Retatrutide vs Mazdutide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: LY3437943, Triple G
Retatrutide is the heavy hitter of the new weight-loss drugs: a once-weekly injectable peptide that hits three receptors at once - GIP, GLP-1, and glucagon - earning it the nickname triple-G agonist. In a phase 2 trial it produced some of the largest weight loss ever recorded for a drug, up to roughly 24 percent of body weight at the top dose. It is investigational, made by Eli Lilly, and not yet FDA approved as of 2026.
Also: IBI362, LY3305677
Mazdutide is a GLP-1 and glucagon dual agonist, which puts it between semaglutide (GLP-1 only) and retatrutide (GLP-1, GIP and glucagon). It is built on oxyntomodulin, a natural gut hormone that hits both receptors, rather than on a GLP-1 backbone. It is furthest along in China, where it is approved for both weight management and type 2 diabetes. Western approval has not happened.
Key Comparison Insights
- Both peptides belong to the Weight Loss category, suggesting similar primary applications.
Detailed Comparison
| Attribute | Retatrutide | Mazdutide |
|---|---|---|
| Category | Weight Loss | Weight Loss |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Retatrutide combines three hormone signals into one molecule. The GLP-1 component curbs appetite and slows stomach emptying, the GIP component supports insulin response and may improve how fat tissue handles nutrients, and the added glucagon receptor activity is the novel piece: glucagon can increase energy expenditure and fat burning in the liver. The idea is that two arms cut how much you eat while the third raises how much you burn, which is why retatrutide is thought to push weight loss further than GLP-1-only drugs like semaglutide or even the dual GIP/GLP-1 agonist tirzepatide. The exact contribution of each receptor in humans is still being worked out, so consider the glucagon-driven energy-expenditure story a strong hypothesis rather than fully nailed down. | Two receptors, two jobs. The GLP-1 arm does the familiar work: it suppresses appetite, slows gastric emptying and improves glucose-dependent insulin release. The glucagon arm is the interesting half, because glucagon is normally thought of as the hormone that raises blood sugar. At these doses the intent is to exploit glucagon's other effects, increasing energy expenditure and pushing the liver to burn fat, while the GLP-1 arm keeps blood glucose in check and cancels out glucagon's hyperglycemic tendency. That balance is the whole design: glucagon supplies extra fat burning that GLP-1 alone cannot, and GLP-1 supplies the safety margin that makes adding glucagon viable. Reported reductions in liver fat are consistent with the glucagon component doing what it is meant to. |
| Common Dosing | 4-12 mg weekly Once weekly, same day each week | 4-6 mg weekly Once weekly |
| Administration | Subcutaneous injection weekly | Subcutaneous injection, once weekly |
| Typical Duration | Long-term use expected | Ongoing weekly use in trials, typically assessed at 24 to 48 weeks |
| Best Time to Take | Morning, same day each week | Same day each week, morning preferred |
Possible Side Effects May vary by individual |
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| Research Summary | The key human evidence is the phase 2 trial by Jastreboff and colleagues, published in the New England Journal of Medicine in 2023, which randomized 338 adults with obesity (without type 2 diabetes) over 48 weeks. Mean weight reduction reached about 24 percent at the 12 mg dose, and weight loss had not clearly plateaued by week 48, hinting the ceiling could be even higher. Among participants with prediabetes at baseline, a large majority returned to normal blood sugar. Side effects were dominated by gastrointestinal issues like nausea, vomiting, and diarrhea, the familiar pattern for this drug class, and were mostly dose-dependent. These are genuinely strong phase 2 results, but they are phase 2: larger and longer phase 3 trials are underway to confirm safety and durability, and retatrutide sold outside of trials is not an approved, quality-controlled medicine. | The pivotal trial is GLORY-1, published in the New England Journal of Medicine in 2025: 610 Chinese adults with overweight or obesity over 48 weeks. Mean weight reduction was 11.0 percent at 4 mg and 14.0 percent at 6 mg, alongside improvements in liver fat, blood pressure and lipids. A 9 mg dose has since been studied in phase 2 (about 12.8 percent at 24 weeks) and is in phase 3. Tolerability followed the pattern of the whole class, dominated by dose-dependent nausea, vomiting and diarrhea during titration. One caveat matters when reading these numbers: GLORY-1 enrolled a population with a mean BMI of 31.1, against roughly 38 in the Western trials of semaglutide and tirzepatide, so the percentages are not directly comparable to SURMOUNT-1 or STEP-1 results. There is no completed Western phase 3 program, so neither the FDA nor the EMA has assessed it, and meaningful head-to-head data against tirzepatide or retatrutide does not exist. |
Frequently Asked Questions: Retatrutide vs Mazdutide
What is the difference between Retatrutide and Mazdutide?
Retatrutide is a weight loss peptide that retatrutide is the heavy hitter of the new weight-loss drugs: a once-weekly injectable peptide that hits three receptors at once - gip, glp-1, and glucagon - earning it the nickname triple-g agonist. in a phase 2 trial it produced some of the largest weight loss ever recorded for a drug, up to roughly 24 percent of body weight at the top dose. it is investigational, made by eli lilly, and not yet fda approved as of 2026. Mazdutide is a weight loss peptide that mazdutide is a glp-1 and glucagon dual agonist, which puts it between semaglutide (glp-1 only) and retatrutide (glp-1, gip and glucagon). it is built on oxyntomodulin, a natural gut hormone that hits both receptors, rather than on a glp-1 backbone. it is furthest along in china, where it is approved for both weight management and type 2 diabetes. western approval has not happened. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Retatrutide or Mazdutide?
Neither is universally "better" - the choice depends on your specific goals. Retatrutide is typically used for weight loss purposes, while Mazdutide is used for weight loss. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Retatrutide and Mazdutide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Retatrutide and Mazdutide together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.