Healing & Recovery

B7-33

Relaxin-2 B-chain analog · single-chain relaxin analog

Single-chain derivative of H2 relaxin’s B-chain, designed as an RXFP1-biased analog for anti-fibrotic research (PMID 27390301). Sold on FitScience / Dosage Peptide menus. Not serelaxin, not a heart-failure drug, not a recovery peptide just because vendors file it next to BPC.

Not FDA-approved — research chemical
Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Strong preclinical1 peer-reviewed citation
Typical research dose
Research; no established consumer dose
Frequency
Not established
Half-life
Minutes-class analog (SKU unpublished)
Common vials
5 mg
CAS
N/A
Dose it
5 mg + 2 mL BAC water → 2.5 mg/mL · 200 mcg ≈ 8 units (U-100)
Open in calculator

Mechanism of Action

B7-33 is a single-chain analog of the H2-relaxin B-chain, designed to keep RXFP1 signaling without the two-chain complexity of native relaxin (PMID 27390301). Preclinical anti-fibrotic and vascular papers exist.

It is not serelaxin, not BPC-157, and not a healing-stack ingredient just because a catalog parks it there.

Source: PMID: 27390301

Dosing Protocol

Typical DoseResearch; no established consumer dose
FrequencyNot established
Half-LifeMinutes-class (relaxin-family analog; SKU PK unpublished)
Common Vial Sizes5 mg

Dosing Protocols

Human consumer

Dose
None established
Frequency
n/a
Note: Vial math only.

Administration

Route
Research SC (vendor)
Timing
Not established.
Fasting Required?
No — food timing not critical

Expected Timeline

Preclinical
Anti-fibrotic models — not a gym recovery curve.

Who Is It For?

Relaxin-analog identity

Low

Real analog paper, illegitimate BPC-alternative marketing.

Reconstitution Example

Vial
5 mg
Diluent
2 mL
Concentration
2.5 mg/mL
Per Unit (100u syringe)
25 mcg
Dose of 200 mcg = 8 units on a 100-unit insulin syringe
🧮 Calculate Your Exact B7-33 Dose →

Safety & Considerations

Relaxin-family signaling hits vasculature and fibrosis biology. No consumer safety file. Not a substitute for cardiology or hepatology care.

Regulatory & Legal Status

FDA Status (US)
Research Only

Relaxin B-chain analog. Not serelaxin. No FDA approval

WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

B7-33 vs. BPC-157

AttributeB7-33BPC-157
IdentityRelaxin B-chain analog (RXFP1)Gastric pentadecapeptide
LiteratureAnti-fibrotic analog papersAnimal repair / VEGF-NO papers
FDAResearchCategory 2 research

Verdict: B7-33 is not a BPC cousin. Relaxin receptor ≠ gastric pentadecapeptide.

Dosing Quick Reference

B7-33— Dosing Guide
Dose Range
Research; no established consumer dose
Half-Life
Minutes-class (relaxin-family analog; SKU PK unpublished)
Frequency
Not established
Route
Subcutaneous
5 mg vial
💧 2 mL BAC water📐 2.5 mg/mL💉 25 mcg/unit (100u syringe)
Healing & Recoverycalcmypeptide.com

Frequently Asked Questions

Is B7-33 a BPC-157 analog?▼
No. It is a relaxin B-chain analog (RXFP1). Different receptor, different literature.

References

  1. Hossain MA / Bathgate RA et al. “A single-chain derivative of human relaxin-2 (B7-33).” Chemical Science / related relaxin analog work (2016). PMID: 27390301

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