By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
Mounjaro for fatty liver: why it matters to so many people
Mounjaro for fatty liver is a topic on the minds of many doctors and patients today. Fatty liver is the most common liver disease in the world, and it is directly linked to obesity, diabetes and heart disease. Three new real-world studies looked at what happens to people with fatty liver who take Mounjaro. The findings point to fewer liver complications, fewer heart events and lower mortality, along with better blood test results after just 12 weeks.
What is metabolic fatty liver?
Its current medical name is MASLD, metabolic dysfunction-associated steatotic liver disease. In this disease, fat builds up in liver cells, usually on a background of excess weight, insulin resistance or diabetes. In some patients, the fat triggers inflammation, which doctors call MASH. Over the years, this inflammation can lead to liver scarring (fibrosis), cirrhosis and even liver cancer. In addition, people with fatty liver face a higher risk of heart disease, so treatment needs to address the whole body. I explain the right workup in my guide to diagnosing and treating fatty liver.
Mounjaro in brief
Mounjaro is a weekly injection containing tirzepatide. Specifically, the drug acts on two gut hormones, GLP-1 and GIP; it improves blood sugar control and reduces appetite. A controlled trial called SYNERGY-NASH studied patients with fatty liver inflammation and moderate or advanced scarring. After 52 weeks, the inflammation resolved without worsening of scarring in 62% of patients on the 15 mg dose, compared with 10% on placebo. However, a controlled trial studies a selected group. That is why it is important to see what happens in the real world as well. For a full overview of the drug, see my complete guide to Mounjaro.
Study one: Mounjaro for fatty liver versus SGLT2 inhibitors
The first study, published in Hepatology International, compared Mounjaro with drugs from the SGLT2 inhibitor family. Notably, these are diabetes drugs that also protect the heart and kidneys, such as Jardiance and Forxiga. The researchers used the TriNetX database, which pools medical records from many centers around the world.
The study included adults with metabolic fatty liver who started one of the drugs between January 2022 and June 2025. After statistical matching of the groups, each group included 23,106 patients. The researchers looked at a combined measure of death from any cause, major adverse cardiovascular events (MACE) and major adverse liver outcomes (MALO).
The results
Compared with SGLT2 inhibitors, Mounjaro was associated with a 28% lower risk on the combined measure (HR 0.72). Each component on its own also showed a lower risk:
- Death from any cause: HR 0.55, or a 45% lower risk.
- Major cardiovascular events: HR 0.68, a 32% lower risk.
- Major liver complications: HR 0.66, a 34% lower risk.
For clarity, the HR, or hazard ratio, compares the rate of events between two groups. A value of 1 means equal risk, while a value below 1 points to a lower risk in the treatment group. The results held up across subgroups by age, sex, BMI and underlying conditions.
Study two: low-dose Mounjaro for fatty liver
The second study, published in the Journal of Diabetes and its Complications, took place in Greece. It was a prospective study, meaning the researchers followed patients forward over time from the start. It included 75 adults with obesity and without diabetes, with an average age of 46.9 years. Patients received low-dose Mounjaro: 2.5 mg a week, then 5 mg a week, for 12 weeks.
As a result, after just 12 weeks, weight fell by an average of 8.1%. In addition, the researchers found significant drops in total cholesterol, LDL cholesterol, triglycerides, fasting blood sugar and HbA1c. The liver fat index, HSI, also fell significantly. On the other hand, there was no effect on the “good” cholesterol, HDL.
What is HSI?
HSI, or Hepatic Steatosis Index, is a score calculated from liver enzyme blood tests, BMI, sex and the presence of diabetes. It estimates the likelihood of fatty liver, but it does not replace an imaging test. In other words, the study showed improvement in a calculated score; it did not examine the liver by ultrasound or biopsy.
An interesting finding: it is not just about weight
The improvement in blood lipids occurred independently of weight loss. By contrast, the improvement in HbA1c and HSI was tied to how much weight patients lost. Moreover, the improvement stood out in people who started with abnormal values, and statin use did not affect the results. I covered the effect on blood lipids in detail in my guide to Mounjaro and high blood lipids.
Study three: Mounjaro for fatty liver versus bariatric surgery
The third study, also from Hepatology International, compared Mounjaro with bariatric-metabolic surgery. It included adults with metabolic fatty liver and obesity, again from the TriNetX database. Again, after statistical matching, each group included 6,199 patients.
Here are the results, per 100 patient-years of follow-up:
- Combined measure of death, heart events, kidney events and liver complications: 1.9 with Mounjaro versus 3.5 after surgery (HR 0.47).
- Death from any cause: 0.4 versus 0.9 (HR 0.36).
- Major adverse kidney events (MAKE): 0.7 versus 1.8 (HR 0.32).
- Major adverse liver outcomes (MALO): 0.8 versus 2.0 (HR 0.32).
How to read this finding
As a bariatric surgeon, I read this finding with great interest and great caution. First, this is a retrospective study, not a trial in which patients were randomly assigned. Second, patients who choose surgery often differ from those who choose medication, in ways that statistical matching does not always balance. Third, the study abstract does not specify the length of follow-up, and two letters to the editor appeared after it came out. So the study raises an important question, but it does not prove that a drug beats surgery. In practice, the choice between the two is personal, and sometimes combining them is the best solution. I wrote about this in my article “What I achieved with a scalpel, they achieve with an injection.”
Mounjaro for fatty liver: the limits of real-world studies
In general, real-world studies show an association, not necessarily cause and effect. Even after statistical matching, unmeasured differences between the groups may remain. In addition, medical record databases depend on the quality of the records. Similarly, the Greek study was small, short and had no control group. That is why the researchers behind the first study call for prospective trials to confirm the findings. Still, when several studies using different methods point in the same direction, the picture grows stronger.
Mounjaro for fatty liver: what it means for you
If you have been diagnosed with fatty liver, the first step is to assess your level of risk. Simple blood tests and the FIB-4 score help identify who needs further testing, such as a FibroScan. Likewise, weight loss remains the cornerstone of treatment, by whatever path suits you. In my clinic, I build this workup into a structured protocol, which I described in my article on metabolic fatty liver in the clinic. If you also live with diabetes, my guide to obesity and type 2 diabetes may help.
A few practical steps:
- Ask your doctor to calculate your FIB-4 score from your blood tests.
- Cut back on sugar, sweetened drinks and alcohol, which burden the liver.
- Get regular physical activity, even without major weight loss.
- If you also have obesity or diabetes, ask whether medication is right for you.
The bottom line
Three real-world studies support the benefit of Mounjaro for fatty liver. Compared with SGLT2 inhibitors, it was linked to fewer liver complications, fewer heart events and lower mortality. At a low dose, it also improved blood test results after just 12 weeks. The comparison with bariatric surgery is intriguing, but it needs confirmation in controlled trials. Ultimately, treating fatty liver means treating the whole body, and we tailor it to each patient.
The information in this article is general only and is not a substitute for personalized medical advice. Consult your doctor before starting or changing any treatment.
References
Tirzepatide for Metabolic Dysfunction-Associated Steatohepatitis with Liver Fibrosis
The researchers in the bariatric surgery comparison study stated that they received no funding and have no conflicts of interest. The SYNERGY-NASH trial was funded by Eli Lilly.
