B7-33 (6mg) Research Peptide: A Single‑Chain Relaxin Mimetic for Anti‑Fibrotic, Cardioprotective & Vascular Research

If your research investigates fibrosis, cardiac remodelling, or vascular dysfunction, B7-33 (6mg) research peptide offers a precisely defined and mechanistically distinct synthetic tool. B7‑33 is a single‑chain 27‑amino‑acid peptide analogue derived from the B‑chain of human relaxin‑2 (H2 relaxin). Unlike the complex two‑chain, disulfide‑rich structure of native relaxin, B7‑33 is a linear peptide that is far easier and more cost‑effective to produce.

What makes B7‑33 particularly valuable for research is its functional selectivity: while it binds to the relaxin family peptide receptor 1 (RXFP1)—the cognate receptor for relaxin‑2—it preferentially activates the pERK pathway over the cAMP pathway. This selective signalling profile is thought to preserve the potent anti‑fibrotic, cardioprotective, and vasoprotective effects of relaxin while avoiding pathways that have been associated with tumour‑promoting actions. This makes B7-33 (6mg) research peptide a valuable tool for laboratories investigating fibrosis, cardiac protection, vascular biology, and preeclampsia.

At Chinese Grey Peptides, we supply high‑purity B7-33 (6mg) research peptide to research institutions and wholesale buyers across the United Kingdom, France, Germany, Spain, Sweden, Italy, and the USA. Every batch is lyophilised, HPLC‑verified to ≥98% purity, and accompanied by a Certificate of Analysis (COA), ensuring your investigations into fibrosis, cardiac remodelling, and vascular biology begin with uncompromising quality.

What Is B7‑33 and How Does It Work?

To fully appreciate the research potential of B7‑33 (6mg) research peptide, it is essential to understand its biochemical design and the precise mechanism by which it exerts its effects.

The 27‑Amino‑Acid Single‑Chain Peptide

B7‑33 is a synthetic linear peptide composed of 27 amino acids. Its sequence is Val‑Ile‑Lys‑Leu‑Ser‑Gly‑Arg‑Glu‑Leu‑Val‑Arg‑Ala‑Gln‑Ile‑Ala‑Ile‑Ser‑Gly‑Met‑Ser‑Thr‑Trp‑Ser‑Lys‑Arg‑Ser‑Leu‑NH₂ (VIKLSGRELVRAQIAISGMSTWSKRSL‑NH₂). Its molecular formula is C₁₃₁H₂₂₉N₄₁O₃₆S with a molecular weight of approximately 2,986.54‑2,987.52 g/mol. It has a CAS number of 1818415‑56‑3.

The peptide consists of residues 7‑29 of the B‑chain of H2 relaxin, with the addition of a KRSL sequence that dramatically improves solubility. Unlike native relaxin, B7‑33 is a single‑chain linear peptide without the complex disulfide‑rich structure of the native hormone.

Mechanism of Action: Functional Selectivity at RXFP1

The biological activity of B7-33 (6mg) research peptide is mediated through its selective activation of the relaxin family peptide receptor 1 (RXFP1):

• RXFP1 Binding and Functional Selectivity: B7‑33 binds to RXFP1—the cognate receptor for relaxin‑2. However, unlike native relaxin, which strongly activates both the cAMP and pERK pathways, B7‑33 preferentially activates the pERK pathway over cAMP. This makes B7‑33 the first functionally selective agonist of the complex GPCR RXFP1.

• Anti‑Fibrotic Signalling via RXFP1‑AT₂R Heterodimers: The strong anti‑fibrotic actions of B7‑33 involve its activation of RXFP1‑angiotensin II type 2 receptor (AT₂R) heterodimers. This induces selective downstream signalling of pERK1/2 and the collagen‑degrading enzyme matrix metalloproteinase‑2 (MMP‑2).

• Inhibition of TGF‑β1 Signalling: B7‑33 modulates pro‑fibrotic signalling pathways, including downregulation of Collagen Type I α‑1 Chain (COL1A1) expression.

• Cardioprotection via ERK1/2‑Dependent Pathways: B7‑33 confers cardioprotection by attenuating cardiomyocyte death and endoplasmic reticulum stress through ERK1/2‑dependent mechanisms.

Research Note: Avoiding the Tumour‑Promoting Pathway

A key advantage of B7‑33 for research is that, in contrast to H2 relaxin, B7‑33 did not promote prostate tumour growth in vivo, likely because it does not strongly activate the cAMP pathway. This functional selectivity allows researchers to study the beneficial anti‑fibrotic and cardioprotective effects of relaxin receptor activation without the confounding variable of tumour‑promoting signalling.

Key Research Applications for B7-33 (6mg)

B7-33 (6mg) research peptide is a versatile tool with applications spanning several domains of biomedical research.

1. Fibrosis & Scarring Research

B7‑33 has demonstrated potent anti‑fibrotic effects in multiple preclinical models. Research applications include:

• Hypertrophic Scarring: B7‑33 modulates fibrotic signalling in human hypertrophic scar fibroblasts, significantly modulating pro‑fibrotic gene expression and downregulating COL1A1.

• Organ Fibrosis: B7‑33 has been shown to prevent or reverse organ fibrosis and dysfunction in three pre‑clinical rodent models of heart or lung disease.

• Myocardial Infarction Scarring: B7‑33 significantly reduced infarct size (21.99% versus 45.32%; P=0.02) and preserved cardiac function in a mouse model of myocardial infarction.

• Surgical Mesh Fibrosis: B7‑33 is being investigated as an anti‑fibrotic coating for surgical meshes to mitigate fibrotic encapsulation.

2. Cardiovascular & Cardiac Research

B7‑33 has demonstrated significant cardioprotective effects. Research has shown:

• Cardioprotection Post‑Infarction: B7‑33 confers acute cardioprotection and limits myocardial infarction‑related adverse cardiac remodelling in mice.

• Reduction of Left Ventricular Fibrosis: In an isoprenaline‑induced cardiomyopathy model, B7‑33 reduced left ventricular fibrosis and normalised inflammation and cardiomyocyte hypertrophy.

• Cardiomyocyte Protection: B7‑33 (50 and 100 nmol/L) improved cell survival and reduced endoplasmic reticulum stress markers in primary cardiomyocytes subjected to simulated ischaemia‑reperfusion injury.

3. Preeclampsia & Vascular Research

B7‑33 has been studied for its effects in preeclampsia models:

• Preeclampsia Attenuation: B7‑33 demonstrates efficacy in attenuating the symptoms of preeclampsia, including hypertension and inflammation.

• Vasoprotection: B7‑33 replicates the vasoprotective functions of human relaxin‑2 (serelaxin), preventing endothelial dysfunction.

4. Drug Delivery & Biomaterial Research

B7‑33 is being investigated in advanced delivery systems:

• Controlled Release Dressings: Electrospun B7‑33‑loaded dressings enable controlled release over 72 hours (96 ± 3.1%), with the peptide retaining antifibrotic activity after incorporation.

• Biodegradable Coatings: Poly(lactic‑co‑glycolic) acid (PLGA) coatings releasing B7‑33 have been shown to reduce fibrotic encapsulation.

• Oral Delivery: Tiny biodegradable nanoparticles can safely carry anti‑fibrotic peptides, including B7‑33, through the gut and into the bloodstream.

5. Pain & Analgesia Research

Both H2‑relaxin and B7‑33 produced a strong, but transient, reduction in mechanical and thermal sensitivity, identifying a previously unexplored peptidergic system that can control pain processing in the brain.

Chemical & Physical Specifications for B7-33 (6mg)

Accurate characterisation of B7-33 (6mg) research peptide is essential for reproducible experimental design.

Note: The 6 mg mass refers to the weight of the peptide in its lyophilised form. B7‑33 is a single‑chain linear peptide, unlike the complex two‑chain, disulfide‑rich structure of native relaxin. This structural simplicity is a key advantage for research applications.

Reconstitution & Handling Protocol for B7-33 (6mg)

Proper reconstitution of B7‑33 (6mg) research peptide is critical for maintaining its structural integrity and biological activity.

Step 1 – Preparation

• Bring the sealed B7‑33 vial and your chosen diluent (sterile bacteriostatic water or sterile PBS, pH 5‑7) to room temperature. Condensation can degrade the lyophilised powder.

• Clean your work surface with 70% ethanol and lay out sterile syringes, alcohol wipes and a clean work mat.

Step 2 – Vial Sanitisation

• Wipe the rubber stopper of the B7‑33 vial with a fresh 70% ethanol wipe. Allow the alcohol to evaporate completely before piercing.

Step 3 – Reconstitution

• Draw your desired volume of diluent into a sterile syringe. A common starting concentration for research applications is 6 mg per 0.6 mL of diluent, yielding a 10 mg/mL stock solution.

• Insert the needle and slowly inject the diluent against the inner glass wall. Do not spray directly onto the lyophilised powder.

• Gently swirl the vial until the solution is clear and fully dissolved. Do not shake vigorously, as shaking can cause denaturation.

Step 4 – Aliquoting & Storage

• Immediately after dissolution, aliquot the reconstituted B7‑33 into single‑use sterile vials.

• Store aliquots at –20°C. Avoid repeated freeze‑thaw cycles, as peptides are susceptible to degradation.

• Once thawed, store at 2‑8°C and use within a short period.

Concentration Reference Table for B7-33 (6mg)

Adjust diluent volume based on your experimental requirements. For cell culture applications, typical working concentrations may range from 0.1‑10 µM. Preclinical studies have used B7‑33 at 0.25 mg/kg/day and 50‑100 nmol/L in vitro.

Storage & Stability Guidelines for B7-33 (6mg)

Why Choose Chinese Grey Peptides for B7-33 (6mg)?

As an authentic licensed peptide supplier based in the USA, we supply B7-33 (6mg) research peptide and a wide range of research‑grade compounds under rigorous quality assurance protocols, fully aligned with Google’s E‑E‑A‑T standards (Experience, Expertise, Authoritativeness, Trustworthiness).

• Verified Purity: Independent HPLC analysis with purity guaranteed ≥98% for every batch.

• GMP‑Compliant Manufacturing: All peptides are synthesised under strict quality control conditions.

• Full Traceability: Batch‑specific Certificates of Analysis (COA) are available for every order.

• Wholesale Supply: We serve research institutions, laboratories, and wholesale buyers across the UK, EU, and USA with flexible volume pricing and reliable logistics.

• USA‑Based Regulatory Compliance: All products are supplied strictly as research‑grade chemicals for laboratory use only (RUO). B7‑33 is not FDA‑approved for therapeutic use and is supplied for research purposes only.

Researchers across the United States—including those at leading institutions—trust us for fast domestic delivery, transparent documentation and professional technical support.

FAQ: B7-33 (6mg) Research Peptide

What is B7-33 (6mg) research peptide?
B7‑33 is a synthetic 27‑amino‑acid single‑chain peptide analogue derived from the B‑chain of human relaxin‑2 (H2 relaxin). It is a functionally selective agonist of the relaxin family peptide receptor 1 (RXFP1), preferentially activating the pERK pathway over cAMP.

What is the sequence and molecular weight of B7‑33?
The sequence is VIKLSGRELVRAQIAISGMSTWSKRSL‑NH₂. Its molecular formula is C₁₃₁H₂₂₉N₄₁O₃₆S, and its molecular weight is approximately 2,986.54‑2,987.52 g/mol.

 What are the primary research applications for B7‑33?
B7‑33 is used in fibrosis and scarring research (hypertrophic scarring, organ fibrosis, myocardial infarction scarring), cardiovascular and cardiac research (cardioprotection, left ventricular fibrosis reduction), preeclampsia and vascular research, drug delivery and biomaterial research, and pain and analgesia research.

What is the mechanism of action of B7‑33?
B7‑33 binds to RXFP1 and preferentially activates the pERK pathway over cAMP. It activates RXFP1‑AT₂R heterodimers, inducing pERK1/2 and MMP‑2 signalling, and confers cardioprotection via ERK1/2‑dependent mechanisms.

 How does B7‑33 differ from relaxin‑2 in research?
Unlike native relaxin, B7‑33 is a single‑chain linear peptide, making it easier and cheaper to produce. It preferentially activates pERK over cAMP, avoiding pathways associated with tumour promotion. Despite this, it retains the anti‑fibrotic and cardioprotective effects of relaxin.

What purity does your B7‑33 (6mg) meet?
Our B7‑33 is tested to ≥98% purity by HPLC. A Certificate of Analysis (COA) is supplied with every order.

 How should I reconstitute B7‑33 (6mg)?
Reconstitute with sterile bacteriostatic water or sterile PBS (pH 5‑7). Allow the vial to reach room temperature, then slowly inject the diluent against the inner glass wall and swirl gently. Do not shake. A typical starting concentration is 10 mg/mL.

How should I store reconstituted B7‑33?
Reconstituted B7‑33 should be stored at 2‑8°C for short‑term use. For longer storage, aliquot immediately into single‑use vials and store at –20°C for up to 3 months. Avoid repeated freeze‑thaw cycles.

Is B7‑33 research peptide legal to purchase in the USA?
Yes. B7‑33 is a laboratory reagent sold for research use only (RUO). It is fully legal to purchase, possess, and use in the United States for legitimate in‑vitro or in‑vivo scientific research, provided it is not marketed with therapeutic claims. Note: B7‑33 is not FDA‑approved for therapeutic use.

Does Chinese Grey Peptides ship internationally?
Yes. We ship across the UK, Europe (France, Germany, Spain, Sweden, Italy), and the USA from our US warehouse. Wholesale pricing is available for bulk orders.

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• PubMed: B7-33 and RXFP1 research context
• PMC: Long-acting relaxin analogues review
• PMC: B7-33 RXFP1 agonist paper
• FDA Gram Peptides warning letter
• Google Product Structured Data
• Rank Math WooCommerce Product Schema

B7-33 (6mg)

Ships to USA, Canada, UK & Europe

Chinese Grey Peptides supports shipping to the USA, Canada, the United Kingdom, France, Germany, Spain, Sweden, Italy, and Europe where permitted.

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B7-33 (6mg)

Important Compliance Notice

B7-33 6mg may be regulated differently depending on the country, product type, labeling, intended use, buyer type, and destination. Chinese Grey Peptides does not provide medical advice, dosing instructions, injection guidance, fibrosis claims, heart-health claims, vascular claims, organ-health claims, anti-aging claims, recovery claims, performance claims, disease claims, treatment claims, or personal-use recommendations.

Customers are responsible for understanding and following all local laws, import rules, prescription requirements, compounding rules, sport-governing rules, and permitted-use requirements before ordering.

From its innovative design as a single‑chain relaxin mimetic to its well‑characterised role as a functionally selective RXFP1 agonist, B7‑33 (6mg) research peptide provides a precisely defined and mechanistically distinct platform for advanced fibrosis, cardiac, and vascular research.

Its ability to preferentially activate the pERK pathway over cAMP, inhibit TGF‑β1 signalling, reduce infarct size, and attenuate left ventricular fibrosis—supported by peer‑reviewed research published in Chemical Science, the Journal of the American Heart Association, Biomedicine & Pharmacotherapy, and other authoritative journals—makes it a valuable addition to any laboratory investigating fibrosis, cardiac remodelling, vascular dysfunction, or preeclampsia. By choosing high‑purity, lab‑verified B7-33 (6mg) research peptide from Chinese Grey Peptides, you ensure that your research is built on a foundation of quality, reproducibility, and scientific integrity.

Ready to advance your research with B7‑33 (6mg)? Browse our product catalogue, request a wholesale quote, or contact our support team today to discuss your laboratory’s specific needs. Place your order now and receive GMP‑grade B7‑33 delivered directly to your facility in the USA, UK, or Europe.B7-33 (6mg)

B7-33 (6mg)