Berobenatide_Dosage, benefits & legal status
Also known as MET-097i, MET-097, PF-08653944, PF'3944
An experimental GLP-1 shot built to be given monthly, now in Pfizer's phase 3 programme.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Berobenatide?
Plain language first. The technical label stays, but it never stands alone.Overview
It works like semaglutide but stays in the blood long enough (a half-life of about 16 days) for the company to test a monthly maintenance dose. Phase 2b trials reported up to 14% placebo-adjusted weight loss at 28 weeks, and phase 3 began in December 2025. It is not approved anywhere.
What it's used for
An experimental GLP-1 shot for weight loss, tested weekly and then monthly. The top weekly phase 2b dose gave 14.1% placebo-adjusted weight loss at 28 weeks.
How does Berobenatide work?
What it does in the body, and where.Berobenatide is a 41-residue peptide built on exendin-4, the lizard-venom GLP-1 mimic behind exenatide, with a fatty tail that keeps it in the blood for weeks.
- 01GLP-1 receptorSlows stomach emptying, blunts appetite and raises insulin after meals. This is the same receptor semaglutide works.
- 02Biased signallingIn cell assays it fully switched on the receptor's cAMP signal while recruiting little or no beta-arrestin. Metsera argues this means fewer receptors are pulled into the cell; no trial has shown that this changes outcomes.
- 03Albumin anchorA 20-carbon fatty diacid on the last lysine binds albumin. The human half-life is about 380 hours, long enough to test a monthly shot.
Acts on one receptor.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
Weekly dosing
Investigational- Human trialVESPER-1, 239 adults with obesity, 28 weeks without a ramp-up: placebo-adjusted weight loss of 8.1% on 0.4 mg rising to 14.1% on 1.2 mg weekly.
- Human trialIn the extension, people switched from placebo to 2.4 mg weekly lost 15.9% over 32 weeks. This is an unadjusted average with no placebo group for comparison.
- No dataMetsera's September 2025 table listed 54 people per VESPER-1 arm. The registry shows 47 to 48, with the same placebo-adjusted results; 54 per arm matches VESPER-3.
Monthly dosing
Investigational- Human trialVESPER-3, 268 adults: after 12 weekly doses, people switched to monthly doses. At week 28, placebo-adjusted loss was 10.0% on 3.2 mg monthly and 12.3% on 4.8 mg monthly (efficacy estimand), or 8.4% and 10.5% counting everyone as randomised.
- No dataResults for the other two VESPER-3 arms and the absolute weight changes have not been released.
Type 2 diabetes
Investigational- Human trialVESPER-2, 133 adults with obesity and type 2 diabetes, 28 weeks: HbA1c fell 2.2 points on 1.6 mg weekly against 0.2 on placebo.
- No dataWeight results were described only as dose-dependent; no figures have been released.
The 12.3% figure is placebo-adjusted, on the efficacy estimand, at week 28, for the 4.8 mg monthly arm only; counting everyone as randomised it is 10.5%. The 14.1% VESPER-1 figure is also placebo-adjusted: the absolute loss on 1.2 mg was 12.45%, because the placebo group gained weight. The 15.9% figure is an unadjusted average in former placebo patients after 32 weeks on 2.4 mg weekly, not a monthly-dosing result. A 19-day half-life quoted for it belongs to its amylin partner PF-08653945; berobenatide's is about 380 hours. PF-08653944 and PF-08653945 differ by one digit and are different drugs.
The published record
Papers and trials about Berobenatide
18 papers tagged human · 0 not reviews or lab · 0 clinical trial publications
18 registered trials · 1 with posted results
Furthest stage reached: Phase 3, under way
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Berobenatide
Evidence
Investigational
Category
Weight loss and metabolic
Common vial
Varies
Half-life
About 16 days
How much, and do you cycle it?
The range, and whether you take breaks.0.4 up to 2.4 mg weekly, or 3.2 to 4.8 mg monthly (trial doses), weekly, then monthly in some trials. Not cycled in the trials Trial dose
Given without a break for 28 to 64 weeks in phase 2 and up to 72 weeks in phase 3. The weekly-to-monthly switch changes the schedule; it is not a pause.
How long does it stay in the body?
The half-life, and where the figure comes from.About 16 daysTrial protocol
From the company's first-in-human study; no peer-reviewed PK paper has been published. In pigs the half-life was 99 hours.
Source: Metsera Form 10-K for 2024, single ascending dose study (about 380 hours, dose-proportional)
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized Berobenatide keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 39% charged residues, 34% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- A personal or family history of medullary thyroid cancer or MEN 2, excluded from its trials as for every GLP-1 drug
- A history of pancreatitis, also excluded
- Reduced kidney function: the phase 2 trials excluded an eGFR below 75
- Active gallbladder disease, excluded from the phase 3
- Pregnancy or breastfeeding
Stop and get help
- Severe stomach pain spreading to your back, a possible sign of pancreatitis (one case was reported in phase 2b)
- Vomiting badly enough that you cannot keep fluids down
- Pain under the right ribs with fever or yellowing skin
- Spreading hives, swelling of the face or throat, or trouble breathing
Common effects
- Nausea in 31 to 50% across weekly doses of 0.4 to 1.2 mg over 28 weeks, against 27% on placebo
- Vomiting in 17 to 28%, against 13% on placebo
- Diarrhoea in 10 to 23% (placebo 10%) and constipation in 8 to 23% (placebo 17%)
- Without a ramp-up, 65% had nausea and 60% vomiting on 1.2 mg in phase 1; a two-step ramp cut those to 5% and 10%
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Berobenatide approved?
And where the numbers on this page come from.No. Berobenatide is not approved anywhere and is currently in company-run clinical trials. There is no legal route to obtain it outside a trial.
- Approval statusInvestigational
- RouteUnder the skin (subcutaneous)
- Checked11 October 2026
- DoseFrom published clinical trials. Not approved by a regulator for this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesFDA GSRS substance record, berobenatide (UNII UN3RWY4TEG)ClinicalTrials.gov, VESPER-1 posted results (NCT06712836)ClinicalTrials.gov, VESPER-3 (NCT06973720)Pfizer, VESPER-3 28-week results (3 Feb 2026)Pfizer, ADA 2026 release (6 Jun 2026)Metsera, Form 10-K for 2024ClinicalTrials.gov, VESPER-4 phase 3 (NCT07311850)Metsera, Form 8-K, amended merger agreement with Pfizer (7 Nov 2025)
What has happened recently
Not approved anywhere. Phase 3 began on 19 December 2025 with VESPER-4 (3,578 people without diabetes, weekly dosing), followed by VESPER-5 in type 2 diabetes and VESPER-6 testing monthly dosing; further phase 3 trials are registered for China and Japan. Pfizer completed its purchase of Metsera on 13 November 2025, after raising its offer when Novo Nordisk made a competing proposal. The name berobenatide was proposed on WHO INN list 133; its recommended status was not confirmed for this page.
You can compare this against the whole library, or read how to check a seller.
What else is like Berobenatide?
Others in GLP-1 agonists, side by side.If you're weighing Berobenatide, it's worth reading CT-388, Danuglipron, and Dulaglutide (Trulicity) in the same class.
An experimental GLP-1 shot built to be given monthly, now in Pfizer's phase 3 programme.
- Dose
- 0.4 up to 2.4 mg weekly, or 3.2 to 4.8 mg monthly (trial doses)
- How often
- Weekly, then monthly in some trials
An experimental weekly weight-loss shot in the tirzepatide family.
- Dose
- 4 up to 24 mg per week (trial doses)
- How often
- Weekly
An experimental weight-loss pill whose development was stopped over a liver-injury signal.
- Dose
- 40 up to 200 mg per dose
- How often
- Daily
A weekly GLP-1 shot for diabetes, with far less weight loss than the famous ones.
- Dose
- 0.75 up to 4.5 mg per week (start low, increase slowly)
- How often
- Weekly
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- FDA GSRS substance record, berobenatide (UNII UN3RWY4TEG)(2026)41-residue synthetic peptide on an exendin-4 template: Aib at position 2 and a gamma-glutamate plus C20 fatty diacid on lysine 41. Formula C232H369N57O68, MW 5044.8. CAS 3028974-74-2. Source cited: proposed INN list 133.
- ClinicalTrials.gov, VESPER-1 posted results (NCT06712836)(2026)239 randomised, 28 weeks, no titration. LS mean weight change -6.41% to -12.45% across 0.4 to 1.2 mg against +1.67% on placebo; placebo-adjusted -8.09 to -14.13 points (all p<0.0001, efficacy estimand). Nausea 31 to 50% against 27%.
- ClinicalTrials.gov, VESPER-3 (NCT06973720)(2026)268 enrolled. 12 weekly doses with titration, then monthly doses four times the weekly dose (3.2 or 4.8 mg), against placebo, for 64 weeks.
- Pfizer, VESPER-3 28-week results (3 Feb 2026)(2026)Placebo-adjusted weight loss at week 28 of 10.0% (3.2 mg monthly arm) and 12.3% (4.8 mg monthly arm) on the efficacy estimand; 8.4% and 10.5% on treatment-policy. All arms p<0.001. No plateau reported.
- Pfizer, ADA 2026 release (6 Jun 2026)(2026)VESPER-2 in type 2 diabetes: HbA1c down 2.2 points on 1.6 mg weekly against 0.2 on placebo at week 28. Former placebo patients on 2.4 mg weekly lost 15.9% over 32 weeks (unadjusted). Ten phase 3 studies planned for 2026.
- Metsera, Form 10-K for 2024(2025)First-in-human study: dose-proportional PK with a half-life of about 380 hours; placebo-adjusted weight loss 11.3% at day 85 on 1.2 mg weekly. Full cAMP activation with minimal beta-arrestin recruitment in vitro.
- ClinicalTrials.gov, VESPER-4 phase 3 (NCT07311850)(2026)3,578 enrolled without diabetes, three weekly doses against placebo, primary endpoint at week 64. Started 19 December 2025.
- Metsera, Form 8-K, amended merger agreement with Pfizer (7 Nov 2025)(2025)$65.60 cash plus a contingent value right of up to $20.65 per share after a competing Novo Nordisk proposal. One CVR milestone is FDA approval of monthly MET-097i by the end of 2029.
Beyond these, 18 records are indexed. Browse the records