HPLC · CoA
What Is ARA-290?
Explainer · 6 min read · Updated 30 September 2026
ARA-290, also named cibinetide, is an 11 residue synthetic peptide modelled on the helix B surface of erythropoietin that activates the innate repair receptor while leaving the red blood cell receptor untouched. The innate repair receptor joins one erythropoietin receptor to CD131, the beta common subunit. Its molecular weight is about 1257 g/mol, and laboratories use it to study tissue-protective and anti-inflammatory signalling in models of nerve, kidney and cardiac injury.
What Is ARA-290 Made Of?
ARA-290 is made of 11 residues, pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser, often written in single letters as QEQLERALNSS with the first residue cyclised to pyroglutamate. That cyclised residue caps the amino end, which is why papers often label the compound pHBSP, short for pyroglutamate helix B surface peptide. With three acidic residues against a single arginine and a blocked amino terminus, the peptide carries a net negative charge in neutral solution and dissolves easily in water.
Erythropoietin itself is a glycoprotein of 165 amino acids folded into four helices. Helix B faces away from the surface that binds the classic receptor pair, and that geometry is the basis of the design: a peptide taken from that face can reach the second receptor without engaging the first.
What Is the ARA-290 Mechanism of Action?
The ARA-290 mechanism of action is selective activation of the innate repair receptor, one of two receptor arrangements through which erythropoietin signals.
- The classic receptor is a pair of erythropoietin receptors. It responds to picomolar hormone levels and drives the maturation of red blood cells in bone marrow.
- The innate repair receptor pairs one erythropoietin receptor with CD131, the beta common subunit shared with receptors for GM-CSF, IL-3 and IL-5. It appears in tissue under stress, requires much higher local concentrations and switches on protective signalling.
In cell and animal models, activation of the second complex has been linked to reduced release of inflammatory cytokines such as TNF-alpha, preserved tissue after ischaemic or toxic injury, and signalling through JAK2 and downstream survival pathways. Because the classic receptor is spared, a study can examine those effects without changes in haematocrit or clotting confounding the result. Plasma half-life is reported in the order of two minutes, yet the signalling it triggers outlasts the molecule, which researchers attribute to downstream cascades rather than persistence of the peptide.
How Has ARA-290 Been Studied?
ARA-290 has been studied in cell and animal injury models and in two phase 2 clinical trials, building on receptor work first published in PNAS. In 2004 a PNAS paper reported that the hormone's protective action runs through a heteroreceptor pairing its own receptor with the beta common subunit. In 2008 a second PNAS paper showed that small peptides modelled on the tertiary structure of the hormone could protect tissue without stimulating red cell formation, which is the design principle behind this compound. The phase 2 trials followed: one in small fibre neuropathy linked to sarcoidosis, published in Molecular Medicine in 2013, and one in type 2 diabetes, published in the same journal in 2014. No phase 3 trial has been reported, and no regulator lists it as an approved medicine. Every paper we hold is listed in our ARA-290 research library.
How Does ARA-290 Compare With BPC-157 and KPV?
ARA-290, BPC-157 and KPV all appear in recovery research, but they come from unrelated parent proteins and act on different targets.
| Feature | ARA-290 | BPC-157 | KPV |
|---|---|---|---|
| Source | Helix B of erythropoietin | Partial sequence of a protein in gastric juice | C-terminal end of alpha-MSH |
| Length | 11 amino acids | 15 amino acids | 3 amino acids |
| Molecular weight | About 1257 g/mol | About 1419 g/mol | About 342 g/mol |
| Target studied | Innate repair receptor (EPOR plus CD131) | No single receptor; VEGFR2, nitric oxide and FAK pathways proposed | Intracellular NF-kappaB signalling; melanocortin receptor role debated |
| Clinical trial record | Phase 2, Molecular Medicine 2013 and 2014 | Very limited | None registered |
| Typical models | Nerve, kidney and heart injury | Tendon, gut and vascular injury in rodents | Intestinal and skin inflammation models |
The right choice depends on the pathway. ARA-290 in a 10mg research vial suits work on erythropoietin receptor biology and neuropathy models. BPC-157 research peptide has the widest rodent record for tendon and gut studies but no defined receptor. The tripeptide KPV in 10mg vials fits inflammatory signalling in epithelial models. Many recovery studies compare two of these side by side, and all three sit in our recovery research range.
How Is ARA-290 Reconstituted?
ARA-290 is reconstituted with bacteriostatic water, in which the acidic, net negative chain dissolves quickly and rarely needs acetic acid. We supply it as a single 10mg lyophilised vial. Divide 10 mg by the volume added to obtain the concentration; each U-100 unit equals 0.01 mL.
| Water added | mg/mL | mcg per unit | Units holding 1 mg |
|---|---|---|---|
| 1 mL | 10 | 100 | 10 |
| 2 mL | 5 | 50 | 20 |
| 4 mL | 2.5 | 25 | 40 |
| 5 mL | 2 | 20 | 50 |
Give the unopened vial time to lose its chill, wipe the rubber stopper with alcohol, run the bacteriostatic water diluent down the glass and swirl without shaking. Our reconstitution calculator covers other volumes.
How Should ARA-290 Be Stored?
Sealed ARA-290 vials are stored at -20 °C in their box and away from light, while mixed stock goes into a refrigerator held between 2 and 8 °C. Laboratories commonly apply the 28-day in-use window used for preserved multi-draw vials and do not return a mixed vial to the freezer. For a long study, the stock can be divided into single-use aliquots that are frozen once.
When Is ARA-290 the Right Research Tool?
ARA-290 is the right tool when a study needs erythropoietin-style tissue protection with the red cell effect removed, and we recommend it particularly for nerve and metabolic neuropathy models, where its phase 2 record gives useful context. Each ARA-290 lot passes HPLC at 98% or higher purity, mass spectrometry verifies its identity, and its certificate of analysis is matched by lot. For a short peptide from an entirely different family, see what Cartalax is.
Questions about what is ARA-290
Sources
- Erythropoietin mediates tissue protection through an erythropoietin and common beta-subunit heteroreceptor. Proceedings of the National Academy of Sciences. 2004.
- Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. Proceedings of the National Academy of Sciences. 2008.
Written by the Macropus Peptides technical team for in-vitro laboratory research reference. Not medical advice; products are not for human or veterinary use and are sold to buyers aged 18 and over.