Reviewed & approved by Dr. Nova Reyes · Last checked 2026-10-25. ← Back to Evidence Library

Pemvidutide: what the evidence says

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

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What is it?

Pemvidutide (also called ALT-801) is a lab-made peptide that activates both the GLP-1 receptor and the glucagon receptor in a balanced way. ^{R1, R3} GLP-1 action lowers appetite. Glucagon may increase the energy the body burns and act directly on the liver to burn fat. ^{R2, R3} Unknown How much the glucagon part adds in people, compared with GLP-1 action alone, has not been tested directly in a published trial.

Survodutide and mazdutide also act on these two receptors; see the survodutide page and the mazdutide page.

Does it help fatty liver disease (MASH)?

MASH (metabolic dysfunction-associated steatohepatitis) is fatty liver with inflammation that can lead to scarring and cirrhosis. All results below are from trials funded by Altimmune.

• Human IMPACT (phase 2b biopsy trial): in 212 adults with MASH and moderate to advanced scarring, MASH cleared without worse scarring in 58% and 52% on the two pemvidutide arms vs 20% on placebo. Scarring improved in 33% and 36% vs 28%, which was not a significant difference. ^R1 An independent commentary appeared alongside the paper. ^R4
• Human Company update on IMPACT: Altimmune reports that, with longer treatment, blood and scan-based scarring markers improved more than on placebo. ^{R7, R8} [UNVERIFIED: company figures, not yet in a peer-reviewed paper.]
• Human Liver-fat trial (smaller): in 94 adults with fatty liver, liver fat on MRI fell by 46.6% to 68.5% vs 4.4% on placebo. ^R3 In the 64 who continued in an extension, liver fat fell by 56.3% to 76.4% vs 14.0%. ^R2
• Human Meta-analysis: an independent pooled analysis of these trials found lower liver fat, liver enzymes and weight than placebo, and said larger, longer trials are needed to confirm any effect on scarring. ^R5
• Unknown Whether pemvidutide prevents cirrhosis, liver failure or liver cancer. A phase 3 trial is recruiting. ^R9

Does it help weight loss?

• Human In the peer-reviewed liver trials (Limited evidence), weight fell by up to 4.3% vs placebo in the smaller trial and by 6.2% vs placebo in its extension, and a 2026 GRADE (evidence-quality-graded) meta-analysis confirmed a pooled weight reduction over placebo. ^{R2, R3, R5}
• Human MOMENTUM (phase 2, obesity without diabetes; Very limited evidence on its own): in 391 adults, Altimmune reported average weight change of −10.3%, −11.2% and −15.6% on three pemvidutide arms vs −2.2% on placebo. Because this trial rests on a company release and conference abstract alone rather than a peer-reviewed journal paper, specific claims from MOMENTUM are rated Very limited. ^R6 [UNVERIFIED: company release and conference abstract; no peer-reviewed paper found on PubMed.]
• Unknown Altimmune's current focus is liver disease; we found no phase 3 obesity trial. ^{R8, R9}

Does it help type 2 diabetes?

• Unknown No trial with blood sugar as its main goal was found. In MOMENTUM, which excluded people with diabetes, the company reported no meaningful change in HbA1c (average blood sugar). ^R6 [UNVERIFIED: company figure.]

Is it safe?

What the trials reported:

• Caution IMPACT: side effects were reported in 78% and 81% on pemvidutide vs 67% on placebo, mostly mild or moderate. Stopping because of side effects was rare (0% and 1% vs 2%). ^R1
• Caution MOMENTUM: Altimmune reported nausea in 25.5% to 59.6% vs 11.3% on placebo and vomiting in 6.1% to 27.8% vs 3.1%. About 1 in 5 on the two higher arms stopped because of side effects, vs 6.2% on placebo. No major heart events were reported. ^R6 [UNVERIFIED: company figures.]
• Caution GLP-1 class risks: pemvidutide acts on the GLP-1 receptor, so the risks known for that drug class (pancreatitis, gallbladder disease, rodent thyroid tumors, low blood sugar with insulin or sulfonylureas, older blood-sugar-lowering pills) are reasonable to expect; see the semaglutide page. Unknown The abstracts we reviewed do not report rates of these events.
• Unknown Heart safety: no heart-outcome trial was found.
• Unknown Long-term safety and rare harms are unknown.

Compounded and gray-market pemvidutide: extra risks

• Caution Unregulated "research" vials. Because pemvidutide is only used inside clinical trials, any vial sold online has no regulatory quality control, and its identity, strength and sterility are unknown.
• Caution Don't stack with other GLP-1 drugs. Taking pemvidutide with semaglutide, tirzepatide, retatrutide or similar drugs means two drugs acting on the same receptor, which no trial on this page tested. Unknown
• Caution Measuring mistakes. FDA has reported people hospitalized after drawing up too much from multi-injection GLP-1 vials. The same syringe-marking problem applies here. See the section on measuring mistakes on our semaglutide page.

What we don't know

• Unknown What is actually in a given gray-market vial
• Unknown Whether pemvidutide reverses liver scarring or improves liver outcomes ^{R1, R9}
• Unknown Peer-reviewed weight-loss results from MOMENTUM
• Unknown Whether it is safe for the heart over many years
• Unknown Whether it helps alcohol use disorder or alcohol-related liver disease ^R9

Is it legal?

Not FDA-approved; no Drugs@FDA record was found (openFDA search, Oct 24, 2026). Altimmune says FDA granted Breakthrough Therapy designation for MASH (January 2026) and Fast Track designations for MASH and alcohol use disorder. ^{R7, R8} [UNVERIFIED: company source; FDA does not publish these designations.] A designation speeds review; it is not an approval. We found no announced filing for approval. EU, Japan, China: UNVERIFIED not checked against EMA, PMDA or NMPA. WADA: not named on the 2026 Prohibited List; S0 bans at all times any unapproved substance in development that no other section covers, which describes Pemvidutide ^R10. WADA has not ruled on Pemvidutide by name. As of Oct 24, 2026.

What's in the vial?

Real pemvidutide is only available inside clinical trials. We have not found published lab tests of gray-market pemvidutide. Under the Open Peptide Standard, a GLP-1 vial overfilled by more than 20% is a critical fail (draft threshold). See results at /tests/. A passing test covers one batch, tested on one date. It does not mean the compound itself is safe.

What do users report?

Self-report, not evidence.

Unknown TBD. We'll only list this once we can cite a public source.

Study details

These are doses researchers used, not recommendations. All trials funded by Altimmune. All injections subcutaneous, once weekly.

R1–R3, R6 Human: Liver and weight trials

Study	People	Route	Dose used	Follow-up	Reported	Side effects / dropouts	Citation
IMPACT (Noureddin 2025), MASH F2–F3, phase 2b, NCT05989711	212 (41 / 85 vs 86)	Subcutaneous	1.2 or 1.8 mg once weekly, no titration, vs placebo	24 wk primary (48 wk trial)	MASH resolution 58%, 52% vs 20%; fibrosis improvement 33%, 36% vs 28% (p=0.59, 0.27)	AEs 78%, 81% vs 67%; AE discontinuation 0%, 1% vs 2%	PMID 41237796
Harrison 2025, MASLD, NCT05006885	94	Subcutaneous	1.2, 1.8 or 2.4 mg once weekly vs placebo	12 wk	Liver fat −46.6%, −68.5%, −57.1% vs −4.4%; weight up to −4.3% (1.8 mg)	No severe or serious AEs	PMID 39002641
Browne 2025, extension, NCT05292911	64	Subcutaneous	Same arms continued	24 wk total	Liver fat −56.3%, −75.2%, −76.4% vs −14.0%; weight −6.2%	Low side-effect rates reported	PMID 41113119
MOMENTUM (company), obesity, no diabetes	391 (≈97–99 per arm)	Subcutaneous	1.2, 1.8 mg (no titration) or 2.4 mg (4 wk titration) once weekly vs placebo + diet and exercise	48 wk	−10.3%, −11.2%, −15.6% vs −2.2%; ≥20% loss 32.1% on 2.4 mg	Nausea 25.5–59.6% vs 11.3%; AE discontinuation 5.1%, 19.2%, 19.6% vs 6.2%	Altimmune release, Nov 30, 2023; ADA 2024 abstract doi:10.2337/db24-262-or UNVERIFIED

R4, R5 Commentary and pooled analysis

• R4 Tacke 2025, Lancet comment on IMPACT. PMID 41352959
• R5 Rajab 2026, GRADE-assessed meta-analysis of pemvidutide RCTs. PMID 41879841

R7–R9 Regulatory and ongoing trials (as of Oct 24, 2026)

• R7 Altimmune press release, Breakthrough Therapy designation for MASH (January 2026); 48-week IMPACT topline (December 2025). UNVERIFIED Company source.
• R8 Altimmune, 48-week IMPACT data at EASL 2026, May 28, 2026: weight −7.5% on 1.8 mg at 48 wk; ~1% stopped for AEs; Fast Track for MASH and AUD. Also Q1 2026 update: PERFORMA phase 3 planned for 2H 2026. UNVERIFIED Company source.
• R9 ClinicalTrials.gov: phase 3 MASH NCT07795164 (recruiting); RECLAIM, alcohol use disorder NCT06987513 (completed, no results posted); RESTORE, alcohol-related liver disease NCT07009860 (active, not recruiting).
• FDA: no Drugs@FDA record (openFDA query, Oct 24, 2026). EMA, PMDA, NMPA: UNVERIFIED not checked.

Full reference list (all PMIDs verified on PubMed, Oct 24, 2026)

1. Noureddin M, et al. Lancet. 2025;406(10520):2644-2655. doi:10.1016/S0140-6736(25)02114-2. PMID 41237796
2. Browne SK, et al. JHEP Rep. 2025;7(11):101483. doi:10.1016/j.jhepr.2025.101483. PMID 41113119
3. Harrison SA, et al. J Hepatol. 2025;82(1):7-17. doi:10.1016/j.jhep.2024.07.006. PMID 39002641
4. Tacke F. Lancet. 2025;406(10520):2604-2606. doi:10.1016/S0140-6736(25)02304-9. PMID 41352959
5. Rajab I, et al. Naunyn Schmiedebergs Arch Pharmacol. 2026;399(9):14553-14560. doi:10.1007/s00210-026-05257-1. PMID 41879841
6. Altimmune. MOMENTUM topline press release, Nov 30, 2023 (link in Study details, R6); ADA 2024 abstract 262-OR, doi:10.2337/db24-262-or
7. Altimmune. Breakthrough Therapy designation press release, January 2026. https://ir.altimmune.com/news-releases/news-release-details/altimmune-receives-fda-breakthrough-therapy-designation
8. Altimmune. EASL 2026 press release, May 28, 2026, and Q1 2026 update. https://altimmune.gcs-web.com/news-releases/news-release-details/pemvidutide-demonstrates-significant-metabolic-improvements ; https://ir.altimmune.com/news-releases/news-release-details/altimmune-announces-first-quarter-2026-financial-results-and
9. ClinicalTrials.gov. NCT07795164, NCT06987513, NCT07009860.
10. WADA. World Anti-Doping Code International Standard: Prohibited List 2026 (in force Jan 1, 2026). https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf (text read Oct 24, 2026)

Disclaimer

This page is for education and harm reduction. It is not medical advice and not a recommendation to use pemvidutide. Please talk to a clinician you trust before making medical decisions, seek care right away for severe stomach pain or repeated vomiting, and report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).

Approved for Adam Greene by Dr. Nova Reyes, 2026-10-25.