Peptides / Recovery and repair

Synthetic analog · 27 amino acids · 2,986.5 Da

B7-33 (single-chain relaxin-2 analog)

B7-33 is a lab-made, single-chain version of the hormone relaxin-2, and no approval as a drug was found. It has been tested only in animal and lab studies, mostly on fibrosis and heart function. PepBank shows 31 results on B7-33 from animal and lab studies. No study in people has reported results yet. Data as of 2026-10-30.

Also known as B7-33, B7-33 C11.23S, Single-chain relaxin-2 analog B7-33

27 amino acids, from first to last3 changed amino acids

Evidence level: Animal and lab studies onlyNo study in people has results. ClinicalTrials.gov lists no trial.

Results in people

0% of 31 results

Results in animals

74% of 31 results

Results in lab cells

26% of 31 results

From computer models

0% of 31 results

Overview

B7-33 (single-chain relaxin-2 analog) at a glance

What it is	Synthetic analog, 27 amino acids
Approval	Regulatory status not recorded
In sport	Status unknown
Studies	8 studies with results. All of them gave B7-33, with 31 results. 23 in animals8 in lab cells
Clinical trials	None registered
Community use	Experimental fibrosis and repair interest

The science

What is B7-33?

A single-chain relaxin-2 analog studied in preclinical fibrosis and repair models.

Amino acids in one chain

B7-33 (single-chain relaxin-2 analog) structure and chemistry

The key facts about the molecule. Long codes are in the closed section below.

Sequence, 27 amino acidsFrom the first amino acid to the last

V1I+KLS5G+R−ELV10+RAQIA15ISGMS20TWS+K+R25SL

Darker means more water-repelling+ and − show charge in the bodyOutlined: changed amino acid

Structure

B7-33 (single-chain relaxin-2 analog) is a synthetic analog of 27 amino acids, with no ring, 3 changed amino acids.

Formula

C₁₃₁H₂₂₉N₄₁O₃₆S

Molecular weight

2,986.5 g/mol

Target

Relaxin family peptide receptor 1 (gene RXFP1): agonistEvidence: primary design paper

Development

Highest phase: preclinical.

Identifiers

PubChem 162662592

Full sequence, SMILES and InChIKey

InChIKey
UAGASAJLEJWQIF-GARFIVTISA-N

SMILES
CC[C@H](C)[C@@H](C(=O)N[C@@H](CO)C(=O)NCC(=O)N[C@@H](CCSC)C(=O)N[C@@H](CO)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC1=CNC2=CC=CC=C21)C(=O)N[C@@H](CO)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC(C)C)C(=O)N)NC(=O)[C@H](C)NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](CCC(=O)N)NC(=O)[C@H](C)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@H](CCCNC(=N)N)NC(=O)CNC(=O)[C@H](CO)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](C(C)C)N

See charge, composition and 3D structure on the Scientific page

The evidence

What B7-33 studies show

Results grouped by what the studies measured. Each card shows where its results come from.

Animal and lab studies onlyNo study in people has results. ClinicalTrials.gov lists no trial.

Heart and blood vessels

14 results · 12 animal · 2 lab

In rats, B7‑33 increased bradykinin-mediated mesenteric artery relaxation compared with placebo through increased endothelium-derived hyperpolarization. European journal of pharmacology, 2017

Top results

In rats, B7‑33 increased bradykinin-mediated mesenteric artery relaxation compared with placebo through increased endothelium-derived hyperpolarization. (European journal of pharmacology, 2017)
In mice with heart ischemia-reperfusion injury, B7‑33 reduced infarct size compared with vehicle. (Journal of the American Heart Association, 2020)
In mice with cardiomyopathy, B7‑33 and relaxin reduced heart fibrosis to a similar extent. (Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2023)

Pain

2 results · 2 animal

In mice with paw inflammation, B7‑33 briefly reduced mechanical sensitivity only in the inflamed paw at 30 minutes. Pain reports, 2021

Top results

In mice with paw inflammation, B7‑33 briefly reduced mechanical sensitivity only in the inflamed paw at 30 minutes. (Pain reports, 2021)
In mice with paw inflammation, B7‑33 briefly reduced heat sensitivity only in the inflamed paw at 30 minutes. (Pain reports, 2021)

Cancer

1 result · 1 animal

In animals, B7‑33 did not promote prostate tumor growth, in contrast to H2 relaxin. Chemical science, 2016

Top results

In animals, B7‑33 did not promote prostate tumor growth, in contrast to H2 relaxin. (Chemical science, 2016)

Immune system and inflammation

1 result · 1 animal

In mice with cardiomyopathy, B7‑33 normalized injury-related heart inflammation. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2023

Top results

In mice with cardiomyopathy, B7‑33 normalized injury-related heart inflammation. (Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2023)

Lungs and breathing

1 result · 1 animal

In rodents with heart or lung disease, B7‑33 prevented or reversed organ scarring with potency similar to H2 relaxin. Chemical science, 2016

Top results

In rodents with heart or lung disease, B7‑33 prevented or reversed organ scarring with potency similar to H2 relaxin. (Chemical science, 2016)

Overall treatment results

1 result · 1 animal

In rodents with heart or lung disease, B7‑33 prevented or reversed organ dysfunction with potency similar to H2 relaxin. Chemical science, 2016

Top results

In rodents with heart or lung disease, B7‑33 prevented or reversed organ dysfunction with potency similar to H2 relaxin. (Chemical science, 2016)

All 8 B7-33 studies by area Open the Scientific page

Key B7-33 studies

Studies in people come first, then studies in animals and in the lab.

Animals
A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor, RXFP1
Hossain et al. 2016 · Chemical science · cited by 63
7 results
Animals
B7-33 replicates the vasoprotective functions of human relaxin-2 (serelaxin)
Marshall et al. 2017 · European journal of pharmacology · cited by 29
4 results
Animals
Assessment of renal fibrosis and anti-fibrotic agents using a novel diagnostic and stain-free second-harmonic generation platform
Bhuiyan et al. 2021 · FASEB journal : official publication of the Federation of American Societies for Experimental Biology · cited by 20
2 results
Animals
B7-33, a Functionally Selective Relaxin Receptor 1 Agonist, Attenuates Myocardial Infarction-Related Adverse Cardiac Remodeling in Mice
Devarakonda et al. 2020 · Journal of the American Heart Association · cited by 17
6 results
Animals
The single-chain relaxin mimetic, B7-33, maintains the cardioprotective effects of relaxin and more rapidly reduces left ventricular fibrosis compared to perindopril in an experimental model of cardiomyopathy
Alam et al. 2023 · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · cited by 12
7 results

All 8 B7-33 (single-chain relaxin-2 analog) studies

B7-33 clinical trials

ClinicalTrials.gov lists no trial of B7-33. A trial under another name may exist.

Status and safety

Is B7-33 approved?

FDA

United States

Status unknown

Status unknown.

EMA

European Union

Status unknown

Status unknown.

WADA

Sport

Not recorded

Status unknown.

Regulatory status not recorded. Status unknown.

Laws and labels change, so check the regulator for the current status.

B7-33 side effects and safety

PepBank has 1 safety result from studies of B7-33. None of them come from studies in people, so they do not show what happens in people.

Safety results from studies (1)

In animals, B7‑33 did not promote prostate tumor growth, in contrast to H2 relaxin. (Chemical science, 2016)

See every safety result on the Scientific page

Doses studied (6 shown)

The doses that these studies used. They are not recommendations.

Dose as reported	Class	Species	Route	Duration	Design	Source
13.3μg/kg	Animal	rat	intravenous	Not reported	Study in live animals	Marshall 2017
0.25 mg/kg/day	Animal	mouse	Not reported	7 days	Study in live animals	Bhuiyan 2021
0.25 mg/kg/day	Animal	mouse	subcutaneous	days 7-14 post-injury	Study in live animals	Alam 2023
15, 30nM	Lab	mouse	Not reported	Not reported	Study on tissue taken from a body	Marshall 2017
50 and 100 nmol/L	Lab	Not reported	Not reported	Not reported	Study on cells in a dish	Devarakonda 2020
100 nmol/L	Lab	Not reported	Not reported	Not reported	Study on cells in a dish	Devarakonda 2020

From the community

How people use it

What people report online. It comes from forums and guides, not from studies.

Community-reported. Not tested in trials.

The source reports interest in this product. Its statements do not establish clinical benefit or a safe regimen.

Reported routines and cautions

What people use it for

Experimental fibrosis and repair interestS1

Reported regimens

Regimens that community sources report for B7-33. Community-reported, not tested in trials.
Context	Route	Amount	How often	How long	Agreement	Sources
Guide reports experimental fibrosis and repair use	subcutaneous injection	500 mcg per dose	once daily	Not stated	Single guide. The page links to an external community with a referral parameter. No peptide seller link was found.	S1

Cautions

The source states that published human clinical dosing and safety data do not exist. Its amounts are anecdotal.S1

Community sources

S1B7-33 source guideonepin.appcarries seller links, not linked

Gaps

Underlying user reports were not independently checked. The guide is not human evidence. Its 25-residue and no-methionine claims conflict with the defined structure. Source statements do not establish safety, efficacy, or an approved dose. The referral link does not establish affiliate compensation.

Questions and more

Ask a question about B7-33

The answer links to every study it uses.

What does the evidence say about B7-33?Is B7-33 tested in people?Compare with Thymosin beta-4 (human)Compare with BPC-157

Sources

Database: PepBank data for B7-33 (data version 308560)
Regulator: WADA status record
Community: community sources (forums and guides), as summarized in the PepBank community file

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

PepBank is a research reference. Talk to a doctor before you use any peptide.

Ask your AI about B7-33

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B7-33 (single-chain relaxin-2 analog)

Also known as B7-33, B7-33 C11.23S, Single-chain relaxin-2 analog B7-33

What it is

Synthetic analog, 27 amino acids

Approval

Regulatory status not recorded

In sport

Status unknown

Studies

8 studies with results. All of them gave B7-33, with 31 results.
23 in animals8 in lab cells

Clinical trials

None registered

Community use

Experimental fibrosis and repair interest

Dose as reported

Class

Species

Route

Duration

Design

Source

13.3μg/kg

Animal

rat

intravenous

Not reported

Study in live animals

Marshall 2017

0.25 mg/kg/day

Animal

mouse

Not reported

7 days

Study in live animals

Bhuiyan 2021

0.25 mg/kg/day

Animal

mouse

subcutaneous

days 7-14 post-injury

Study in live animals

Alam 2023

15, 30nM

Lab

mouse

Not reported

Study on tissue taken from a body

Marshall 2017

50 and 100 nmol/L

Lab

Not reported

Study on cells in a dish

Devarakonda 2020

100 nmol/L

Lab

Not reported

Study on cells in a dish

Devarakonda 2020

Context

Route

Amount

How often

How long

Agreement

Sources

Guide reports experimental fibrosis and repair use

subcutaneous injection

500 mcg per dose

once daily

Not stated

Single guide. The page links to an external community with a referral parameter. No peptide seller link was found.

B7-33 (single-chain relaxin-2 analog)

B7-33 (single-chain relaxin-2 analog) at a glance

What is B7-33?

B7-33 (single-chain relaxin-2 analog) structure and chemistry