Retatrutide Results: What Happened to People in the Studies
Phase 1b was an early small test; Phase 2a began the next stage. Here are the changes in weight, sugar, liver fat, and heart rate.
What the retatrutide results can tell you
What happened to people who received retatrutide in human studies? The figures below help you see the change in each group at each study amount.
They aren't guesses about you. They also aren't a promise that the same change will happen outside a study.
The -24.2% body-weight figure came from 338 adults given 12 mg over 48 weeks [1]. The -82.4% liver-fat figure came from scans of 98 people after 24 weeks [5].
Those large drops may catch your eye, but they lead to a harder question: do better weight, sugar, and liver-fat numbers lead to better health? The much larger Phase 3 studies now check that.
What retatrutide changed in your body weight
Retatrutide's weight figures describe study groups; prescription-only peptide care through Promise Peptides (mypromise.com) starts with a licensed clinician's assessment of your health, which a table of averages cannot replace.
In 2023, the Phase 2 obesity study followed 338 adults for 48 weeks [1]:
A placebo is the comparison shot without retatrutide. It helps you see how much change happened without the study drug.
| Weekly amount | Average body-weight change at 48 weeks |
|---|---|
| Placebo | −2.1% |
| 1 mg | −8.7% |
| 4 mg | −17.3% |
| 8 mg | −22.8% |
| 12 mg | −24.2% |
Average weight fell more at each higher amount. At 12 mg, the average loss was almost one quarter of body weight over 48 weeks.
At that time, it was the largest average loss reported in a Phase 2 obesity drug study. The finding still leaves your long-term safety unanswered.
In 2023, the Phase 2 type 2 diabetes study followed 281 adults for 36 weeks [2]:
- At 12 mg, body weight changed −16.94%, compared with −3.00% for placebo at 36 weeks [2].
In 2022, the Phase 1b study followed 72 adults with diabetes for 12 weeks [4]:
- The highest group lost −8.96 kg more than placebo [4].
A 2024 review found lower sugar, blood pressure, and blood fats after weekly shots in Phase 2 [7]. It didn't show whether people had fewer heart attacks.
More drug brought more weight loss, but it also brought more trouble that you would have to weigh.
What retatrutide changed in the three-month blood-sugar test and daily blood sugar
In 2023, the Phase 2 diabetes study measured the three-month sugar test [2]:
This blood test shows how your sugar ran during the prior three months. Lower results mean better sugar control.
| Amount | Three-month blood-sugar change at 24 weeks |
|---|---|
| Placebo | −0.01% |
| 12 mg | −2.02% |
The −2.02% drop was large. Similar diabetes studies of approved GLP-1 hunger-hormone drugs found drops of −1.0 to −1.7%.
Those were separate studies, so the figures can't show which medicine works better for you. The report also gives change, not one normal ending number for everyone.
The Phase 1b study also checked daily sugar [4]:
- At 3 mg, average daily blood sugar fell [4].
In 2024, another review said blood fats and other heart-risk test numbers improved in the Phase 2 obesity study [8]. It didn't show fewer heart attacks, and full figures still weren't published for you to check.
What retatrutide changed in your liver fat
In 2024, the small liver study enrolled 98 people with obesity. Each had at least 10% liver fat on a scan [5].
The scan showed this liver-fat change at 24 weeks:
| Amount | Liver-fat change |
|---|---|
| Placebo | +0.3% |
| 1 mg | −42.9% |
| 4 mg | −57.0% |
| 8 mg | −81.4% |
| 12 mg | −82.4% |
At 12 mg, 86% had liver fat under the normal 5% mark by 24 weeks [5]. The drop lasted through 48 weeks and measured −86.0% for the 12 mg group [5].
This finding led TRIUMPH Phase 3 to include liver health. Your scan might improve, but this study doesn't prove that your liver will avoid lasting harm.
What Phase 2 found about harm and side effects
The retatrutide results include harm as well as weight and blood-test changes. These are the main study findings:
- Upset stomach and bowels: Nausea affected up to 45% at 12 mg. It drove most of the 18% stop rate at that amount [1].
- Faster heart rate: Heart rate rose about 5–7 beats per minute on average and reached its top near week 24 [1].
- Skin trouble at the shot site: About 8% in the Phase 2 obesity study had a reaction [1].
- Severe low blood sugar: Neither Phase 2 study recorded a case [1][2].
- Deaths: Neither Phase 2 study recorded a death [1][2].
- Muscle loss: People lost muscle along with fat. Older surgery reports showed a larger muscle share in the lost weight [4].
The report gives no exact muscle amount, so you can't tell how many pounds of muscle you might lose. TRIUMPH-3 and another large study continue to check the heart, kidneys, and whether weight stays off [9][10].
What TRIUMPH Phase 3 must prove about better health
TRIUMPH Phase 3 began after the Phase 2 retatrutide results. TRIUMPH-3 includes people with obesity who already have heart disease [9].
It asks whether the Phase 2 weight and blood-test figures lead to fewer heart attacks, hospital stays, or deaths. Another large study checks the heart and kidneys [10].
No early or final Phase 3 results had been published by mid-2026. You can compare the separate Phase 2 retatrutide and Phase 3 tirzepatide figures at retatrutide vs tirzepatide.