Serelaxin
Serelaxin is a research peptide in the Relaxin Receptor Agonist class. Serelaxin binds the relaxin family peptide receptor 1, a G protein-coupled receptor expressed on vascular smooth muscle and endothelium. Signalling raises cyclic AMP and increases nitric oxide and endothelin type B receptor activity, producing systemic and renal vasodilation, and has additionally been reported to have antifibrotic effects mediated through reduced TGF-beta signalling.
For research use only.
Key Facts
- CAS
- 99489-94-8
- Molecular Weight (MW)
- 5963 g/mol
- Half-life
- —
- FDA status
- Withdrawn / Rejected
- Administration Route
- intravenous
- Frequency
- —
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
Research summary
Recombinant form of the human hormone relaxin-2, investigated for acute heart failure. A large phase 3 outcomes trial did not meet its primary endpoints and development was discontinued. Not FDA-approved.
Peptide Library's Serelaxin profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Protocol
- Dosage Range
- —
- Frequency
- —
- Cycle
- —
- Administration Route
- intravenous
- Reconstitution Guide
- —
Not yet checked against primary sources
These figures are compiled from earlier reference material. They have not been verified against FDA labelling, registered trials or published literature, no citation is attached to them, and none of them is a recommended dose. Serelaxin is queued for dosage evidence review.
Compare reported doses across the whole librarySequence & molecular data
| Molecular formula | C256H408N74O74S8 |
|---|---|
| Molecular weight | 5963 g/mol |
| CAS number | 99489-94-8 |
| PubChem CID | 71300755 |
| FDA UNII | W0122B976Y |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Serelaxin binds the relaxin family peptide receptor 1, a G protein-coupled receptor expressed on vascular smooth muscle and endothelium. Signalling raises cyclic AMP and increases nitric oxide and endothelin type B receptor activity, producing systemic and renal vasodilation, and has additionally been reported to have antifibrotic effects mediated through reduced TGF-beta signalling.
Studies
- Serelaxin, recombinant human relaxin-2, for heart failure patients: A systematic review and meta-analysis
- Effects of Serelaxin in Patients with Acute Heart Failure
- Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trial
- Human Recombinant Relaxin (Serelaxin) as Anti-fibrotic Agent: Pharmacology, Limitations and Actual Perspectives
- Serelaxin and acute heart failure
Regulatory & research status
Serelaxin was withdrawn from the market or rejected for approval. It is not an approved product.
| FDA status | Withdrawn / Rejected |
|---|---|
| Research status | Development discontinued |
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Clinical Trial |
Benefits
—
Potential Side Effects
No side effects listed yet for this entry.
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Serelaxin: frequently asked questions
What is Serelaxin?
Recombinant form of the human hormone relaxin-2, investigated for acute heart failure. A large phase 3 outcomes trial did not meet its primary endpoints and development was discontinued. Not FDA-approved.
How does Serelaxin work?
Serelaxin binds the relaxin family peptide receptor 1, a G protein-coupled receptor expressed on vascular smooth muscle and endothelium. Signalling raises cyclic AMP and increases nitric oxide and endothelin type B receptor activity, producing systemic and renal vasodilation, and has additionally been reported to have antifibrotic effects mediated through reduced TGF-beta signalling.
Is Serelaxin FDA approved?
No. Serelaxin is not currently FDA-approved. Its development or marketing was discontinued, which can happen for commercial reasons as well as safety or efficacy ones. Any material available today is not an approved product.
What peptides are similar to Serelaxin?
Compounds most often compared with Serelaxin include ARA 290 (Cibinetide), Atosiban and Carbetocin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Serelaxin, recombinant human relaxin-2, for heart failure patients: A systematic review and meta-analysis — Medicine (Baltimore), 2018External reference
- Effects of Serelaxin in Patients with Acute Heart Failure — N Engl J Med, 2019External reference
- Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trial — Lancet, 2013External reference
- Human Recombinant Relaxin (Serelaxin) as Anti-fibrotic Agent: Pharmacology, Limitations and Actual Perspectives — Curr Mol Med, 2022External reference
- Serelaxin and acute heart failure — Heart, 2016External reference
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Aug 30, 2026 · Version 1
This Serelaxin profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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