ARA-290: Innate Repair Receptor Agonist Mechanism, Neuropathy Research & Clinical Potential

What Is ARA-290?

ARA-290 (international nonproprietary name: cibinetide) is a synthetic 11-amino-acid peptide derived from the helix-B surface domain of erythropoietin (EPO), designed to activate the Innate Repair Receptor (IRR) — a heterocomplex of the EPO receptor and the β-common receptor (CD131). It does not stimulate red blood cell production, avoiding the hematopoietic effects of full EPO.

Molecular Identity and Structure

1. Amino acid sequence: pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser (one-letter: UEQLERALNSS)

2. CAS Number: 1208243-50-8

3. Molecular weight: 1,257.32 g/mol (formula C51H84N16O21)

4. Also known as: cibinetide, pyroglutamate helix B surface peptide (pHBSP, PH-BSP)

5. Non-erythropoietic, tissue-protective analog

The N-terminal pyroglutamate residue — a cyclized glutamine — is the structural feature that gives the peptide its rigidity and its selectivity for the innate repair receptor over the erythropoietic receptor homodimer. Any certificate of analysis that reports a different sequence or mass is not describing this compound.

Discovery and Research Origin

Developed by Dr. Michael Brines and Dr. Anthony Cerami, whose team delimited EPO's tissue-protective domains down to short peptide sequences in Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin (PNAS, 2008). That work built on their earlier finding that EPO's tissue protection is mediated by a distinct EPO-receptor/CD131 heteroreceptor rather than the receptor homodimer driving erythropoiesis. Clinical development was carried out by Araim Pharmaceuticals.

Legal Classification and Regulatory Status

Not approved for human use by FDA, EMA, or TGA Australia. Regulated as an investigational agent. For athletes, ARA-290 falls under the WADA Prohibited List category S0 (Non-Approved Substances) — which covers any pharmacological substance with no current approval by a governmental regulatory authority for human therapeutic use, and which is prohibited at all times, in and out of competition (as of August 2026).

ARA-290 belongs to a broader class of tissue-protective peptides that activate regenerative signaling without hormonal stimulation. For the full landscape of healing compounds including BPC-157 and TB-500, see our tissue repair and injury healing peptides guide and review ARA-290 purity data from independent lab tests.

How Does ARA-290 Work Biologically?

The primary mechanism involves selective activation of the Innate Repair Receptor (IRR), triggering anti-inflammatory, neuroprotective, and metabolic signaling without stimulating erythropoiesis.

Innate Repair Receptor Activation Pathway

ARA-290 binds the EPO-receptor/CD131 heterocomplex → activates JAK2/STAT3 and PI3K/Akt signaling → produces anti-inflammatory and anti-apoptotic effects. Critically, the IRR is locally upregulated at sites of tissue injury, which is why the peptide's action is concentrated where damage has occurred rather than distributed systemically.

Downstream Tissue-Specific Effects

6. Nervous system: Promotes small nerve fiber regeneration and reduces neuropathic pain signaling (the best-evidenced effect in humans)

7. Metabolic tissues: Improves glycemic and lipid markers in type 2 diabetes

8. Cardiovascular and kidney: Tissue protection observed in preclinical ischemia and fibrosis models

Evidence levels differ sharply across these tissues: the nervous-system and metabolic effects have Phase 2 human data behind them, while the cardiovascular and renal effects remain animal-model findings only.

Selectivity Over Full EPO

Unlike recombinant EPO, ARA-290 does not activate the homodimeric EPO receptor → no increase in hematocrit or thrombotic risk. Hemoglobin was unchanged in the human trials.

For comparison with full erythropoietin and its performance-enhancing effects, see our EPO (erythropoietin) red blood cell stimulation research and the EPO peptide guide. The anti-inflammatory signaling activated by ARA-290 parallels immune-modulating peptides covered in our immune support and longevity peptides guide.

Benefits of ARA-290 (Based on Preclinical & Phase II Trials)

Effects observed in animal models and Phase 2 human trials, concentrated on small fiber neuropathy and metabolic control. All human trials were small, and the program never advanced past Phase 2.

Neuropathic Symptom Reduction in Sarcoidosis

In the randomized, double-blind pilot trial (Molecular Medicine, 2012, n=22), patients with sarcoidosis-associated small fiber neuropathy received 2 mg intravenously three times weekly for 4 weeks. The ARA 290 group improved significantly on the Small Fiber Neuropathy Screening List versus placebo (Δ −11.5 vs Δ −2.9, p < 0.05), with improvements in the pain and physical-functioning dimensions of the SF-36. Hemoglobin was unchanged.

Nerve Fiber Regeneration — the Objective Endpoint

The larger dose-ranging Phase 2b trial (n=64, 1–8 mg subcutaneously daily for 28 days) reported a significant increase in corneal nerve fiber area and in GAP-43-positive regenerating intraepidermal nerve fibers at the 4 mg dose — objective structural evidence of nerve regrowth rather than symptom report alone. Notably, pain did not separate significantly from placebo in that trial, and 4 mg outperformed both 1 mg and 8 mg, so more was not better.

Metabolic Effects in Type 2 Diabetes

In a Phase 2 trial of 4 mg self-administered subcutaneously daily for 28 days in type 2 diabetes (Brines et al., Molecular Medicine, 2015), the treated group showed improvement in HbA1c (p = 0.002), lipid profile, and PainDetect neuropathic symptom score, with benefits persisting through a 56-day observation window. The HbA1c change was small in absolute terms (on the order of 0.2 percentage points) and this remains a single exploratory trial.

What Has Not Been Shown

9. No Phase 3 trial has been conducted for any indication

10. No head-to-head trial against gabapentin, duloxetine, or any standard neuropathy drug exists

11. Clinical development stalled after 2020 with no approval in any jurisdiction

ARA-290's tissue repair effects are frequently compared to BPC-157 and TB-500, which activate regeneration through different pathways. For detailed mechanism comparisons, see our BPC-157 science, healing mechanism and safety and TB-500 thymosin beta-4 tissue repair science. Compare lab-tested purity for BPC-157 and TB-500 across shops.

Side Effects and Safety Profile

No safety concerns were raised by clinical or laboratory assessment across the Phase 2 trials, and no serious adverse events were attributed to the compound. That record covers fewer than 150 trial participants over courses of 4 to 12 weeks — a favorable signal, not a demonstration of long-term safety.

Known Adverse Reactions

12. Mild injection-site irritation

13. Transient flushing after intravenous administration

14. No hematological changes (RBC, Hgb, Hct stable across trials)

Long-Term Unknowns

15. No safety data beyond 12 weeks of continuous use

16. Oral bioavailability not established

17. Teratogenicity unknown — avoid during pregnancy

18. Effects of chronic IRR activation on tumor surveillance and immune function are uncharacterized

Evidence Status Table

Dosage and Administration Protocols

Doses below are the protocols used in published clinical trials. They are reported here as documentation of what was studied, not as a recommended regimen — ARA-290 has no approved dosing for human use.

Trial-Anchored Dose Range

19. Intravenous: 2 mg three times weekly for 4 weeks (sarcoidosis pilot trial)

20. Subcutaneous: 4 mg daily for 28 days (type 2 diabetes trial and the dose-ranging trial's optimal arm)

21. The dose-ranging trial tested 1, 4 and 8 mg — 4 mg outperformed both the lower and the higher dose

Cycle Length and Timing

Published courses ran 28 days, with one macular-edema study extending to 12 weeks. The peptide is cleared from circulation within minutes, but downstream signaling effects are thought to persist far longer — which is the stated rationale for daily rather than continuous dosing. No trial has tested repeated or long-term cycles, so cycle-repetition practices circulating in the community have no trial basis.

Delivery Methods

22. Intravenous (used in the earliest trial)

23. Subcutaneous (used in the later and larger trials; the route with the most human data)

24. Topical and intranasal — not established in human trials

Stacking Strategies (Community Insights)

No clinical trial has evaluated ARA-290 in combination with any other peptide. Everything in this section is community practice, and combination use carries the compounded uncertainty of both compounds plus their unstudied interaction.

Reported Combinations

25. With BPC-157 — reported for tissue healing; no combination data exists, and effect claims circulating in forums are not measured outcomes

26. With TB-500 — reported for vascularization and nerve regeneration; likewise unstudied in combination

27. With Low-Dose Naltrexone (LDN) — reported for anti-inflammatory effect; no interaction data

Because the innate repair receptor is upregulated at injury sites rather than following a documented circadian rhythm, timing claims tied to receptor cycling are not supported by published receptor-expression data. If you are running a combination protocol, log it — a documented protocol tied to a lab-tested vial is worth more than an anonymous forum report.

Where to Buy ARA-290 Safely (Harm Reduction Guide)

Due to lack of regulatory approval, sourcing carries risks. Third-party verification is essential — and for this compound, identity verification matters more than purity.

Third-Party Testing Essentials

28. Demand HPLC + mass spectrometry certificates from shops

29. Confirm the mass: 1,257.32 g/mol. An 11-residue peptide with a pyroglutamate N-terminus is easy to mis-synthesize and easy to mislabel — mass spectrometry is the only check that confirms you have cibinetide and not a different short peptide. Our guide to mass spectrometry for verifying peptide identity explains how to read the report

30. Check purity against the 95% research-grade / 98% strong-result bar described in our peptide purity standards guide

Across independently submitted third-party tests, ARA-290 carries a Purity Index score of 98.69 across 76 tests from 12 labs — below the platform-wide composite of 99.49, and one of the lower-scoring indexed compounds (verified August 2026). That gap is the argument for batch-level verification on this specific peptide.

Independent verification is the only way to confirm compound identity and purity. Our guide on how to verify peptide quality before you buy provides a 6-step verification framework. Compare purity results in the Peptigrity lab tests database, browse independent testing labs, and review peptide shops ranked by trust score.

Red Flags

31. No Certificate of Analysis provided, or a COA that does not match the batch

32. A COA reporting a mass or sequence other than the ones above

33. Claims of "FDA-approved," "human-grade," or "clinically proven" — all false for this compound

See our peptide testing guide for step-by-step instructions on sending samples to independent labs.

Real-World User Experiences (Reddit, Podcasts, YouTube)

Community reports on ARA-290 are sparse compared with mainstream research peptides, and none of them constitute evidence — they are uncontrolled, unverified, and subject to reporting bias in both directions. Neuropathy also fluctuates naturally, which makes individual before-and-after accounts particularly unreliable for a compound targeting nerve pain.

What community discussion is useful for is the sourcing layer: which vendors supply the compound, whether COAs are batch-matched, and how independently tested material compares. That is the conversation happening in our community discussions, where every thread sits beside the lab data.

Alternatives to ARA-290

Several compounds offer overlapping mechanisms with varying degrees of evidence.

Pharmaceutical Options

34. Gabapentin and pregabalin: approved for neuropathic pain, with sedation and dizziness as common limitations

35. Duloxetine: FDA-approved for diabetic peripheral neuropathic pain, moderate efficacy, side effects common

These are the evidence-backed options for neuropathic pain, with regulatory approval and large trial programs behind them. ARA-290 has neither.

Endogenous Repair Peptides

36. BPC-157: broader tissue repair claims, but no published human efficacy trials. See BPC-157 science, healing mechanism and safety.

37. TB-500 (Thymosin Beta-4): promotes angiogenesis; Phase 1 human safety data only. See TB-500 thymosin beta-4 tissue repair science and our BPC-157 vs TB-500 comparison.

Comparison Chart

FAQ's

Is ARA-290 a steroid or SARM?

No. ARA-290 (cibinetide, CAS 1208243-50-8) is a non-hormonal, non-anabolic 11-amino-acid peptide derived from erythropoietin. It targets tissue repair without affecting testosterone or muscle mass. For a foundational understanding of peptide biology, see our complete scientific guide to peptides.

Can you buy ARA-290 legally?

It is unapproved for human use by the FDA, EMA, and TGA Australia, and is sold only as a research chemical. Review ARA-290 shop availability and purity data on our platform.

Does ARA-290 increase red blood cells?

No. Unlike EPO, it does not activate the erythropoietic receptor homodimer, and hemoglobin was unchanged in the human trials (PNAS, 2008). This is the entire design rationale for the compound.

How fast do results appear?

The published trials ran 28-day courses and did not report meaningful changes in the first week. Nerve regeneration is inherently slow, and the structural endpoints that improved were measured at the end of a 28-day course, not within days. Claims of results in 7–14 days are not supported by the trial data.

Is ARA-290 the same as cibinetide?

Yes. ARA-290 is the developmental code assigned by Araim Pharmaceuticals; cibinetide is the international nonproprietary name assigned later for clinical and regulatory use. Both refer to the same peptide (CAS 1208243-50-8). Vendor listings using other suffixed variations of the name are not describing a different compound — check the sequence and mass, not the label.

Do I need post-cycle therapy (PCT)?

Not applicable. ARA-290 does not suppress the HPTA or alter hormone production.

What the Research Team Says About ARA-290

The Design Rationale: Brines and Cerami

The central published claim from ARA-290's developers is a structural one: EPO's tissue-protective and erythropoietic functions are mediated by different receptors, and the tissue-protective signal can therefore be isolated in a short peptide that leaves red-cell production untouched. Their PNAS 2008 paper delimited those protective domains to short sequences — the work that produced ARA-290.

What the Trial Investigators Concluded

The Leiden and Cleveland Clinic investigators who ran the sarcoidosis program concluded that ARA-290 appeared safe and able to reduce neuropathic symptoms, with the later dose-ranging trial adding objective evidence of nerve fiber regrowth. Their own reporting is explicit that pain scores did not separate from placebo in the dose-ranging trial and that the trials were exploratory.

The Honest Reading

ARA-290 has better human evidence than most gray-market peptides — two randomized trials with objective structural endpoints is more than BPC-157, TB-500, or Epithalon can claim. It also has no Phase 3 data, no approval anywhere, and a development program that stopped. Both statements are true at once, and neither should be dropped when the compound is discussed.

When to Stop or Consult a Doctor

Discontinuation Triggers

38. No improvement after a 28-day course

39. Development of allergic reaction (rash, swelling)

40. Unexpected neurological symptoms

Medical Consultation Recommended If

41. History of autoimmune disease

42. History of malignancy — chronic activation of a repair-and-survival receptor is uncharacterized in this setting

43. Taking immunomodulatory drugs

44. Planning surgery or pregnancy

Neuropathy is a symptom of an underlying condition, and undiagnosed progressive neuropathy warrants a clinical workup rather than self-treatment.

Whether you are exploring tissue-protective peptides for neuropathy, healing compounds for injury recovery, or immune-modulating peptides for chronic inflammation, the quality of your source determines your outcomes. Browse our complete peptide guide with 118 compounds, compare shops through independent lab tests, and review community-verified shop reviews.

This article is for educational and informational purposes only and does not constitute medical advice. Peptides discussed may be investigational compounds not approved by the FDA (or equivalent regulators in your jurisdiction) for human use. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.