Japan had no approved drug for fatty-liver disease until Friday. Now it has one, and it is a weight-loss shot.
On June 19 the Ministry of Health, Labour and Welfare cleared Wegovy, the 2.4 mg dose of semaglutide, for metabolic dysfunction-associated steatohepatitis (MASH) in adults with moderate to advanced liver scarring who do not yet have cirrhosis. Novo Nordisk Pharma and Sumitomo Pharma ↗, which co-promote the drug in Japan, said it is the first treatment any Japanese regulator has approved for the disease. Until now the standard of care was diet and exercise.
MASH is what happens when fat collects in the liver, inflames it, and lays down scar tissue (the scarring is called fibrosis). Left alone it can progress to cirrhosis, liver failure, and liver cancer. It is common, usually silent, and tightly bound to obesity and type 2 diabetes, the same conditions semaglutide already treats. The molecule is the GLP-1 receptor agonist ↗ sold as Ozempic for diabetes and Wegovy for obesity. This is the same drug cleared for a third job.
What the trial showed
The approval rests on Part 1 of the Phase 3 ESSENCE trial, published in the New England Journal of Medicine ↗ last year. ESSENCE randomized adults with biopsy-confirmed MASH and stage F2 or F3 fibrosis to semaglutide 2.4 mg or placebo, two to one.
At 72 weeks, 62.9 percent of the semaglutide group had their steatohepatitis resolve with no worsening of fibrosis, against 34.3 percent on placebo. In plain terms, roughly two in three patients on the drug cleared the liver inflammation, compared with about one in three who got a dummy injection. On the harder endpoint, actually reversing scar tissue, 36.8 percent improved their fibrosis with no worsening of inflammation, versus 22.4 percent on placebo. Both gaps held up as statistically significant.
What the numbers do not say is worth holding onto too. The placebo arm was not idle. A third of those patients resolved their MASH on lifestyle change and the trial's built-in dietary support alone. Semaglutide roughly doubled that rate, which is a genuine effect, but MASH is a disease where many people improve without any drug, and Part 1 only ran to 72 weeks. Whether clearing inflammation on a biopsy slide turns into fewer cirrhosis diagnoses and fewer deaths is the question the five-year Part 2 is built to answer.
A second major market
The United States got there first. The Food and Drug Administration approved Wegovy for the same indication ↗ in 2025. Japan is now the second large market to sign off, and it did so without ever approving a MASH drug of any other kind first.
That is the part worth noticing. The only other medicine approved for MASH anywhere, Madrigal's resmetirom in the US, is a thyroid-hormone receptor agonist aimed straight at liver metabolism. Semaglutide works from the other end, mimicking a gut hormone and driving most of its liver benefit through weight loss and better glucose control. Japan skipped the liver-first drug entirely and made its first MASH approval a metabolic one.
For a peptide that started as a diabetes injection, this is the clearest case yet of a gut-hormone mimic being repurposed organ by organ. Semaglutide ↗ now carries diabetes, obesity, cardiovascular risk reduction, and liver disease on the same 2.4 mg label, and the receptor it hits, GLP-1R ↗, keeps turning up in tissues no one prescribed it for. The liver is the one with an approval stamp now, in two of the world's biggest drug markets.