound that measures liver stiffness), or a biopsy.
How We Approach It at Defiant
Our medical weight loss program in Lisle is a weight management program. We don't diagnose or stage liver disease, and we don't prescribe GLP-1s as a liver treatment. What we can do is make sure that if you already know you have fatty liver, or your labs hint at it, that information shapes your plan from day one.
Every Custom GLP-1 Protocol starts with a $50 consultation and a lab order you complete through your primary care doctor or Rythm Health. If your liver enzymes come back elevated, your provider will see it, and they'll tell you if it's worth talking to your doctor or a liver specialist before or alongside treatment. From there, your dose titrates every two weeks based on how you respond, with weekly nurse check-ins and a monthly Styku 3D body scan to confirm you're losing fat and not muscle. Programs start from $295/mo, and we see patients from Lisle, Naperville, Downers Grove, Wheaton, and across Chicago's western suburbs.
If you already have a liver specialist, bring their notes and your most recent imaging to your consult. Your hepatologist and your weight loss provider should be working from the same information.
- About 31.9% of U.S. adults have MASLD, the new name for fatty liver disease tied to metabolic health, and most don't know it.
- In the ESSENCE trial, 62.9% of people on semaglutide 2.4 mg saw their liver inflammation resolve without worsening fibrosis at 72 weeks, versus 34.3% on placebo.
- In the phase 2 SYNERGY-NASH trial, tirzepatide resolved MASH in 44% to 62% of participants at 52 weeks, versus 10% on placebo. Tirzepatide is not FDA-approved for MASH.
- The FDA approval covers branded semaglutide 2.4 mg for adults with MASH and F2 to F3 fibrosis, not simple fatty liver, not cirrhosis, and not compounded versions.
- Much of the liver benefit likely tracks with weight loss. In a lifestyle study, 90% of people who lost at least 10% of their weight saw their NASH resolve.
- Long-term data on whether GLP-1s prevent cirrhosis and liver failure isn't expected until 2029.
Frequently Asked Questions
A Healthier Liver Usually Starts With the Scale.
If you've been told your liver enzymes are high or you have fatty liver, weight loss is the most consistent recommendation in the research. A $50 consultation at Defiant in Lisle starts with your labs and history, then builds a Custom GLP-1 Protocol with bi-weekly titration and weekly check-ins around them.
Keep Reading
Last updated October 1, 2026.
References
- Kim D, Danpanichkul P, Wijarnpreecha K, et al. Current burden of steatotic liver disease and fibrosis among adults in the United States, 2017-2023. Clin Mol Hepatol. 2025;31(2):382-393. PubMed
- Sanyal AJ, Newsome PN, Kliers I, et al; ESSENCE Study Group. Phase 3 Trial of Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis. N Engl J Med. 2025;392(21):2089-2099. PubMed
- U.S. Food and Drug Administration. FDA approves treatment for serious liver disease known as MASH. August 2025. FDA
- Loomba R, Hartman ML, Lawitz EJ, et al; SYNERGY-NASH Investigators. Tirzepatide for Metabolic Dysfunction-Associated Steatohepatitis with Liver Fibrosis. N Engl J Med. 2024;391(4):299-310. PubMed
- Vilar-Gomez E, Martinez-Perez Y, Calzadilla-Bertot L, et al. Weight Loss Through Lifestyle Modification Significantly Reduces Features of Nonalcoholic Steatohepatitis. Gastroenterology. 2015;149(2):367-378. PubMed
- American Association for the Study of Liver Diseases. New MASLD Nomenclature. 2023. AASLD