B7-33 dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
B7-33 is a simpler, lab-made version of the hormone relaxin. It switches on relaxin's receptor in a way that leans toward fighting scar tissue. There are only animal and cell data.
Evidence grade for B7-33: Animal or lab only. The rule: only animal or lab studies on this page. No study in people yet. The sum on this page: 2 animal studies, no human study. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
2 animal studies, no human study
3 effects reported, 2 unwanted, 1 wanted, by people using it, not a trial
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.
B7-33 is a simpler, lab-made version of the hormone relaxin. It is built to fight scar tissue. It has only been tested in animals and cells. Nobody has tried it in a person.
What people take it for
- Softening scars.
- Reducing scarring inside organs.
What studies in people showed
There are no human studies. In animal models of heart and lung scarring, it copied relaxin's anti-scarring effects. Implants coated with it formed less scar tissue around them.
What people report
Reports, not study results
The good
- Nobody in the forums describes using it. The one request for a human dose got no replies.
The bad
- The doses that circulate are rodent amounts with no attempt to convert them for people.
- No complaints only means no users. It is not a safety record.
Where these come from: One LongeCity thread and one ExcelMale reference list, as summed up on this page, plus the animal studies on this page.
My bottom line
Promising in animals, untested in people. Not something I would inject.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
What people using it report
Real people telling you what happened to them. Nobody checked it, and the people who post are not a fair sample, so it cannot prove anything works. It is still the best guide on this page to what people actually do with B7-33, what they expect, and what goes wrong. The full account, including the negative reports, is below.
Nothing indexed yet
The 2 citations on this page do not report a result for any of the 36 goals indexed here. Most of what sits here is something else: a listing of a planned study, a study of how the body handles the drug, a safety report or a government record. None of those tests whether it works.
Show full evidence
What is B7-33?
B7-33 is a simpler, lab-made version of the hormone relaxin. It switches on relaxin's receptor in a way that leans toward fighting scar tissue. There are only animal and cell data.
Relaxin is a hormone that fights scar tissue, but it is hard to make. B7-33 was designed to get around that. It is a one-chain version that switches on relaxin's receptor, RXFP1, but leans toward the anti-scarring signal. It avoids the signal that wears the receptor out. In animal models of heart and lung scarring, it copied relaxin's anti-scarring effects. Coating implants with it cut the scar capsule that forms around them. All of that is animal and cell work. There are no human trials, so using it for scars or organ scarring in people is untested. It is not approved.
How does B7-33 work?
It switches on the relaxin receptor, RXFP1, in a way that favors the anti-scarring signal inside the cell.
What do people who took B7-33 report?
This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.
- There is effectively no community experience to summarise. The one discussion found is a request for any idea of a human amount, and it drew no replies at all.
- The person asking observed that nothing exists online for human use, which stands in contrast with other experimental compounds where at least folklore protocols circulate freely.
- The figures that do circulate, in peptide reference lists rather than in experience threads, are animal per kilogram amounts lifted from rodent studies and presented without any attempt at human translation.
- Because nobody describes using it, there are no side effect reports, no timelines and no reports of it doing nothing either. An absence of complaints here reflects an absence of users rather than any safety record.
Sources: A LongeCity dosing thread and an ExcelMale peptide reference list, found by site-restricted search and read directly, September 2026. Nothing above is attributed to any specific post and no post is reproduced.
The evidence, in charts
Fig. 1a · how many people
0people have taken this in any study cited here
0 people · 0 studies in people
What this page cites instead is 2 animal studies. None of them gave the compound to a person.
Counted from the list of sources on this page. We draw this chart only when a study in people is cited. An empty one is the answer, not a gap in the page.
Fig. 1b · evidence mix
None of the 2 sources here are studies in people.
- Animal study · done in animals2100%
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, 2016 and 2019.
Too few different years on this page to draw a timeline. The newest source on file is from 2019, more than five years ago. Research on it may have gone quiet.
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 verified (33 amino acid single-chain relaxin analog)
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
No amino acid sequence is on file for B7-33, so none is drawn rather than guessed from a name.
The studies we cite
- Animal study2016A single-chain derivative of the relaxin hormone is a functionally selective agonist of RXFP1
In animals. It fought organ scarring.
Anti-fibrotic effects in animal models.
- Animal study2019Coatings Releasing the Relaxin Peptide Analogue B7-33 Reduce Fibrotic Encapsulation
In animals. Implants coated with it formed less scar tissue around them.
Reduced fibrotic capsule formation.
Where to buy B7-33
18 sellers list B7-33 in our latest read. They are ranked by trust score, then by archive rating, then by certificate tier, then by the lowest price per milligram. Archive evidence is counted before source-backed. Each path is out of 4, and the two are not added. A higher price does not raise the score. The letter is the certificate chip. 1 of them has a published certificate that names B7-33.
Some seller links may pay this site when you buy through them. A payment never changes a seller's tier or rank, and no seller has a say in any page.
| Seller | Trust score | Vial sizes | From, per mg | Certificate for B7-33 | Seller link |
|---|---|---|---|---|---|
| National Science Labs | 80 StrongSource-backed 4 of 4. Archive evidence 2 of 4.A | 2 mg, 10 mg | $6.20 | None found for B7-33 | View |
| Core Peptides | 75 StrongSource-backed 4 of 4. Archive evidence 2 of 4.A | 6 mg | $10.0 | None found for B7-33 | View |
| Limitless Bio-Tech | 52 FairSource-backed 1 of 4. Archive evidence 1 of 4.C | 10 mg | $4.28 | None found for B7-33 | View |
| Biotech Peptides | 49 WeakSource-backed 3 of 4. Archive evidence 3 of 4.A | 6 mg | $10.3 | Certificate, MZ Biolabs | View |
| Core Peptides Official | 49 WeakSource-backed 3 of 4. Archive evidence 2 of 4.A | 6 mg | $9.33 | None found for B7-33 | View |
| Peptide Shop A | 49 WeakSource-backed 2 of 4. Archive evidence 2 of 4.B | 6 mg | $10.3 | None found for B7-33 | View |
| Behemoth Labz | 49 WeakSource-backed 3 of 4. Archive evidence 1 of 4.B | 6 mg, 12 mg | $10.7 | None found for B7-33 | View |
| Pure Peptide Factory | 48 WeakSource-backed 1 of 4. Archive evidence 1 of 4.C | 2 mg, 10 mg | $9.00 | None found for B7-33 | View |
| USA Peptide Science Shop | 45 WeakSource-backed 2 of 4. Archive evidence 1 of 4.B | 6 mg | $11.7 | None found for B7-33 | View |
| Peptide Works | 43 WeakSource-backed 2 of 4. Archive evidence 1 of 4.B | 2 mg, 6 mg | $9.72 | None found for B7-33 | View |
| Direct SARMS | 40 WeakSource-backed 1 of 4. Archive evidence 1 of 4.C | 2 mg, 6 mg | $9.67 | None found for B7-33 | View |
| Limitless Biotech ST | 36 WeakSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $10.0 | None found for B7-33 | View |
| Lejian Biotech Peptide | 35 WeakSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $8.33 | None found for B7-33 | View |
| Huaian Hanyou Peptide | 25 InsufficientSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $8.33 | None found for B7-33 | View |
| MJA Peptides | 25 InsufficientSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $8.33 | None found for B7-33 | View |
| ZL Peptides | 25 InsufficientSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $8.33 | None found for B7-33 | View |
| Peptide Science LLC | 25 InsufficientSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $11.7 | None found for B7-33 | View |
| USA Peptide Sciences | 25 InsufficientSource-backed 1 of 4. Archive evidence 1 of 4.C | 6 mg | $11.7 | None found for B7-33 | View |
- LC Lab-confirmed: the issuing laboratory echoed this certificate back
- A Current certificate, independent laboratory named, laboratory not yet checked
- B Certificate published, but no laboratory link, older than a year, or the laboratory did not recognise the published lookup
- C No certificate could be read
Every listing and vial size for B7-33 · How the trust score is counted
Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything.
Common questions
Has B7-33 been tested in people?
Not in any study cited here. B7-33 is a simpler, lab-made version of the hormone relaxin. It switches on relaxin's receptor in a way that leans toward fighting scar tissue. There are only animal and cell data.
What is the B7-33 dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 2 animal studies, no human study
Is B7-33 FDA-approved?
Not approved
Can B7-33 soften scars?
Nobody has tested it in people. Its evidence comes from animal models of scarring.