EmergingHealing & Recovery

B7-33

Relaxin

Relaxin-2 Analog | Anti-Fibrotic & Cardiovascular

Half-life

Not well characterized

Chain length

Not reported

Reference frequency

Once daily

Research overview

DoseGear research brief

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.

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.

Compound background

Development & research timeline

Study windows describe what researchers measured, not when an individual should expect a result.

Origin & development

Single-chain relaxin-2 analog developed by a Melbourne research collaboration.

What it is researched for

Preclinical fibrosis and cardiovascular research through functionally selective RXFP1 agonism.

Research observation window

No established human response window is reported.

Reference data

Lyophilized vial injectable protocols

Not personalized dosing instructions

Only injectable vial references are shown. Nasal, topical, and unsupported non-vial schedules are excluded.

Research context	Amount	Frequency	Route
Anti-fibrotic / Cardiovascular support	100-250 mcg	1x daily	SubQ

Reference cycle

4-8 weeks (preclinical extrapolation)

Reference storage

Lyophilized: freezer long-term; Reconstituted: 2-8 C for up to 28 days

Safety context

Reported side effects

Injection site reactions (redness, mild irritation)
Potential transient hypotension due to vasodilatory effects

Contraindications & cautions

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

Scientific references

01
A single-chain peptide derived from the relaxin B-chain selectively activates RXFP1
Scientific citationA single-chain peptide derived from the relaxin B-chain selectively activates RXFP1. Chemical Science (2016).
02
The single-chain relaxin mimetic, B7-33, maintains anti-fibrotic activity in liver and kidney fibrosis models
Scientific citationThe single-chain relaxin mimetic, B7-33, maintains anti-fibrotic activity in liver and kidney fibrosis models. British Journal of Pharmacology (2020).
03
The relaxin receptor as a therapeutic target -- perspectives from evolution and drug targeting
Scientific citationThe relaxin receptor as a therapeutic target -- perspectives from evolution and drug targeting. Pharmacology & Therapeutics (2018).
04
B7-33 replicates the vasoprotective effects of relaxin in mouse models of cardiovascular disease
Scientific citationB7-33 replicates the vasoprotective effects of relaxin in mouse models of cardiovascular disease. Annals of the New York Academy of Sciences (2017).

This DoseGear profile combines published scientific literature with lyophilized-vial protocol references. Citations are provided for independent review.

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