Pemvidutide vs Retatrutide
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: ALT-801
Pemvidutide is Altimmune's once-weekly GLP-1/glucagon dual agonist, now being developed mainly for MASH (fatty liver disease with inflammation, formerly called NASH). It cleared fat out of the liver fast in trials and earned FDA Breakthrough Therapy designation, and its phase 3 trial (PERFORMA) started in August 2026. It also produced decent weight loss in an obesity trial, but it is not approved anywhere and its biggest phase 2 MASH trial missed on the fibrosis endpoint at 24 weeks.
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 phase 2 it produced about 24 percent weight loss at the top dose, and in the phase 3 TRIUMPH-1 trial Lilly reported 28.3 percent at 12 mg over 80 weeks. It is investigational, made by Eli Lilly, and not FDA approved; Lilly plans to file with the FDA in the first quarter of 2027. Because it is not an approved drug, FDA says it cannot be legally compounded.
Key Comparison Insights
- Pemvidutide is categorized as Metabolic, while Retatrutide is Weight Loss.
Detailed Comparison
| Attribute | Pemvidutide | Retatrutide |
|---|---|---|
| Category | Metabolic | 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 | Pemvidutide activates two receptors in roughly balanced fashion. The GLP-1 side cuts appetite and slows stomach emptying, like semaglutide. The glucagon side acts directly on the liver, pushing it to burn fat and raising energy expenditure, which is why this drug class is especially interesting for fatty liver. Altimmune attaches its EuPort domain to stretch the half-life for weekly dosing and, the company says, to slow absorption for better tolerability. Glucagon activity can raise blood sugar on its own, so balancing the two signals is the design challenge. Most of the mechanism story comes from the company and is plausible, but independent data are limited. | 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. |
| Common Dosing | 1.2-1.8 mg once weekly (MASH trial doses) Once weekly | 4-12 mg weekly Once weekly, same day each week |
| Administration | Subcutaneous injection once weekly | Subcutaneous injection weekly |
| Typical Duration | 24-48 weeks in completed trials; phase 3 runs 52 weeks for the biopsy endpoint and years for outcomes | Long-term use expected |
| Best Time to Take | Same day each week | Morning, same day each week |
Possible Side Effects May vary by individual |
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| Research Summary | In the phase 2 MOMENTUM obesity trial (391 adults without diabetes, 48 weeks), the 2.4 mg weekly dose produced 15.6% mean weight loss versus 2.2% on placebo, and a small MRI sub-study (50 people) found about 78% of the weight lost was fat. The focus then shifted to MASH. The phase 2b IMPACT trial randomized 212 people with biopsy-confirmed MASH and F2-F3 fibrosis to 1.2 mg, 1.8 mg or placebo. At 24 weeks, MASH resolution was 59.1% and 52.1% versus 19.1% on placebo, a strong result. But fibrosis improvement (31.8% and 34.5% versus 25.9%) was not statistically significant, and the stock fell by more than half on the news in June 2025. The 48-week data (December 2025) showed significant improvements in non-invasive fibrosis markers (ELF score and liver stiffness) and continued weight loss without a plateau, with fewer dropouts for side effects than placebo. The PERFORMA phase 3 trial (about 1,790 people, titrating to 1.8 or 2.4 mg) began in August 2026, with a 52-week biopsy readout expected in 2029. A separate phase 2 trial in alcohol use disorder (RECLAIM) reported positive topline results in July 2026. Bottom line: strong on liver fat and MASH resolution, still unproven on the fibrosis outcomes regulators care most about. | The first big human evidence was the phase 2 trial by Jastreboff and colleagues (New England Journal of Medicine, 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. In a liver-fat substudy of 98 participants, liver fat dropped by about 81 to 82 percent at the 8 and 12 mg doses by week 24. Phase 3 has since read out: in TRIUMPH-1, Lilly reported mean weight loss of 19.0, 25.9 and 28.3 percent at 4, 9 and 12 mg over 80 weeks versus 2.2 percent on placebo (efficacy estimand, which assumes people stayed on the drug; analyses counting everyone randomized come out a few points lower). TRIUMPH-2 (type 2 diabetes plus obesity) reached about 20.8 percent at 12 mg, and TRIUMPH-3 (severe obesity plus heart disease) about 22.6 percent. Side effects were dominated by dose-dependent gastrointestinal issues like nausea, vomiting, and diarrhea, plus a dysesthesia (skin sensitivity) signal at the top dose. Retatrutide sold outside of trials is not an approved, quality-controlled medicine. |
Frequently Asked Questions: Pemvidutide vs Retatrutide
What is the difference between Pemvidutide and Retatrutide?
Pemvidutide is a metabolic peptide that pemvidutide is altimmune's once-weekly glp-1/glucagon dual agonist, now being developed mainly for mash (fatty liver disease with inflammation, formerly called nash). it cleared fat out of the liver fast in trials and earned fda breakthrough therapy designation, and its phase 3 trial (performa) started in august 2026. it also produced decent weight loss in an obesity trial, but it is not approved anywhere and its biggest phase 2 mash trial missed on the fibrosis endpoint at 24 weeks. 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 phase 2 it produced about 24 percent weight loss at the top dose, and in the phase 3 triumph-1 trial lilly reported 28.3 percent at 12 mg over 80 weeks. it is investigational, made by eli lilly, and not fda approved; lilly plans to file with the fda in the first quarter of 2027. because it is not an approved drug, fda says it cannot be legally compounded. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Pemvidutide or Retatrutide?
Neither is universally "better" - the choice depends on your specific goals. Pemvidutide is typically used for metabolic purposes, while Retatrutide is used for weight loss. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Pemvidutide and Retatrutide be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Pemvidutide and Retatrutide 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.