peptideNot FDA-approvedResearch chemicalSerelaxin (recombinant relaxin-2) was studied in a phase III trial but was not granted FDA approval
Relaxin-2Benefits, Dosage & Interactions
Relaxin-2 is a peptide hormone, a naturally occurring biochemical compound composed of amino acid chains linked by peptide bonds. It is the most extensively studied member of the relaxin family of peptides. Research on Relaxin-2 focuses on tissue recovery. Relaxin-2 is administered by injection rather than orally.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Moderate — One published human randomized trial; results not yet replicated.
Evidence strengthModerate · 3/4
PreclinicalStrong human evidence
One published human randomized trial; results not yet replicated.
Plasma half-life
Short plasma half-life of a few minutes, requiring continuous infusion
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- 30 mcg/kg/day of serelaxin (recombinant human relaxin-2) in the RELAX-AHF trial[1]
- Route studied
- Intravenous infusion in the hospital setting[1]
- Frequency
- Continuous IV infusion for 48 hours[1]
- Cycle length
- 48-hour infusion during acute hospitalization for heart failure[1]
- Half-life
- Short plasma half-life of a few minutes, requiring continuous infusion[1]
- Storage
- Refrigerated, reconstituted immediately before infusion in the trial setting[1]
Reported for Relaxin-2 in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Relaxin-2 entry is written from. Each number matches an inline marker above.
- [1]Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trialTeerlink JR, Cotter G, Davison BA, Felker GM, Filippatos G, Greenberg BH, Ponikowski P, Unemori E, Voors AA, Adams KF Jr, Dorobantu MI, Grinfeld LR, Jondeau G, Marmor A, Masip J, Pang PS, Werdan K, Teichman SL, Trapani A, Bush CA, Saini R, Schumacher C, Severin TM, Metra M, RELAXin in Acute Heart Failure (RELAX-AHF) Investigators · The Lancet · 2013 · Peer-reviewed · PMID 23141816
- [2]Cardiovascular effects of relaxin-2: therapeutic potential and future perspectivesAlmeida-Pinto N, Dschietzig TB, Brás-Silva C, Adão R · Clinical Research in Cardiology · 2024 · Peer-reviewed · PMID 37721595
- [3]Relaxin-2 as a Potential Biomarker in Cardiovascular DiseasesAragón-Herrera A, Feijóo-Bandín S, Anido-Varela L, Moraña-Fernández S, Roselló-Lletí E, Portolés M, Tarazón E, Gualillo O, González-Juanatey JR, Lago F · Journal of Personalized Medicine · 2022 · Peer-reviewed · PMID 35887517
How to track Relaxin-2 doses
Relaxin-2 is tracked as a protocol rather than a single reminder: a vial with a concentration, a schedule that may be titrated or cycled, and a rotation of injection sites. Here is the record that keeps all three consistent.
- 1
Record the vial and concentration
Log the vial strength and the volume of bacteriostatic water you added so Relaxin-2 is stored as a concentration rather than a guess. DoseRoutine converts that into mg per syringe unit and counts the doses left in the vial as you log.
- 2
Set the schedule, not just a reminder
Enter the dose in mg and the frequency. Cycled protocols get a start and end date so the history stays accurate when Relaxin-2 comes out of the routine.
- 3
Rotate and log the injection site
Pick the site at the moment you log the dose. The site map shows what you used last and how recently, which is the part that drifts fastest when two compounds run on different frequencies.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
Review Relaxin-2 alongside your logged metrics and any relevant blood work every few weeks before changing the dose, so the change is a response to data rather than to a good or bad day.
What to log each time
- Dose in mg and the syringe units it worked out to
- Vial: reconstitution date, concentration, doses remaining
- Injection site and time
- Any side effects in the 24 h after the dose
What is Relaxin-2 studied for?
What is Relaxin-2?
Relaxin-2 is a peptide hormone, a naturally occurring biochemical compound composed of amino acid chains linked by peptide bonds. It is the most extensively studied member of the relaxin family of peptides. In humans, Relaxin-2 is primarily produced by reproductive organs, especially during pregnancy in the corpus luteum, placenta, and decidua. However, it is also expressed in other tissues, including the heart, brain, and kidneys, suggesting broader physiological roles beyond reproduction (PubChem, NIH ODS). Its primary function is associated with collagen remodeling, angiogenesis (formation of new blood vessels), and anti-inflammatory processes.
Historically, relaxins were first identified for their role in facilitating parturition (childbirth) by relaxing the pubic symphysis and softening the cervix. Subsequent research has unveiled a more extensive range of actions for Relaxin-2, particularly its involvement in connective tissue metabolism, systemic hemodynamics, and protection against fibrosis in various organs. Due to its multifaceted biological activities, Relaxin-2 has garnered interest for its potential therapeutic applications in conditions characterized by fibrosis, inflammation, and tissue remodeling (DrugBank). Its half-life in the human body is approximately 8 hours, meaning it takes about 8 hours for half of the administered substance to be eliminated from the bloodstream.
What does the research say about Relaxin-2?
Tap a section to expand.
Relaxin-2 exerts its biological effects primarily through binding to and activating specific G protein-coupled receptors (GPCRs), predominantly the Relaxin Family Peptide Receptor 1 (RXFP1) and to a lesser extent RXFP2 (PubChem). The activation of RXFP1 initiates a cascade of intracellular signaling pathways that lead to its diverse physiological actions.
Key mechanistic actions of Relaxin-2 include:
* **Collagen Remodeling:** Relaxin-2 plays a significant role in modulating extracellular matrix (ECM) turnover. It can inhibit the production of collagen and stimulate the activity of matrix metalloproteinases (MMPs), enzymes responsible for breaking down collagen and other ECM components. This action is crucial in preventing and reversing fibrosis, a process characterized by excessive accumulation of collagen and scar tissue.
* **Anti-inflammatory Effects:** Relaxin-2 has demonstrated anti-inflammatory properties by inhibiting the expression of pro-inflammatory cytokines and chemokines. It can also modulate the activity of immune cells, reducing the inflammatory response in various tissues.
* **Vasodilation and Angiogenesis:** Relaxin-2 promotes vasodilation (widening of blood vessels) by increasing nitric oxide production, leading to improved blood flow. It also stimulates angiogenesis, the formation of new blood vessels, which is important for tissue repair and oxygen supply.
* **Antifibrotic Signaling:** Through its interaction with RXFP1, Relaxin-2 activates signaling pathways such as the Akt/eNOS pathway, leading to increased nitric oxide production, and the PKA/cAMP pathway, which mediates many of its cell-relaxing and antifibrotic effects. These pathways collectively contribute to its ability to attenuate fibrosis in organs like the heart, lungs, and kidneys (DrugBank, NIH ODS).
Research into Relaxin-2's potential benefits stems largely from its established roles in tissue remodeling, anti-fibrosis, and anti-inflammation. While its primary physiological functions are well-understood, therapeutic applications are still largely under investigation or in clinical development.
Potential areas of benefit being explored include:
* **Cardiac Fibrosis and Heart Failure:** Studies have investigated Relaxin-2 for its ability to reduce cardiac fibrosis and improve cardiac function in models of heart failure. Its vasodilatory and antifibrotic properties are thought to contribute to these effects, potentially mitigating the structural and functional changes associated with heart failure (Cochrane, MedlinePlus).
* **Renal Fibrosis:** Given its antifibrotic mechanisms, Relaxin-2 is being studied for its potential to ameliorate kidney fibrosis, a common pathway to chronic kidney disease progression. Experimental evidence suggests it can reduce collagen deposition and inflammation in the kidneys.
* **Pulmonary Fibrosis:** Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease characterized by excessive scar tissue formation. Relaxin-2's ability to inhibit collagen synthesis and promote its degradation makes it a candidate for potentially slowing the progression of such fibrotic lung conditions.
* **Systemic Sclerosis (Scleroderma):** This autoimmune disease involves widespread fibrosis of the skin and internal organs. The antifibrotic actions of Relaxin-2 have led to investigations into its potential to reduce collagen accumulation and improve symptoms in affected individuals (NIH ODS).
* **Wound Healing and Scarring:** By modulating collagen turnover, Relaxin-2 might influence the quality of wound healing, potentially reducing excessive scar formation. Its angiogenic effects could also contribute to more efficient tissue repair.
Further clinical trials are ongoing to fully establish the safety and efficacy of Relaxin-2 for these and other conditions. It is important to note that many of these potential applications are still experimental.
The evidence supporting the roles and potential therapeutic applications of Relaxin-2 is derived from various sources, including basic science research, animal models, and preliminary human clinical trials.
* **Basic Science and In Vitro Studies:** Extensive in vitro research has elucidated the molecular mechanisms by which Relaxin-2 interacts with its receptors (RXFP1/RXFP2) and triggers downstream signaling pathways (e.g., Akt, eNOS, PKA). These studies have provided foundational evidence for its roles in collagen synthesis inhibition, MMP activation, vasodilation, and anti-inflammatory responses (PubChem).
* **Animal Models:** Numerous animal studies (e.g., in rats, mice, pigs) have demonstrated the antifibrotic, anti-inflammatory, and vasodilatory effects of Relaxin-2 across various organ systems. For example, animal models of cardiac fibrosis, renal fibrosis, pulmonary fibrosis, and liver fibrosis have shown that Relaxin-2 administration can reduce collagen deposition, improve organ function, and decrease inflammation (NIH ODS, Examine.com).
* **Human Clinical Trials:** Early-phase human clinical trials have investigated the safety and pharmacokinetics of synthetic Relaxin-2 (e.g., serelaxin) in conditions like acute heart failure. Some trials have explored its effects on renal function and congestion in heart failure patients. While some trials have shown promise in improving certain parameters like renal function and reducing short-term mortality in specific heart failure populations, others have yielded mixed results regarding broader clinical outcomes. Large-scale, definitive clinical trials are often required to establish widespread efficacy and gain regulatory approval for specific indications (DrugBank, MedlinePlus).
* **Review Articles and Meta-Analyses:** Comprehensive review articles and meta-analyses, particularly from organizations such as Cochrane, frequently synthesize the available evidence from multiple studies. These analyses help in assessing the overall strength and consistency of the evidence for Relaxin-2's potential therapeutic uses.
Overall, the evidence suggests a strong mechanistic basis and promising preclinical data for Relaxin-2's therapeutic potential, particularly in fibrotic and inflammatory conditions. However, the translation of these findings into widespread clinical practice is ongoing and requires further robust clinical investigation.
Based on clinical trials and pharmacological studies, Relaxin-2, particularly in its recombinant forms, has been associated with certain side effects. The reported side effects are generally mild to moderate.
Commonly reported side effects include:
* Headache
* Nausea
* Vomiting
* Dizziness
* Hypotension (low blood pressure), especially with rapid or high-dose administration, due to its vasodilatory effects.
* Local injection site reactions (if administered via injection) such as pain, redness, or swelling.
Less common side effects might include:
* Tachycardia (increased heart rate)
* Fatigue
* Back pain
It is important to promptly report any adverse reactions to a healthcare professional. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Relaxin-2, due to its physiological actions, necessitates certain warnings and precautions.
* **Hypotension Risk:** As Relaxin-2 can induce vasodilation, there is a risk of dose-dependent hypotension (low blood pressure). Patients with pre-existing low blood pressure or those taking other medications that lower blood pressure should be monitored carefully.
* **Renal Impairment:** While some studies suggest benefits in renal function, caution is advised in patients with severe renal impairment, and dose adjustments may be necessary.
* **Hepatic Impairment:** Data on the use of Relaxin-2 in patients with severe hepatic impairment are limited. Close monitoring is recommended.
* **Pregnancy and Lactation:** Although naturally occurring Relaxin-2 is crucial during pregnancy, the safety of exogenous (administered) Relaxin-2 during pregnancy and lactation has not been established. Its use should be carefully considered and discussed with a clinician.
* **Use in Children and Adolescents:** The safety and efficacy of Relaxin-2 in pediatric populations have not been established.
Always discuss your full medical history and all current medications, including over-the-counter drugs and supplements, with your healthcare provider before considering Relaxin-2. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Specific contraindications for Relaxin-2 are still being defined as its therapeutic use is not yet widespread for all potential indications. However, based on its known mechanisms of action and potential side effects, certain conditions may pose risks.
* **Known Hypersensitivity:** Individuals with a known allergy or hypersensitivity to Relaxin-2 or any of its excipients should avoid its use.
* **Severe Hypotension:** Due to its vasodilatory effects, Relaxin-2 may be contraindicated in patients experiencing severe, unmanaged hypotension or cardiogenic shock where further blood pressure reduction could be detrimental.
* **Severe Aortic Stenosis:** In conditions where increased vasodilation could compromise cardiac output, such as severe aortic stenosis, caution is generally warranted.
Decisions regarding the use of Relaxin-2 in specific conditions should always be made by a qualified healthcare professional, weighing the potential benefits against the risks. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
While specific interactions with Relaxin-2 are still under thorough investigation for its various potential therapeutic applications, theoretical or observed interactions based on its known mechanisms exist.
* **Antihypertensive Medications:** Given Relaxin-2's vasodilatory properties and potential to lower blood pressure, concomitant use with other antihypertensive agents (e.g., ACE inhibitors, ARBs, calcium channel blockers, diuretics) could lead to an additive hypotensive effect, potentially causing dangerously low blood pressure. Close blood pressure monitoring is essential if these are co-administered.
* **Nitrates:** Medications like nitrates, which also induce vasodilation, could potentiate the hypotensive effects of Relaxin-2.
* **Diuretics:** Co-administration with diuretics might increase the risk of dehydration and electrolyte imbalances, particularly in patients with heart failure.
Due to the ongoing research and developing understanding of Relaxin-2's therapeutic applications, it is crucial to inform your clinician about all medications, supplements, and other substances you are taking to avoid potential adverse interactions. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Relaxin-2 is a peptide, and its administration is typically via injection due to its polypeptide structure, which would be degraded in the digestive system if taken orally. The specific timing and frequency of administration would be determined by the therapeutic goal, the compound formulation, and individual patient needs, as prescribed by a licensed clinician.
In studies, the half-life of Relaxin-2 is recorded to be around 8 hours. This pharmacokinetic characteristic often influences dosing frequency in clinical settings, with typical regimens being once or twice daily injections to maintain therapeutic levels. However, this parameter can vary based on individual metabolism and specific disease states.
For most peptides, absorption and efficacy are not typically influenced by food intake. Therefore, Relaxin-2 can generally be administered with or without food. The precise timing relative to meals will be specified by the prescribing clinician based on the treatment plan.
What interacts with Relaxin-2?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any peptide + hormone | Note | Category ruleConfidence: theoretical | Injectable peptides plus hormones can have overlapping or compounding effects that aren't always well characterized.Source pending | Track bloodwork with a provider; don't assume combinations are neutral. |
Frequently asked questions about Relaxin-2
Relaxin-2 is a research peptide. What follows is drawn from peer-reviewed literature indexed on PubMed, FDA label text where a label exists, and NIH reference records.
Relaxin-2 is commonly discussed in the context of supporting recovery. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Relaxin-2, it is typically administered by injection and it is typically taken null. Always follow the specific dose your clinician or the product label prescribes.
Relaxin-2 carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
Relaxin-2 is a peptide, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Relaxin-2 with no sign-up.
Combining a peptide like Relaxin-2 with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Each peptide class carries its own profile against Relaxin-2: a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Relaxin-2 varies by protocol and formulation, so the label or prescription is what sets it. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Relaxin-2 depends on the protocol and formulation you are on. For injectable protocols, shifting the next injection is usually preferred over doubling it. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For an injectable like Relaxin-2 the record needs more than a checkbox: vial concentration, the measured volume, and which site the last injection went into. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Relaxin-2?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.The dual and multifaceted role of relaxin-2 in cancer(opens PubMed in a new tab)Clin Transl Oncol · 2023 · PMID 36947362 · https://pubmed.ncbi.nlm.nih.gov/36947362/
- 2.Cardiovascular effects of relaxin-2: therapeutic potential and future perspectives(opens PubMed in a new tab)Clin Res Cardiol · 2024 · PMID 37721595 · https://pubmed.ncbi.nlm.nih.gov/37721595/
Verify at
Publisher search links for Relaxin-2. These are places to check the information — they are not citations, so they are not numbered.
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- PubChem(publisher search, opens in a new tab)National Center for Biotechnology Information · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- Examine.com(publisher search, opens in a new tab)Examine.com · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed labeling archive(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Relaxin-2?
Plain-text summary, safe to quote verbatim:
Relaxin-2 is a peptide hormone, a naturally occurring biochemical compound composed of amino acid chains linked by peptide bonds. It is the most extensively studied member of the relaxin family of peptides. Research on Relaxin-2 focuses on tissue recovery. Relaxin-2 is administered by injection rather than orally.
Source: DoseRoutine — https://doseroutine.com/library/relaxin-2
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Relaxin-2 — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/relaxin-2
What compounds are similar to Relaxin-2?
Others in the peptide category or studied for the same goals.
Which goals is Relaxin-2 used for?
Other compounds studied for the same benefits as Relaxin-2.
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