What trials found
Retatrutide: what the trials found.
Read the retatrutide results in plain words, including the risks and gaps. Each number names its study.
What retatrutide may do in trials
Human trials are testing retatrutide as a possible drug. Eli Lilly also calls it LY3437943; obesity and type 2 diabetes are the illnesses under study. Here you'll find trial results first, followed by the gaps. The FDA has not approved the drug.
Retatrutide imitates three hormones, which are chemical messengers your body already makes. The first is GLP-1, short for glucagon-like peptide-1; the gut sends it out once you've eaten, and it helps curb hunger and steady blood sugar. The second, GIP, also comes from the gut; after food it tells the pancreas to let out insulin. The third is glucagon, made in the pancreas, and it may raise how many calories your body burns.
Phase 2 trials are early human studies that ask whether the drug shows an effect, and larger Phase 3 trials then check that result in more people. In one 48-week Phase 2 trial, people on the highest dose saw their weight fall by 24.2% on average. People on a placebo, a dummy shot with no drug in it, lost 2.1% [1]. That finding drew notice, but it didn't make retatrutide a prescription drug.
The Phase 3 TRIUMPH trials have not finished; results are expected in 2026-2027, and the FDA could review them afterward. Reports from people using research products appear on the reports and risks page. Beside each number, you'll find the study that supplied it.
What does retatrutide do
Every one of those copied hormones has its own job. GLP-1 can curb hunger and make the stomach empty more slowly. After a meal, GIP prompts the release of insulin, which clears sugar from the blood. Glucagon can increase daily calorie burn and reduce liver fat.
These studies were small and short, so their averages can't tell you your result. In a 338-person Phase 2 study, people on the highest dose lost an average 24.2% of body weight over 48 weeks [1]. In another 281-person study of type 2 diabetes, HbA1c, which shows average blood sugar, fell by 2.02% by 24 weeks [2]. A study team watched those people closely.
In a fatty-liver study, the amount of liver fat fell by 82.4% by 24 weeks [5]. A urine test for kidney leakage fell about 37% in people with type 2 diabetes [7]. Those findings look hopeful, yet they do not settle long-term safety. They also leave you without an answer about what follows after stopping.
A 2025 review saw losses of up to about 24% as much greater than results with older drugs [6]. Reviews gather published work; they aren't new trials. For you, each study's finding matters more than a promised result.
Is retatrutide fda approved, and what happens before approval
No. Retatrutide isn't FDA-approved in 2026. It remains in Phase 3 trials, and most drugs being tested never reach the market. No one can promise approval or give you a sound approval date.
Phase 3 results must be finished and sent to the FDA before a review can begin. The TRIUMPH work covers obesity, type 2 diabetes, heart problems, kidney disease, and a test against tirzepatide. That Phase 3 work is still going on. A good Phase 2 result doesn't skip any of those steps.
Phase 2 trials weren't built to settle years of safety. They also can't show whether people keep the weight off after care ends. Those are Phase 3 questions. Older GLP-1-class drugs often show weight regain after people stop them, but retatrutide still needs its own answer.
What retatrutide changes, and what studies still can't tell us
Only a few trials and reviews are in print so far. A 2025 review pooled three trials with 878 people. On average, people given the drug lost 14.33% more of their weight than people given the dummy shot [8]. Health problems of every kind, counted together, were not clearly more common in the drug groups.
A 2024 review covered drugs with three hormone actions. It said losses of about 20-30% could be near results seen after weight-loss surgery [9]. That broad review isn't a promise about retatrutide. For a firmer answer, you need the larger trials.
In Phase 2, nausea and diarrhea led the list, followed by vomiting and constipation. Resting pulse at the highest doses rose about 5-7 beats per minute and reached its top level around week 24. The heart study hasn't reported, so years of risk remain unknown.
The research guide explains how the drug works. On the reports and risks page, personal accounts sit apart from trial evidence. Together they state the known facts and the remaining gaps.
Retatrutide availability and what isn't approved
No approved retatrutide prescription is available anywhere as of 2026. The drug is used only in trials where a study team watches each person. If you see a vial sold elsewhere under that name, its contents and cleanliness have not been proved.
Those research-labeled vials sit outside normal clinic and pharmacy checks. No sales or seller links appear here. The Retatrutide references page lists the studies used on this site.