Pemvidutide
Also known as: ALT-801
A weekly weight loss injection from Altimmune that targets two hormones (GLP-1 for appetite, glucagon for fat-burning) — similar to mazdutide and survodutide. Particularly being developed for fatty liver disease (MASH) alongside obesity. Phase 2b results showed around 15.6% body weight loss at 48 weeks, with significant reductions in liver fat. Also branded as ALT-801. Now in Phase 3 trials for both indications.
Dosage
Fixed dose: 1.2-2.4 mg subcutaneous weekly (titrated)
Dosages shown are for research reference only. Always consult a qualified healthcare provider.
Administration
Subcutaneous injection (once weekly)
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Effects
Weight Loss
Approximately 15.6% mean body weight loss at 48 weeks in Phase 2b obesity trial.
Liver Fat Reduction
Significant reductions in liver fat content alongside fibrosis improvements in MASH trials.
Energy Expenditure
Glucagon receptor activation drives hepatic fat oxidation and thermogenesis.
Appetite Suppression
GLP-1 component provides standard central appetite suppression.
Mechanism of Action
Pemvidutide (ALT-801) is a once-weekly subcutaneous dual GLP-1 and glucagon receptor agonist, mechanistically similar to mazdutide and survodutide but with a distinct molecular design and a primary development focus on metabolic dysfunction-associated steatohepatitis (MASH) alongside obesity. The dual mechanism combines appetite suppression with enhanced energy expenditure and direct hepatic fat mobilisation.
The GLP-1 receptor component drives the established central appetite suppression through hypothalamic and brainstem signalling, slows gastric emptying, and stimulates glucose-dependent insulin secretion. The glucagon receptor agonism component is what differentiates pemvidutide from pure GLP-1 drugs — glucagon binding in hepatocytes activates adenylyl cyclase and protein kinase A, driving up fatty acid beta-oxidation and ketogenesis while reducing de novo lipogenesis. This directly mobilises stored hepatic triglycerides for energy use rather than continued storage, addressing the core pathology of MASH. In adipose tissue and beyond, glucagon signalling also raises whole-body energy expenditure through thermogenic and futile-cycle mechanisms.
The receptor potency ratio is balanced so that glucagon-driven hepatic glucose output is offset by GLP-1-driven insulinotropic effects, yielding net glycemic improvement alongside enhanced fat oxidation. Phase 2b results in obesity demonstrated approximately 15.6% mean body weight loss at 48 weeks, and parallel MASH trials showed significant reductions in liver fat content alongside improvements in fibrosis markers. Phase 3 trials in both obesity and MASH are now underway, positioning pemvidutide as Altimmune's lead asset and a competitor to mazdutide and survodutide in the dual GLP-1/glucagon class.
Regulatory Status
Not yet FDA approved. Phase 3 trials in obesity and MASH ongoing in 2026 (Altimmune, also referred to by code name ALT-801).
Risks & Safety
Common
nausea, vomiting, diarrhea, decreased appetite.
Serious
pancreatitis, gallstones, slightly elevated heart rate (a known signal for glucagon receptor agonists), changes in liver enzymes (typically improvements in MASH patients but worth monitoring).
Rare
thyroid C-cell tumour class warning, severe allergic reactions.
Compare Pemvidutide With
Research Papers
5Published: March 25, 2026
AI Summary
A meta-analysis of randomised trials found pemvidutide significantly cut liver fat, liver enzymes, body weight and blood pressure in MASH/MASLD versus placebo. Larger, longer trials are still needed to confirm reduction in liver fibrosis.
Published: December 6, 2025
AI Summary
In the IMPACT phase 2b trial of 212 patients with biopsy-confirmed MASH, pemvidutide resolved MASH in over half of those treated versus 20% on placebo at 24 weeks. However, it did not significantly improve liver fibrosis at this timepoint.
Published: November 1, 2025
AI Summary
Extending pemvidutide treatment from 12 to 24 weeks in 64 patients with fatty liver disease cut liver fat content by 56-76%, with over half normalising liver fat at the 1.8 mg dose. Body weight also dropped about 6%.
Published: January 1, 2025
AI Summary
In the first pemvidutide MASLD trial (94 adults, 12 weeks), the drug cut liver fat by 47-69% versus 4.4% on placebo. The 1.8 mg dose worked best for liver fat, ALT and weight loss with no serious adverse events.
Published: July 24, 2025
AI Summary
This review places pemvidutide alongside other emerging GLP-1/glucagon co-agonists like survodutide, mazdutide and retatrutide that are showing significant weight loss in trials. The authors flag cost, access and long-term safety as open questions.
Frequently Asked Questions
What is Pemvidutide?
A weekly weight loss injection from Altimmune that targets two hormones (GLP-1 for appetite, glucagon for fat-burning) — similar to mazdutide and survodutide. Particularly being developed for fatty liver disease (MASH) alongside obesity. Phase 2b results showed around 15.6% body weight loss at 48 weeks, with significant reductions in liver fat. Also branded as ALT-801. Now in Phase 3 trials for both indications.
What is Pemvidutide used for?
A weekly weight loss injection from Altimmune that targets two hormones (GLP-1 for appetite, glucagon for fat-burning) — similar to mazdutide and survodutide. Particularly being developed for fatty liver disease (MASH) alongside obesity. Phase 2b results showed around 15.6% body weight loss at 48 weeks, with significant reductions in liver fat. Also branded as ALT-801. Now in Phase 3 trials for both indications.
What is the dosage for Pemvidutide?
Phase 2b/3 trials: 1.2-2.4 mg subcutaneous once weekly with stepwise dose escalation over 12 weeks. Both higher and lower dose arms being tested to balance weight loss against tolerability and the cardiovascular effects of glucagon receptor activation.
What are the side effects of Pemvidutide?
Common: nausea, vomiting, diarrhea, decreased appetite. Serious: pancreatitis, gallstones, slightly elevated heart rate (a known signal for glucagon receptor agonists), changes in liver enzymes (typically improvements in MASH patients but worth monitoring). Rare: thyroid C-cell tumour class warning, severe allergic reactions.
How does Pemvidutide work?
Pemvidutide (ALT-801) is a once-weekly subcutaneous dual GLP-1 and glucagon receptor agonist, mechanistically similar to mazdutide and survodutide but with a distinct molecular design and a primary development focus on metabolic dysfunction-associated steatohepatitis (MASH) alongside obesity. The dual mechanism combines appetite suppression with enhanced energy expenditure and direct hepatic fat mobilisation. The GLP-1 receptor component drives the established central appetite suppression through hypothalamic and brainstem signalling, slows gastric emptying, and stimulates glucose-dependent insulin secretion. The glucagon receptor agonism component is what differentiates pemvidutide from pure GLP-1 drugs — glucagon binding in hepatocytes activates adenylyl cyclase and protein kinase A, driving up fatty acid beta-oxidation and ketogenesis while reducing de novo lipogenesis. This directly mobilises stored hepatic triglycerides for energy use rather than continued storage, addressing the core pathology of MASH. In adipose tissue and beyond, glucagon signalling also raises whole-body energy expenditure through thermogenic and futile-cycle mechanisms. The receptor potency ratio is balanced so that glucagon-driven hepatic glucose output is offset by GLP-1-driven insulinotropic effects, yielding net glycemic improvement alongside enhanced fat oxidation. Phase 2b results in obesity demonstrated approximately 15.6% mean body weight loss at 48 weeks, and parallel MASH trials showed significant reductions in liver fat content alongside improvements in fibrosis markers. Phase 3 trials in both obesity and MASH are now underway, positioning pemvidutide as Altimmune's lead asset and a competitor to mazdutide and survodutide in the dual GLP-1/glucagon class.
How is Pemvidutide administered?
Pemvidutide is administered via subcutaneous injection (once weekly).
What is the half-life of Pemvidutide?
The half-life of Pemvidutide is Approximately 168 hours (7 days), supporting once-weekly dosing.
Is Pemvidutide legal?
Not yet FDA approved. Phase 3 trials in obesity and MASH ongoing in 2026 (Altimmune, also referred to by code name ALT-801).
Sources. This profile is built from peer-reviewed papers indexed on PubMed, FDA-approved labelling where available, and published clinical guidelines. The 5 primary sources used are listed in the Research Papers section above, each linked to its PubMed entry. See our editorial standards for how we research and review peptide profiles.
Last reviewed. by the Peptide Reference Editorial Team. Spot an error? Email a correction.
Not medical advice. Information on this page is for educational and research reference only. Many peptides covered are not approved for human use. See our full medical disclaimer.
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