Urocortin-2_Dosage, benefits & legal status
Also known as urocortin II, Ucn2, UCN2, stresscopin-related peptide, urocortin-related peptide, NBI-69734
Real human hemodynamics from an investigator-led trial, and nobody took it forward.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Urocortin-2?
Plain language first. The technical label stays, but it never stands alone.Overview
This is a cousin of the body's main stress hormone signal, but it hits the other receptor in the family. That matters, because drugs blocking the first receptor failed repeatedly in anxiety and depression, and this one goes at the second receptor as an agonist instead. The interesting human work is about the heart. In 53 patients admitted with acute heart failure, a four-hour drip lowered blood pressure and raised the amount of blood the heart moved by more than half. Flushing was common, kidney blood markers rose during the infusion, and no company took the drug forward.
Urocortin-2 is a 41-residue peptide of the corticotropin-releasing factor family, selective for CRF receptor type 2 with no appreciable activity at CRF receptor type 1. UniProtKB Q96RP3 gives a 112-residue precursor with the mature chain at residues 72 to 112, and lists stresscopin-related peptide and urocortin-related peptide as alternative names. It was described in 2001 as a CRF family member selectively bound by type 2 CRF receptors. Its clinical interest is cardiovascular rather than psychiatric: infused in heart failure it lowers vascular resistance and raises cardiac output.
What it's used for
Nothing. It is a natural peptide with no approved product, studied in investigator-led infusion trials in heart failure and in healthy volunteers.
How does Urocortin-2 work?
What it does in the body, and where.The corticotropin-releasing factor family has two receptors, and almost all the drug attention went to the first one. Urocortin-2 is selective for the second, and what it does there is cardiovascular.
- 01Two receptors, two different storiesCRF receptor type 1 is the stress-axis receptor, and antagonists against it were tested repeatedly in anxiety and depression without success. Urocortin-2 is an agonist at type 2, described in its characterization paper as binding selectively to CRF-R2 with no appreciable activity on CRF-R1.
- 02What CRF2 activation does to the circulationIt widens blood vessels. In healthy volunteers, intra-arterial infusion produced sustained vasodilation that did not fade with repeated dosing and was partly dependent on nitric oxide. In heart failure patients, the same action lowers the resistance the heart pumps against.
- 03The heart failure resultIn 53 patients admitted with acute decompensated heart failure, a four-hour infusion lowered mean arterial pressure from 92 to 80 millimeters of mercury against 92 to 89 on placebo. In a 20-patient subset with right heart catheters, cardiac output rose by over 50 percent while placebo did not move.
- 04Why it stopped thereThe trial was investigator-led, not company-run, and the company that owned the compound said it would rely on outside parties for further clinical work. Creatinine rose during the infusion, flushing affected more than half the patients, and no larger outcome trial followed. Short-term hemodynamic improvement in heart failure has a long record of not translating into survival, as this site's nesiritide, ularitide and carperitide pages show.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
What the heart failure trial showed
peer-reviewed-human- Human trialFifty-three patients admitted with acute decompensated heart failure received a four-hour infusion of urocortin-2 or placebo on top of standard care, in an investigator-led trial run from the University of Otago at Christchurch Hospital.
- Human trialMean arterial pressure fell from 92 to 80 millimeters of mercury against 92 to 89 on placebo, P less than 0.001, across 27 and 26 patients respectively.
- Human trialIn a 20-patient catheterized subset, cardiac output rose by over 50 percent while placebo did not change, P of 0.003. That is a large hemodynamic effect for a four-hour infusion.
- Human trialPlasma creatinine rose over the infusion period, flushing affected 55 percent against 23 percent on placebo, and there was one heart failure death in the treated arm reported as unrelated to the drug.
Where this sits against the rest of the family
Research only- ReviewUrocortin-2 is a CRF2 agonist with no appreciable CRF1 activity. The repeated failures in anxiety and depression belong to CRF1 antagonists, a different receptor and the opposite direction of action, and this site's PT00114 page covers that history.
- lab-analysisThe naming is a trap. Stresscopin-related peptide is a genuine alternative name for urocortin-2, listed in the reference record. Stresscopin on its own refers to urocortin-3, a different peptide.
- lab-analysisLength is also misreported. The human mature chain is 41 residues by a positional read of the reference record and by vendor datasheets. A figure of 38 residues circulates in reviews and encyclopedia entries, and it does not correspond to the human chain annotated in the reference record.
What did not happen next
none- No dataNo larger outcome trial followed. The company holding the compound said it would continue to rely on outside parties to investigate it clinically, and no registry record for the heart failure trial was found.
- No dataShort-term hemodynamic gains in acute heart failure have repeatedly failed to become survival benefits. Nesiritide, ularitide and carperitide all have pages on this site telling versions of that story.
- Human trialThe registered urocortin studies that do exist are three small University of Edinburgh volunteer studies and one observational study that measured the peptide rather than giving it.
Because urocortin-2 belongs to the stress-hormone family, it gets written up as a stress or anxiety compound. Its human evidence is cardiovascular, and the direction of action is the opposite of the failed psychiatric drugs: those were CRF1 antagonists, and this is a CRF2 agonist. The trial figures also get inflated into more than they are. A four-hour infusion in 53 hospitalized patients that lowers blood pressure and raises cardiac output is a hemodynamic result, not evidence of benefit, and creatinine rose while it ran. Two identity traps are worth knowing. Stresscopin-related peptide is a real synonym for urocortin-2, but stresscopin alone is urocortin-3. The human peptide is 41 residues by a positional read of the reference record; a figure of 38 circulates in secondary sources and matches nothing annotated there. One further caution about a number we will not print: a widely repeated claim that 55 patients were randomized and 53 completed could not be confirmed, because the paper itself was unreachable. What is documented is 53 patients studied.
The published record
Papers and trials about Urocortin-2
Searched: urocortin 2, urocortin II, stresscopin-related peptide.
Left out: urocortin (alone) (pulls urocortin-1 and urocortin-3, which are different peptides with different receptor selectivity); stresscopin (on its own this refers to urocortin-3, not this peptide); corticotropin-releasing factor (the family, with a very large stress-biology literature); CRF2 (the receptor, shared across the family); UNICORN (the trial acronym is also used by an unrelated oncology study in non-small-cell lung cancer).
114 papers tagged human · 52 not reviews or lab · 5 clinical trial publications
6 registered trials · none with posted results
Furthest stage reached: Published trials only, 5 clinical trial publications, no phased trial registered
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Urocortin-2
How much, and do you cycle it?
The range, and whether you take breaks.No established dose, not applicable. Not established No range
Given only as a short infusion in research settings, with no repeat-dosing schedule established.
Not quoted hereNo figure
No figure was read from a primary source, so none is quoted. The studies used continuous infusion over one to four hours rather than single injections, the usual sign of rapid clearance. In healthy volunteers the vasodilator response was sustained through repeated dosing rather than fading.
You can compare this against the whole library to see where it sits.
How is it given?
Dosing context and source notes.Given in hospital from a prepared product, so there is nothing to mix.
No established dose. The heart failure work used a four-hour intravenous infusion given on top of standard care in the hospital, and an earlier chronic heart failure study used one-hour infusions at two fixed amounts. Those are monitored hospital infusion protocols, not doses that transfer anywhere else, and any figure offered as a urocortin-2 dose would be invented.
How do you store it?
Before mixing, and after.Given in a hospital or trial clinic, so the pharmacy stores it.
Urocortin-2 goes into a vein and is prepared by hospital, clinic or trial pharmacy staff, following the product label or the trial protocol. Some products like this are ready-made solutions and others are powders mixed just before use, often with hours rather than weeks of shelf life once prepared. It is not a medicine people store at home.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 24% charged residues, 56% hydrophobic. Acid may help.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- Any self-administered use: there is no product, no established dose, and the studied effects on blood pressure require hospital monitoring
- Any use outside a trial in acute heart failure: the only controlled data come from four-hour infusions given alongside standard care in the hospital
Stop and get help
- Not applicable outside a trial
Common effects
- Transient flushing, in just over half of those given it
- A fall in blood pressure and a rise in cardiac output, during the infusion
- A rise in plasma creatinine over the infusion period
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Urocortin-2 approved?
And where the numbers on this page come from.No. Urocortin-2 is not approved for any use, anywhere. It is sold labeled for laboratory research only, and there is no legal route to buy it for human use.
- Approval statusResearch only
- RouteInto a vein (4-hour infusion, in studies)
- Checked25 October 2026
- DoseNo dose has been established in people.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
What has happened recently
Not approved anywhere. Identity is settled: UniProtKB Q96RP3, a 112-residue precursor with the mature chain at residues 72 to 112, giving 41 residues. FDA substance record UNII 2IH21SQ983, and that record also carries the Neurocrine development code NBI-69734. Two different CAS numbers appear in different records for this peptide, so neither is given here as definitive. The main trial is reported as Chan and colleagues in JACC: Heart Failure 2013, volume 1, issue 5, pages 433 to 441, and its full title in journal indexes names it the UNICORN study, for Urocortin-2 in the Treatment of Acute Heart Failure as an Adjunct Over Conventional Therapy. The trial was run by the Cardioendocrine Research Group of the University of Otago at Christchurch Hospital in New Zealand, and Neurocrine Biosciences announced the results in May 2012 while saying it would continue to rely on outside parties to investigate the compound clinically. We could not open the paper itself through any route, so the figures here come from that announcement, and the one number we could not confirm is how many patients were randomized as against the 53 reported as studied. No registry record for the trial was found. Four registered urocortin studies exist, three of them University of Edinburgh volunteer studies and one an observational study measuring rather than giving the peptide.
You can compare this against the whole library, or read how to check a seller.
What else is like Urocortin-2?
Others in Sexual and hormonal, side by side.If you're weighing Urocortin-2, it's worth reading Elabela, PT-141 (Bremelanotide), and Kisspeptin in the same class.
Real human hemodynamics from an investigator-led trial, and nobody took it forward.
- Dose
- No established dose
- How often
- Not applicable
Discovered independently as Elabela and as Toddler, and the reference databases use a third name.
- Dose
- No established dose
- How often
- Not applicable
An approved shot that boosts sexual desire through the brain.
- Dose
- 1.75 mg per dose
- How often
- As needed, before activity
A peptide that switches on natural sex-hormone signaling for libido and fertility.
- Dose
- 0.1 up to 0.2 mg per dose
- How often
- Daily in vendor protocols
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- Chan and colleagues, JACC: Heart Failure(2013)Urocortin-2 Infusion in Acute Decompensated Heart Failure. Volume 1, issue 5, pages 433 to 441. Authors W. Y. Wandy Chan, Christopher M. Frampton, Ian G. Crozier, Richard W. Troughton and A. Mark Richards. Journal indexes carry the fuller title naming the UNICORN study and expanding it as Urocortin-2 in the Treatment of Acute Heart Failure as an Adjunct Over Conventional Therapy, although the Crossref title field stops at the short form. The full text could not be opened through any route we tried, so no figure on this page is taken from the paper itself.
- Neurocrine Biosciences, urocortin 2 phase 2 results in acute decompensated heart failure(2012)Dated May 17, 2012, and the source of every number on this page. A trial in 53 patients with acute decompensated heart failure, conducted by the Cardioendocrine Research Group of the University of Otago with patients at Christchurch Hospital, giving a four-hour infusion of urocortin 2 or placebo alongside standard care. Blood pressure data covered 27 patients on urocortin 2 and 26 on placebo: mean arterial pressure fell from 92 plus or minus 3 to 80 plus or minus 3 millimeters of mercury against 92 plus or minus 3 to 89 plus or minus 4 on placebo, P less than 0.001. In a 20-patient subset with right heart catheterization, 10 per arm, cardiac output increased by over 50 percent against no change on placebo, P of 0.003. Plasma creatinine rose during the four-hour infusion, with no significant differences in other clinical chemistry, hematology or urinalysis. Transient flushing affected 55 percent on urocortin 2 against 23 percent on placebo. There was one heart failure-related death in the urocortin 2 arm, 48 hours after infusion, stated as not related to drug, and no treatment-related serious adverse events. Neurocrine's chief executive said the company would continue to rely on outside parties to further investigate urocortin 2 clinically.
- Reyes and colleagues, Proceedings of the National Academy of Sciences(2001)The paper that named this peptide: Urocortin II, a member of the corticotropin-releasing factor neuropeptide family that is selectively bound by type 2 CRF receptors. Volume 98, issue 5, pages 2843 to 2848, February 27, 2001. The selective binding to CRF receptor type 2 with no appreciable activity at type 1 is the finding this page rests on. We have not resolved which species the peptide characterized here belongs to. That bears on the residue count discussed below, so no species claim is made from it.
- UniProtKB Q96RP3, urocortin-2 precursor(2026)Recommended name urocortin-2, with stresscopin-related peptide, urocortin II and urocortin-related peptide as alternative names and SRP and URP as gene synonyms. A 112-residue precursor with a signal at 1 to 22, a propeptide at 23 to 70 and the mature chain at 72 to 112. Read positionally, that chain is IVLSLDVPIGLLQILLEQARARAAREQATTNARILARVGHC, 41 residues.
Beyond these, 378 records are indexed. Browse the records