Recovery ⏱ Half-life: Not fully characterized. Preclinical

B7-33

B7-33 (Relaxin Analog)

Updated March 15, 2026

Evidence at a Glance

Regulatory statusPreclinical
Single-chain relaxin-2 B-chain derivative; no human trials conducted.
Human evidenceNone
Animal evidenceLimited

B7-33 is a single-chain relaxin-2 derivative with promising anti-fibrotic results in cell and rodent studies, but it has never been tested in humans.

What the research does not support

  • Has no human clinical trials and no established human dose or safety data.
  • Is not FDA-approved and is not a proven treatment for any fibrotic, cardiac, or renal condition.
  • All evidence comes from cells and rodents; its effects in people are unknown.
Half-Life
Not fully characterized.
Mol. Weight
~3600 g/mol

What is B7-33?

B7-33 represents a breakthrough in relaxin-based research — a simplified, single-chain peptide that captures the anti-fibrotic properties of the complex relaxin hormone. Fibrosis (scarring) is a component of many chronic diseases, making this a broadly relevant research compound.

Research Applications

Anti-fibrotic research, cardiac fibrosis, pulmonary fibrosis, renal fibrosis, and RXFP1 receptor signaling.

Dosage Information (Research Use)

Animal research: varies by model. Subcutaneous administration. Research use only.

Reconstitution & Handling

Standard BAC water reconstitution.

Half-Life & Pharmacokinetics

Not fully characterized.

Reported Observations in Literature

Reduced cardiovascular effects compared to native relaxin. Generally well-tolerated in animal models.

Key Research References

  • Hossain MA, et al. “A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor RXFP1.” Chem Sci. 2016

How B7-33 Works

B7-33 is a simplified single-chain analog of relaxin-2 that activates RXFP1 (relaxin family peptide receptor 1) to promote anti-fibrotic signaling. Unlike native relaxin (a complex two-chain peptide), B7-33 is easier to manufacture and selectively activates anti-fibrotic pathways while minimizing cardiovascular effects.

Research Findings

Shown to reduce established fibrosis in cardiac and lung models. Addresses the manufacturing challenge of native relaxin while retaining therapeutic potential.

Dosage & Administration

Animal research: varies by model. Subcutaneous administration. Research use only.

Safety & Side Effects

Reduced cardiovascular effects compared to native relaxin. Generally well-tolerated in animal models.

Important: All safety information is derived from published research, primarily animal studies. No controlled human clinical trial data exists unless explicitly noted. This compound is sold for research purposes only.

Quick Facts

Sequence Single-chain B-chain analog of relaxin-2
Molecular Weight ~3600 g/mol
Half-Life Not fully characterized.
Available Sizes 1mg
Storage Lyophilized: -20°C. Reconstituted: 2-8°C.

Key Research References

  • Hossain MA, et al. "A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor RXFP1." Chem Sci. 2016

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