In people with type 2 diabetes, retatrutide lowered both blood sugar and body weight. In the phase 3 trial TRANSCEND-T2D-1, glycated haemoglobin fell by 1.94 points after 40 weeks at 12 mg, and body weight by 15.3 percent. In the phase 2 trial, doses from 8 mg lowered blood sugar more than dulaglutide, a GLP-1 medicine used in diabetes. Below we collect the results of three trials in people with diabetes, dose by dose.
Why is retatrutide studied in type 2 diabetes?
Retatrutide acts on three receptors at once: GLP-1, GIP and the glucagon receptor. The first two are receptors for gut hormones that increase insulin release after a meal. Semaglutide and tirzepatide act on the same receptors, and both are approved for treating type 2 diabetes.
The authors of the phase 2 trial point to one more reason. According to current guidelines, weight control in type 2 diabetes is as important as controlling blood sugar. A medicine that does both at once answers two treatment goals at the same time.
What did the phase 2 trial show?
The phase 2 trial included 281 adults with type 2 diabetes at 42 centres in the United States. The results were published in 2023 in The Lancet. Participants had had diabetes for an average of 8.1 years and were treated with diet, exercise or metformin. Several retatrutide doses were compared with placebo and with dulaglutide 1.5 mg.
| Group | HbA1c fall after 24 weeks | Weight loss after 36 weeks |
|---|---|---|
| Retatrutide 0.5 mg | 0.43 points | 3.19 percent |
| Retatrutide 4 mg | 1.30 to 1.39 points | 7.92 to 10.37 percent |
| Retatrutide 8 mg | 1.88 to 1.99 points | 16.34 to 16.81 percent |
| Retatrutide 12 mg | 2.02 points | 16.94 percent |
| Dulaglutide 1.5 mg | 1.41 points | 2.02 percent |
| Placebo | 0.01 points | 3.00 percent |
The ranges at 4 and 8 mg come from two starting variants, from 2 mg or from a higher dose. At 8 mg with a slow start and at 12 mg the fall in blood sugar was significantly greater than with dulaglutide. From 4 mg upwards retatrutide lowered body weight clearly more than dulaglutide and placebo. The results after 36 weeks confirmed what was seen after 24.
What did TRANSCEND-T2D-1 show?
TRANSCEND-T2D-1 is a phase 3 trial in which retatrutide was the only glucose-lowering medicine. It included 537 people whose diabetes was no longer controlled by diet and exercise. Their diabetes was recent, on average 2.5 years, and their average BMI was 35.8. The results were published in June 2026 in The Lancet.
| Result after 40 weeks | 4 mg | 9 mg | 12 mg | Placebo |
|---|---|---|---|---|
| HbA1c fall | 1.69 points | 1.86 points | 1.94 points | 0.81 points |
| Weight loss | 11.5 percent | 13.9 percent | 15.3 percent | 2.6 percent |
At the start, average glycated haemoglobin was 7.9 percent. A fall of 1.94 points at 12 mg therefore brings the average to around 6 percent. 91 percent of participants completed treatment for the whole trial.
Nobody in this trial had severe hypoglycaemia, a dangerous fall in blood sugar. Side effects were mostly mild or moderate, concerned the digestive tract and eased over time. Between 2 and 5 percent of people on retatrutide stopped treatment because of them.
What did TRIUMPH-2 show?
TRIUMPH-2 tested retatrutide in people with obesity and type 2 diabetes for 80 weeks. It included 1152 people at 92 centres in eight countries. The average BMI was 38.2 and diabetes had lasted an average of 5.6 years. The results appeared on 29 September 2026 in The Lancet.
After 80 weeks body weight fell by 11.9 percent at 4 mg, by 16.8 percent at 9 mg and by 18.8 percent at 12 mg. In the placebo group it was 5.1 percent. The authors also report improved blood sugar control, but the summary of the paper does not give these figures. 84 percent of participants completed treatment to the end.
What happens to appetite and body fat?
At doses from 4 mg, participants with diabetes reported lower appetite and less hunger already after 24 weeks. This comes from a separate analysis of the phase 2 trial, published in 2025. At 8 and 12 mg the tendency to overeat, for example under stress, also fell. The more hunger fell, the greater the weight loss.
A second analysis of the same trial measured body composition with DXA, a low-dose X-ray scan. Body fat fell after 36 weeks by 23.2 percent at 12 mg and by 26.1 percent at 8 mg. In the placebo group it was 4.5 percent. The share of lean mass in the total loss was similar to that seen with other obesity medicines.
What about the kidneys, blood fats and inflammation?
At 12 mg the amount of protein in the urine fell by 37.0 percent compared with placebo in people with diabetes. Protein in the urine is one of the first signs of strain on the kidneys. Kidney filtration did not change compared with placebo. This result comes from an analysis published in 2025 in Kidney International Reports.
Retatrutide also lowered blood fats linked to the risk of heart disease. In people with diabetes non-HDL cholesterol fell by up to 21.0 percent and apolipoprotein B by 21.4 percent. These are the results of a 2026 analysis covering both phase 2 trials.
How does retatrutide compare with tirzepatide?
A direct comparison of the two molecules in people with diabetes has not yet been published. The results of separate trials can, however, be set side by side, keeping in mind the differences between the groups. In five SURPASS trials tirzepatide lowered glycated haemoglobin by 1.87 to 2.58 points. The details are in the guide on tirzepatide and the SURPASS trials.
In TRANSCEND-T2D-1 retatrutide gave up to 1.94 points in recently diagnosed diabetes. Body weight is a strong point of retatrutide, because the 15.3 percent loss after 40 weeks was achieved with retatrutide alone, without other medicines. A comparison of the three molecules in people without diabetes is in the guide semaglutide vs tirzepatide vs retatrutide.
Where to buy retatrutide?
In the shop, retatrutide comes in three versions from three manufacturers. Retatrutide 20 mg Bio-Peptide costs 200 EUR and is in stock. Retatrutide 20 mg Genheal costs 200 EUR and is available on backorder. Retatrutide 40 mg Nouveaux in a pen costs 350 EUR, so 8.75 EUR per milligram instead of 10 EUR.
Retatrutide is not an approved medicine, and the products in the shop are material for laboratory research. Diabetes treatment is managed by a doctor, and no research material replaces it. The course of weight loss over the months is described in the guide on retatrutide results, and all versions are on the retatrutide page.
Frequently asked questions
How much does retatrutide lower blood sugar in type 2 diabetes?
In TRANSCEND-T2D-1 glycated haemoglobin fell after 40 weeks by 1.69 to 1.94 points, depending on the dose. In the placebo group the fall was 0.81 points.
Does retatrutide work better than dulaglutide?
In the phase 2 trial, 8 mg with a slow start and 12 mg lowered blood sugar significantly more than dulaglutide 1.5 mg. They lowered body weight several times more.
How much weight do people with diabetes lose on retatrutide?
In TRIUMPH-2 body weight fell after 80 weeks by 18.8 percent at 12 mg. In TRANSCEND-T2D-1 it was 15.3 percent after 40 weeks.
Did retatrutide cause dangerous falls in blood sugar?
In the phase 2 trial and in TRANSCEND-T2D-1 not a single case of severe hypoglycaemia was recorded. The most common side effects concerned the digestive tract.
Is retatrutide a diabetes medicine?
It is not yet approved in any country. The results of two phase 3 trials in people with type 2 diabetes were published in 2026.
Sources
- Rosenstock J, Frias J, Jastreboff AM et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a phase 2 trial conducted in the USA. The Lancet, 2023, 402(10401): 529-544. https://doi.org/10.1016/S0140-6736(23)01053-X
- Bajaj HS, Welch M, Shah P et al. Efficacy and safety of retatrutide in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1). The Lancet, 2026, 407(10546): 2402-2413. https://doi.org/10.1016/S0140-6736(26)00967-0
- Bellido V, le Roux CW, Ekinci EI et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2). The Lancet, 2026. https://doi.org/10.1016/S0140-6736(26)01861-1
- Kanu C, Boye KS, Poon JL et al. Appetite, eating attitudes, and eating behaviours during treatment with retatrutide in adults with type 2 diabetes: Results of a phase 2 study. Diabetes, Obesity and Metabolism, 2025, 27(12): 6988-6998. https://doi.org/10.1111/dom.70097
- Coskun T, Wu Q, Schloot NC et al. Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2 trial. The Lancet Diabetes and Endocrinology, 2025, 13(8): 674-684. https://doi.org/10.1016/S2213-8587(25)00092-0
- Heerspink HJL, Lu Z, Du Y et al. The Effect of Retatrutide on Kidney Parameters in Participants With Type 2 Diabetes Mellitus and/or Obesity. Kidney International Reports, 2025, 10(6): 1980-1992. https://doi.org/10.1016/j.ekir.2025.03.049
- Ruotolo G, Harris C, Lin Y et al. Retatrutide-Associated Improvements in Cardiovascular Risk Biomarkers in Adults With Obesity With or Without Type 2 Diabetes. Diabetes, Obesity and Metabolism, 2026. https://doi.org/10.1111/dom.71200