Retatrutide results show weight and liver-fat losses.
Phase 2, early tests of benefit, measured weight, liver fat, and type 2 diabetes. Learn what changed with retatrutide and what remains unknown.
Retatrutide results cannot yet establish lasting safety
As a possible weight and sugar treatment, retatrutide still has tests to complete. Here you'll read the measured changes and the limits of each finding. Phase 2 means early tests of benefit, rather than proof of lasting safety. Studies followed selected adults. Weight fell 24.2% on average at the highest amount over 48 weeks. In the liver study, 86% reached normal liver fat by week 24. In type 2 diabetes, the sugar blood-test reading fell by over 2 points on its percentage scale.
That fall is subtracted from the starting test reading. Without a starting reading, you can't work out a full before-and-after result.
Phase 3, larger tests before an approval request, was still running as of 2026. Published Phase 2 findings are early benefit checks. Phase 3 must check more people over longer use. Your lasting health needs those later answers.
The Phase 2 early weight test found losses over months
The 2023 study lasted 48 weeks and followed 338 adults [1]. Volunteers had either obesity or another illness alongside excess weight. BMI relates a person's weight to their height. A BMI of 30 falls in the obesity range; 27 falls in the overweight range. Those figures aren't weights in pounds.
| Treatment given in the study | Weight change after 48 weeks |
|---|---|
| Placebo, a shot without retatrutide | −2.1% |
| 1 milligram | Loss grew with the amount |
| 4 milligrams | Loss grew with the amount |
| 8 milligrams | Loss grew with the amount |
| 12 milligrams | −24.2% |
The percentages measure starting weight lost, without promising your results.
Stomach trouble was more frequent with greater amounts, including vomiting, constipation, diarrhea, and nausea. Most complaints were mild or moderate. At 12 milligrams, 18% stopped, mainly because of stomach trouble. Pulse rose most around 24 weeks.
The 12 milligrams result was the largest average loss published from a Phase 2 test, an early benefit study. Phase 3, larger later tests, must settle more of the safety questions.
Liver scans improved without proving that scars healed
Only 98 people joined the 2024 liver study, which lasted 48 weeks [5]. All carried excess weight, with at least 10% fat in their livers. None had diabetes. That limits how closely their findings may match your health.
The changes below compare liver fat at the start with liver fat after 24 weeks. They aren't the share of the whole liver that disappeared.
| Treatment in the study | Change in starting liver fat after 24 weeks | Reached normal liver fat, below 5% |
|---|---|---|
| Placebo, a drug-free shot | +0.3% | — |
| 1 milligram | −42.9% | — |
| 4 milligrams | −57.0% | — |
| 8 milligrams | −81.4% | — |
| 12 milligrams | −82.4% | 86% |
At 48 weeks, liver fat was down −86.0% with 12 milligrams. A blood test linked to liver injury also improved.
The surprising limit is that even this large fall in fat doesn't prove liver scars healed.
The fall may involve glucagon helping stored liver fat become fuel [7]. GLP-1, the hunger hormone copied by some other drugs, mainly reduces liver fat through eating less and losing weight. Retatrutide adds an effect on fuel use. Your liver's lasting health still needs checking.
A 2026 review of drugs copying glucagon, including retatrutide, found improved scans compared with placebo [12]. Tests linked to liver injury and scarring also improved. These tests aren't direct proof that damaged liver tissue healed.
Type 2 diabetes improved in the Phase 2 early benefit test
The 2023 study followed 281 adults with type 2 diabetes for 36 weeks [2]. That can't settle years of safety.
- Sugar test after 24 weeks: The blood test reflecting sugar levels over recent months improved with 12 milligrams. Placebo, a drug-free shot, brought almost no change. Starting and ending readings aren't given.
- Weight after 36 weeks: −16.94% with 12 milligrams, against −3.00% with placebo. These percentages concern starting weight.
- Stomach trouble: Mild or moderate in 35%.
- Severe low sugar and deaths: None recorded.
People taking insulin needed less insulin to avoid low sugar. GLP-1/GIP, the hormone effects copied by retatrutide, increase insulin release. Your insulin shots can add to that effect, so the study's medical checks mattered.
Separate studies cannot select the right drug for your health
These drugs were studied in different people over different lengths of time. You can't treat that as a fair drug test. Moiz and colleagues' 2025 review covered 26 studies and 15,491 adults without diabetes [9]. Retatrutide at 12 milligrams showed 22.1% weight loss over 48 weeks. The review used a 95% range around that average. Ranges made this way would cover the true average ninety-five times in a hundred if similar studies were repeated. That concerns the estimated average, not each person's loss. Tirzepatide at 15 milligrams showed 17.8% over 72 weeks. Semaglutide at 2.4 milligrams showed 13.9% over 68 weeks. The differences ruled out one fair average.
Abulehia and colleagues' 2026 review estimated the greatest weight and sugar falls with retatrutide [14]. Only the sugar change was clear enough to make chance an unlikely cause. Weight did fall, but the weight estimate was less certain. Survodutide, another drug under study, ranked next for those estimated changes.
Katsi and colleagues' 2025 review described losses up to about 24% as a large advance [6]. Phase 1/2 means the early safety tests and early tests of benefit. That finding can't settle your treatment choice.
You can read how retatrutide acts or examine the retatrutide studies to understand the remaining limits.