B7-33
Also known as: Relaxin, Relaxin-2, Single-chain Relaxin Peptide, RXFP1 Agonist
Relaxin-2 Analog | Anti-Fibrotic & Cardiovascular
Overview
B7-33 is a single-chain peptide analog of human relaxin-2 that selectively activates the relaxin family peptide receptor 1 (RXFP1). Unlike native relaxin-2, which requires a complex two-chain A/B structure connected by disulfide bonds, B7-33 achieves RXFP1 activation with a much simpler single-chain design. This makes it significantly easier and more cost-effective to synthesize. Preclinical research demonstrates potent anti-fibrotic, vasodilatory, and cardioprotective properties, positioning B7-33 as a promising therapeutic candidate for fibrotic diseases, heart failure, and vascular dysfunction.
Key benefits
- Potent anti-fibrotic activity across multiple organ systems
- Improved vasodilation and vascular compliance
- Cardioprotective effects and potential to attenuate cardiac remodeling
- Much simpler to synthesize than native two-chain relaxin-2
- Selective RXFP1 agonism with biased signaling profile
- Preclinical efficacy in models of heart failure and fibrosis
Mechanism of action
Selectively activates RXFP1, the primary receptor for relaxin-2, triggering downstream signaling cascades that inhibit fibroblast activation and collagen deposition, promote extracellular matrix remodeling via increased matrix metalloproteinase (MMP) activity, enhance nitric oxide-mediated vasodilation, and reduce inflammatory cytokine expression. B7-33 appears to preferentially engage pERK1/2 signaling pathways while showing reduced cAMP activation compared to native relaxin-2, suggesting biased agonism at RXFP1.
Molecular data
- Type
- Single-chain peptide
- Half-life
- Not well characterized
Sequence
Single-chain analog of relaxin-2 B-chain
Indications
What the research community uses this compound for, with self-reported effectiveness.
Cardiovascular
Anti-Fibrotic
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Delivery method
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| — | 100-250 mcg | 1x daily | — |
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Injection site reactions (redness, mild irritation)
- Potential transient hypotension due to vasodilatory effects
Contraindications
- Pre-existing hypotension or conditions exacerbated by vasodilation
- Pregnancy or breastfeeding (no safety data available)
- Concurrent use of potent antihypertensive agents without medical supervision
- No human safety data exists -- all protocols are extrapolated from preclinical research
References
Primary literature and clinical-trial data informing this entry.