How to Use B7-33
Complete guide to B7-33 dosing, administration, timing, and protocol recommendations.
Quick Overview
B7-33 is a 27-amino-acid, single-chain peptide cut down from the B-chain of human relaxin-2, the hormone that loosens tissue during pregnancy. Relaxin itself has strong anti-scarring effects but is a complex two-chain molecule that is hard and expensive to make, so an Australian group (Hossain and colleagues, 2016) designed B7-33 as a simpler version. In rodent models it reduced heart and lung fibrosis about as well as full relaxin. It has never been tested in humans.
Dosing Guidelines
Common Dose
No established human dose
Frequency
Once to twice daily in mouse studies
Dose Range
Not established (mouse studies used 0.25 mg/kg per dose)
Note: There is no published human dosing, pharmacokinetic, or safety data for B7-33. The very short serum half-life seen in lab testing means once-daily dosing may not keep levels up, which is why the mouse studies used twice-daily injections or continuous pumps. Any human dose discussed online is a guess.
Administration Method
Intraperitoneal or subcutaneous injection (including osmotic minipumps) in rodents
Best Time to Take
No evidence-based timing
Mouse studies used twice-daily injections or continuous infusion because the peptide clears quickly. No human timing data exist.
Protocol Duration
1-2 weeks in most rodent studies
Possible Side Effects
Not everyone experiences these. Individual responses vary.
- •No human safety data of any kind
- •Very short half-life in serum (about 6 minutes in vitro)
- •Relaxin-family signaling relaxes connective tissue; long-term effects on joints and ligaments unknown
- •Theoretical cancer concern from the relaxin family (B7-33 did not promote prostate tumors in mice, but this is not tested in humans)
- •Injection site reactions possible
Frequently Asked Questions
What is the recommended dose for B7-33?
No established human dose
How do you administer B7-33?
Intraperitoneal or subcutaneous injection (including osmotic minipumps) in rodents
When is the best time to take B7-33?
No evidence-based timing
How long should you use B7-33?
1-2 weeks in most rodent studies
This information is for educational purposes only. Always consult with a healthcare professional before using any peptide. Dosing information is based on research literature and community reports, not medical advice.