MET-233i dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
MET-233i is Pfizer's monthly amylin shot, from Metsera. It stays in the body about 19 days. It is being mixed with berobenatide into one monthly GLP-1 and amylin shot.
Evidence grade for MET-233i: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 1 completed trial, none stating how many people. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 1
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 0 people given it
1 effects reported, 1 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
MET-233i is a monthly shot that copies amylin, a hormone that makes you feel full. Pfizer got it from Metsera. It is being paired with berobenatide, a monthly GLP-1 shot. It is at an early stage and not approved.
What people take it for
- One shot a month for weight loss.
- A monthly take on the CagriSema idea.
What studies in people showed
In the first study in people, the company says the best dose took off up to 8.4 percent more weight than a dummy shot by day 36. The body took 19 days to clear half of it. That is why a monthly shot looks possible. This came from a company release about an early safety study, not a paper.
What people report
Reports, not study results
The good
- In the company report on this page, weight came off within five weeks.
The bad
- The report on this page does not list side effects, and we have not collected user reports on this one yet.
Where these come from: The good line is from the company release on this page. We have not collected forum or user reports for this drug yet.
My bottom line
Five weeks of company numbers is a teaser, not proof. Nothing to buy and nothing to do yet.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals MET-233i has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Losing weightno headcount stated · 1 study
35 of the 36 indexed goals have no study of any kind behind MET-233i
No study in people, animals or cells on this page reports a result for these. That does not prove MET-233i does nothing for them. It does mean anything you have heard about MET-233i and one of these did not come from a study cited here.
Show full evidence
What is MET-233i?
MET-233i is Pfizer's monthly amylin shot, from Metsera. It stays in the body about 19 days. It is being mixed with berobenatide into one monthly GLP-1 and amylin shot.
MET-233i is an experimental amylin drug. Amylin is a hormone that makes you feel full. It uses the same long-lasting design as berobenatide, and it is meant to be given once a month, alone or with a GLP-1 drug. In the first study in people, the company reports up to 8.4 percent more weight loss than a dummy shot by day 36. The body took 19 days to clear half of it. Those numbers come from a company announcement, not a published paper. Pfizer's early 2026 pipeline list shows the pair with berobenatide in a mid-stage study. If it works, it would be a monthly version of the CagriSema idea. It is an early experimental drug and is not available.
How does MET-233i work?
It turns on amylin receptors for a very long time. It is built for monthly shots, alone or with a GLP-1 drug.
The evidence, in charts
Fig. 1a · how many people
1study in people cited, but none says how many people took part
number of people not stated
We do not draw a total, because none of the studies in people on this page gives one. Read the sources below for what each study measured.
We read the number of people from the source lines on this page. Where a line gives no number, we count nothing for it. We do not guess.
Fig. 1b · evidence mix
1 of 2 sources here is a study in people. The rest is not.
- Study in people · done in people150%
- Review of studies · sums up other studies150%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
Sources here come from just two years, 2025 and 2026.
Too few different years on this page to draw a timeline.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Peptide
- Molecule weight
- Not disclosed
- Half-life
- About 19 daysVery long, weeks+
- Chain length
- None on file
No amino acid sequence is on file for MET-233i, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2025Metsera announces positive Phase 1 data of first-in-class once-monthly amylin candidate MET-233i
An early study hints that one injection a month could be enough. In the first test in people, the best dose took off about 8% more body weight than a dummy injection in five weeks, and the body took 19 days to clear half of it. That clearance time is what makes monthly dosing plausible. Here is the problem. This is a company announcement about a first-stage safety study, and studies at that stage are not built to measure weight loss.
Up to 8.4% mean placebo-subtracted weight loss at day 36 and a 19-day observed half-life, which the company says supports once-monthly dosing. Company topline, not a peer-reviewed publication.
- Review of studies2026Pfizer pipeline update, Q1 2026
This is Pfizer's list of drugs in development, not a study. It shows MET-233i paired with berobenatide in a mid-stage study.
MET-233i plus berobenatide combination listed in Phase 2.
Where to buy MET-233i
No seller we track lists MET-233i yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has MET-233i been tested in people?
Yes. 0 people given it across 1 completed trial cited here, 0 of which found nothing. MET-233i is Pfizer's monthly amylin shot, from Metsera. It stays in the body about 19 days. It is being mixed with berobenatide into one monthly GLP-1 and amylin shot.
What is the MET-233i dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 1 completed trial, 0 people given it
Is MET-233i FDA-approved?
Investigational; in mid-stage studies (as a combination)
Is MET-233i available?
No. It is an early experimental drug.