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. 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

Quick answer

What it is: Single-chain derivative of H2 relaxin’s B-chain, designed as an RXFP1-biased analog for anti-fibrotic research.

Typical research dose: Research; no established consumer dose

Reconstitution calculator ↓

Research summary, not medical advice.

Reviewed by Kymata Health Editorial Team

·Last updated: August 2026·Evidence: Strong preclinical

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Minutes-class analog (SKU unpublished)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

Use-case scores

0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.

Injury & tissue3.5/10
RXFP1 anti-fibrotic models are real. Gray-market B7-33 is not serelaxin and not a gym recovery peptide. Community / single-program ceiling after the catalog-misfile haircut.

Compound card

Sequence: Single-chain H2-relaxin B analog (B7-33)
Class: RXFP1-biased relaxin analog (not serelaxin, not BPC-157)
Formula: Single-chain H2-relaxin B analog
Status: Not FDA-approved · research use

Dose it

5 mg + 2 mL BAC water → 2.5 mg/mL · 200 mcg ≈ 8 units (U-100)

Open in calculator

How it works

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. 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.

Research Use Cases

✓Relaxin-analog identity: Low

Dosing

Phase	Dose	Frequency	Notes
Human consumer	None established	n/a	Vial math only.

Administration

Route / form

Research SC (vendor)

Timing

Not established.

Empty stomach?

No - Food timing is not critical.

Timeline

Preclinical

Anti-fibrotic models - not a gym recovery curve.

Who it is for

Relaxin-analog identity

Low

Real analog paper, illegitimate BPC-alternative marketing.

Reconstitution

Vial	Water	Concentration	Example dose
5 mg	2.0 mL BAC	2.5 mg/mL	No established dose. 200 mcg would be 0.08 mL = 8 units if someone still insists on drawing. That is not a protocol.

Change vial size or water volume? Open the reconstitution calculator.

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.

Limits of current evidence

The B7-33 paper is analog design, not a human recovery trial.
Serelaxin (recombinant H2 relaxin) had a separate heart-failure path. This SKU is not that program.
No established consumer dose. Calculator numbers are fill math.

Verdict

B7-33 is a relaxin B-chain analog with a 2016 chemistry paper. It is not BPC-157, not a heart-failure drug, and not a reason to skip cardiology. Vial math only. No consumer dose.

Interactions & Contraindications

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

B7-33 vs. BPC-157

Canonical comparison: B7-33 vs BPC-157

Attribute	B7-33	BPC-157
Identity	Relaxin B-chain analog (RXFP1)	Gastric pentadecapeptide
Literature	Anti-fibrotic analog papers	Animal repair / VEGF-NO papers
FDA	Research	Category 2 research

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

Frequently Asked Questions

Is B7-33 a BPC-157 analog?▼

No. It is a relaxin B-chain analog (RXFP1). Different receptor, different literature.

Is this serelaxin?▼

No. Serelaxin is recombinant two-chain H2 relaxin. B7-33 is a single-chain analog from a 2016 chemistry paper.

What dose?▼

None established for consumers. The reconstitution row is vial math, not a protocol.

Why is it under recovery?▼

Catalog filing. Physiology is relaxin/fibrosis/vascular. Not a tendon 15-mer.

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