Retatrutide, a new injectable medication, helped adults with obesity and type 2 diabetes lose 12% to 19% of their body weight over 80 weeks in a major clinical trial, compared to just 5% weight loss with placebo. According to Gram Research analysis of this randomized controlled trial of 1,152 participants, the highest dose (12 mg weekly) produced the most weight loss at 18.8%, significantly outperforming placebo. The medication also improved blood sugar control, though gastrointestinal side effects like nausea and diarrhea were common, particularly at higher doses.
A major clinical trial tested a new injectable medication called retatrutide in over 1,100 adults with obesity and type 2 diabetes. According to Gram Research analysis, participants who received retatrutide lost significantly more weight than those on placebo, with the highest dose producing nearly 19% weight loss over 80 weeks. The medication also improved blood sugar control. While the drug showed promise, it caused common side effects like nausea and diarrhea, particularly at higher doses. This research suggests retatrutide could become an important treatment option for people struggling with both obesity and diabetes.
Key Statistics
A randomized controlled trial of 1,152 adults published in the Lancet in 2024 found that retatrutide 12 mg produced 18.8% weight loss over 80 weeks, compared to 5.1% weight loss in the placebo group.
In the TRIUMPH-2 trial, diarrhea occurred in 34% of participants receiving retatrutide 9 mg or 12 mg compared to 13% in the placebo group, making it the most common side effect.
Retatrutide 9 mg and 12 mg doses showed weight loss advantages of 11.8% and 13.8% respectively over placebo in a 1,152-person clinical trial, with improvements in blood sugar control also observed.
Among 1,152 trial participants, 84% completed the full 80-week study with retatrutide or placebo, indicating generally good tolerability despite gastrointestinal side effects.
The Quick Take
- What they studied: Whether a new injectable drug called retatrutide could help adults with obesity and type 2 diabetes lose weight and control their blood sugar better than a placebo (fake injection).
- Who participated: 1,152 adults with an average age of 55 years who had obesity (BMI of 27 or higher) and type 2 diabetes. About half were women, and most had been overweight for about 21 years and had diabetes for about 5.6 years.
- Key finding: People receiving retatrutide lost 12% to 19% of their body weight over 80 weeks, compared to just 5% weight loss in the placebo group. The highest dose (12 mg) produced the most weight loss at 18.8%, which was significantly better than placebo.
- What it means for you: If you have both obesity and type 2 diabetes, retatrutide might help you lose weight and improve blood sugar control more effectively than diet and exercise alone. However, it commonly causes digestive side effects like nausea and diarrhea that may improve over time.
The Research Details
This was a phase 3 clinical trial, which is the final stage of testing before a drug can be approved by regulatory agencies. Researchers enrolled 1,152 adults with obesity and type 2 diabetes across 92 medical centers in eight countries. Participants were randomly divided into four groups: three groups received different doses of retatrutide (4 mg, 9 mg, or 12 mg) as weekly self-injections, and one group received placebo injections. Neither the participants nor the researchers knew who was getting the real drug versus placebo, which is called a double-blind design. This design prevents bias and ensures fair comparison. The study lasted 80 weeks, and researchers measured weight loss and blood sugar control as the main outcomes. Retatrutide works by activating three different receptors in the body that control appetite, blood sugar, and metabolism. This triple action is different from other diabetes and weight loss drugs that target only one or two of these pathways.
This research approach is important because it provides strong evidence about whether retatrutide actually works and is safe. The randomized, placebo-controlled design means researchers can be confident that weight loss was caused by the drug and not by other factors like diet changes or exercise. Testing multiple doses helps doctors understand which dose works best with the fewest side effects. The large sample size and long study duration (80 weeks) mean the results are reliable and show effects that last over time.
This trial was published in the Lancet, one of the world’s most respected medical journals. The study was well-designed with proper randomization and blinding to prevent bias. A large number of participants (1,152) completed the study, which makes the results more trustworthy. The study was funded by Eli Lilly, the pharmaceutical company developing retatrutide, which is important to know when evaluating potential bias. However, the researchers were transparent about adverse events and reported all deaths and side effects honestly.
What the Results Show
Retatrutide produced substantial weight loss across all three doses tested. The 4 mg dose resulted in 11.9% weight loss, the 9 mg dose produced 16.8% weight loss, and the 12 mg dose achieved 18.8% weight loss compared to only 5.1% in the placebo group. These differences were statistically significant, meaning they were not due to chance. The weight loss advantage over placebo ranged from 6.9% to 13.8% depending on the dose. Beyond weight loss, retatrutide also improved blood sugar control in participants with type 2 diabetes, though the abstract does not provide specific numbers for this improvement. The medication’s effects were consistent throughout the 80-week study period, suggesting sustained benefit. Notably, 84% of participants completed the full study, indicating good tolerability for most people.
The study found that retatrutide improved glycemic control, meaning it helped lower and stabilize blood sugar levels in people with type 2 diabetes. This is important because better blood sugar control reduces the risk of diabetes complications like heart disease, kidney damage, and vision problems. The medication also showed promise for treating other conditions mentioned in the abstract, including knee osteoarthritis and obstructive sleep apnea, though specific results for these conditions were not detailed in the abstract provided.
Retatrutide’s weight loss results are comparable to or better than other GLP-1 receptor agonist medications like semaglutide (Ozempic, Wegovy) and tirzepatide (Zepbound, Mounjaro), which are currently approved for weight loss and diabetes. The key difference is that retatrutide targets three pathways instead of one or two, which may explain the robust weight loss. This triple-action approach represents an advancement in how these medications work. The gastrointestinal side effects observed with retatrutide are similar to those seen with other GLP-1 based medications, suggesting a class effect rather than a unique problem with retatrutide.
The study lasted 80 weeks, which is about 18 months. We don’t know yet if weight loss continues or is maintained beyond this timeframe. The study population was mostly White (58%), so results may not apply equally to all ethnic groups. Most participants were already on diabetes medications, so we don’t know how well retatrutide works as a first-line treatment. The study did not compare retatrutide directly to other weight loss or diabetes medications, only to placebo. Some participants stopped taking the medication due to side effects, particularly at higher doses, which means the real-world effectiveness might be lower than these results suggest. The study was funded by the drug manufacturer, which could introduce bias, though the researchers reported adverse events transparently.
The Bottom Line
Retatrutide appears to be an effective treatment option for adults with both obesity and type 2 diabetes who have not achieved adequate weight loss through diet and exercise alone. The 9 mg and 12 mg doses showed the best results, though the 12 mg dose had more side effects and treatment discontinuations. Start with a lower dose and increase gradually to minimize gastrointestinal side effects. This medication should only be used under medical supervision and is not appropriate for everyone. People with a personal or family history of thyroid cancer or multiple endocrine neoplasia should not use this medication. Confidence level: High for weight loss benefit, Moderate for long-term safety and durability of effects.
Adults with obesity (BMI 27 or higher) and type 2 diabetes who have struggled to lose weight through lifestyle changes should discuss retatrutide with their doctor. People with well-controlled type 2 diabetes using diet and exercise alone may not need this medication. Pregnant women, people with a history of thyroid cancer, and those with severe kidney or liver disease should not use retatrutide. People who experience severe nausea, vomiting, or other side effects may need to stop the medication or switch to a lower dose.
Weight loss typically begins within the first few weeks of treatment as the medication starts affecting appetite and metabolism. Significant weight loss (10% or more) usually occurs within 3 to 6 months. Maximum weight loss benefits appear to be reached by 80 weeks (about 18 months) based on this study. Blood sugar improvements may occur even faster, sometimes within days to weeks. However, if you stop taking retatrutide, weight loss may reverse over time, so this appears to be a long-term treatment rather than a short-term solution.
Frequently Asked Questions
How much weight can you lose with retatrutide?
In the TRIUMPH-2 trial of 1,152 adults, retatrutide produced 12% to 19% weight loss depending on dose over 80 weeks, compared to 5% with placebo. The 12 mg dose achieved the most weight loss at 18.8%, though it also caused more side effects.
What are the side effects of retatrutide?
The most common side effects are gastrointestinal, including diarrhea (27% to 34% of users) and nausea (14% to 28%). Less common side effects include low blood pressure and nerve tingling. About 8% to 12% of people on higher doses stopped treatment due to side effects.
Is retatrutide approved by the FDA?
This trial was completed in 2024, but retatrutide has not yet received FDA approval as of the publication date. The drug is still under review by regulatory agencies. Approval decisions typically follow publication of clinical trial results like this study.
How does retatrutide work for weight loss?
Retatrutide activates three different receptors in the body that control appetite, blood sugar, and metabolism. This triple action reduces hunger, increases feelings of fullness, and improves how the body processes glucose, leading to weight loss and better blood sugar control.
Can retatrutide replace diet and exercise for weight loss?
Retatrutide works best combined with healthy eating and physical activity, not as a replacement. The trial enrolled people with a history of unsuccessful diet attempts, suggesting medication works alongside lifestyle changes. Your doctor can help determine if retatrutide is appropriate for your situation.
Want to Apply This Research?
- Log weekly body weight and waist circumference measurements, plus weekly blood sugar readings (fasting glucose or HbA1c if available). Track gastrointestinal symptoms daily (nausea, diarrhea, constipation) on a 0-10 scale to identify patterns and discuss with your doctor. Record energy levels and appetite changes to monitor medication effectiveness.
- Use the app to set a realistic weight loss goal (1 to 2 pounds per week) and track progress toward it. Log meals and water intake to support the medication’s appetite-suppressing effects. Set reminders for weekly injections and doctor appointments. Track which foods trigger nausea or digestive issues so you can adjust your diet accordingly. Use the app’s mood and energy tracking to monitor overall wellbeing during treatment.
- Establish a baseline of current weight, blood sugar, and symptoms before starting retatrutide. Check weight weekly and blood sugar as recommended by your doctor (typically monthly initially, then quarterly). Review trends monthly with your healthcare provider to assess if the dose is working well or needs adjustment. Track side effects continuously and report severe or persistent symptoms immediately. Schedule follow-up appointments every 3 to 6 months to monitor long-term effectiveness and safety. Use the app to generate reports showing your progress to share with your doctor.
This article summarizes clinical trial results for educational purposes and should not be considered medical advice. Retatrutide is not yet approved by the FDA and is still under investigation. Do not start, stop, or change any diabetes or weight loss medication without consulting your healthcare provider. This medication may not be appropriate for everyone, particularly those with a personal or family history of thyroid cancer, multiple endocrine neoplasia, or severe kidney or liver disease. Pregnant women should not use retatrutide. If you experience severe side effects, contact your doctor immediately. The information presented reflects the study’s findings and should be discussed with your healthcare team to determine if retatrutide is right for your individual situation.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.