ARA-290

Sarcoidosis is a systemic inflammatory disease characterized by granuloma formation, most commonly in the lungs but affecting multiple organs including peripheral nerves. Small fiber neuropathy is the most common peripheral neurological complication of sarcoidosis, causing burning pain, numbness, allodynia, and autonomic dysfunction. Current treatment — primarily immunosuppression — is largely ineffective for SFN symptoms. Two Phase 2 trials specifically addressed this population.

Trial 1 (Heij et al., Molecular Medicine, 2012) [4]: Randomized, double-blind, placebo-controlled, n=22 sarcoidosis patients with SFN. Protocol: 2 mg IV ARA-290 three times weekly x 4 weeks. Primary endpoint: Small Fiber Neuropathy Screening List (SFNSL) score and Brief Pain Inventory (BPI). Results: Statistically significant improvement in SFNSL score, driven primarily by autonomic symptom improvement (dry eyes, orthostatic symptoms, blurred vision). Quality of life and depressive symptom scales also improved. No safety signals; no hematological adverse effects.

Trial 2 (Dahan et al., Molecular Medicine, 2013): Randomized, double-blind, placebo-controlled, n=40 sarcoidosis patients with SFN. Protocol: 4 mg SubQ ARA-290 daily x 28 days. Primary endpoints: SFNSL score AND corneal nerve fiber density (CNFD) by confocal microscopy. Results: Statistically significant reduction in SFNSL neuropathic symptom scores. Statistically significant 23% increase in corneal nerve fiber area — objective, structural nerve regeneration. No safety signals. The 4 mg SubQ daily protocol from this trial is the basis for community dosing. Grade B for both trials: randomized, double-blind, placebo-controlled; Leiden University Medical Center (independent academic institution, not Araim); small n; single site.

Brines et al. (Molecular Medicine, 2014 [6]; PMC4365069) conducted a randomized, double-blind, placebo-controlled trial of ARA-290 in patients with type 2 diabetes and neuropathic symptoms. Protocol: 1 mg, 4 mg, or 8 mg SubQ daily x 28 days. Results: Clinically meaningful improvements in neuropathic symptom scores (SFNSL) at the 4 mg and 8 mg doses. Additionally — and unexpectedly — significant improvements in metabolic parameters: reduced HbA1c (approximately 0.5% reduction), improved insulin sensitivity, and improved lipid profile. The metabolic improvements were not the primary endpoint but were robust secondary findings. Mechanistically consistent: ARA-290's anti-inflammatory effects reduce the chronic low-grade inflammation that drives insulin resistance in type 2 diabetes. Grade B: randomized, double-blind, placebo-controlled; multi-dose; both neuropathy and metabolic outcomes.

ARA-290 reduces ischemic myocardial infarct size in animal models to an extent comparable to full EPO, without any erythropoietic effects — one of the original validations of the two-receptor-system model. The compound increases the ROS threshold for mitochondrial permeability transition by approximately 40% in cardiac models, providing cellular protection during reperfusion injury. Multiple independent groups have replicated ischemia-reperfusion protection across cardiac, renal, and brain models. Grade C: highly replicated animal models; no human cardiac ischemia trial.

ARA-290 reduces contusion volume from 20.8 mm³ to 5.9 mm³ in a rodent TBI complicated by hemorrhagic shock model — effects comparable to full EPO without thrombotic risk. Multiple stroke models show reduced infarct volume, improved cerebral blood flow, and better neurological function scores after ARA-290 treatment. A 2024 independent study confirmed neuroprotection in MCAO (middle cerebral artery occlusion) stroke models. Grade C: multiple independent groups; replicated; no human TBI or stroke trial.

ARA-290 significantly accelerates wound closure in diabetic animal models — increased wound closure rate, reduced re-epithelialization time, greater collagen content. The mechanism combines anti-inflammatory effects with promotion of angiogenic and repair signaling in the wound microenvironment. Grade C: animal model; one clinical application noted in the Phase 2 diabetes trial outcomes but not a primary wound healing trial.

Two independent groups have demonstrated ARA-290 protects transplanted pancreatic islets by inhibiting macrophage activation and reducing inflammatory damage in the immediate post-transplant period. Beta cell survival in the transplant setting is a critical challenge; ARA-290's macrophage M2-reprogramming and anti-apoptotic signaling are mechanistically relevant. Grade C: two independent animal studies; clinical application in islet transplantation is promising but untested.

Recent preclinical work suggests ARA-290 may have antidepressant and anxiolytic effects through IRR-mediated neuroinflammation reduction. The Phase 2 sarcoidosis trials did show improvement in depression scores (IDS questionnaire) as a secondary endpoint — potentially reflecting both improved neuropathic pain burden and direct neuropsychiatric effects. Grade D: secondary endpoint in human trial; preclinical interest; not a studied indication.

ARA-290 is an 11-amino acid peptide corresponding to the three-dimensional surface geometry of EPO's helix B region: pyroglutamate (pGlu)-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser. Molecular weight approximately 1,257 Da. The N-terminal pyroglutamate is formed by cyclization of glutamine and specifically resists aminopeptidase degradation — a rational design choice that extends the compound's plasma stability compared to the unmodified HBSP sequence. The peptide is engineered to replicate the spatial conformation of EPO's helix B surface, not its primary sequence — meaning the geometric presentation to the IRR receptor binding site is the functional feature, not simple sequence identity.

NAMING DISAMBIGUATION

ARA-290 = Cibinetide = pHBSP (pyroglutamate helix B surface peptide) = HBSP (helix B surface peptide). 'ARA-290' is the Araim Pharmaceuticals research name used in early preclinical and Phase 1 studies. 'Cibinetide' is the INN (international nonproprietary name) assigned as clinical development progressed. 'pHBSP' and 'HBSP' appear in academic literature. All refer to the same compound or closely related forms of the same 11-amino acid sequence. COA mass spec should confirm ~1,257 Da for identity verification.

ARA-290 has a plasma half-life of approximately 20 minutes after subcutaneous injection. This short plasma half-life is a key safety feature built into the compound's design: because the IRR is expressed only at sites of injury or inflammation, the brief window during which ARA-290 is in plasma limits its access to tissues where the receptor isn't expressed. The peptide is at its highest concentrations during the first 30-60 minutes post-injection, accessing the IRR at injury sites during this window and then being cleared. Despite the short plasma half-life, downstream signaling effects — anti-apoptotic gene expression changes, cytokine suppression, neural repair signaling — persist for hours to days after a single dose. Subcutaneous administration is the route used in the successful Phase 2 sarcoidosis trials (4 mg daily x 28 days). Earlier sarcoidosis studies used IV administration (2 mg three times weekly).

Lyophilized ARA-290 is stable at -20C for 18-24 months. Reconstituted with bacteriostatic water: refrigerate at 2-8C; use within 30 days. Solution is clear and colorless. The pyroglutamate N-terminal modification provides better stability than standard linear peptides, but standard cold-chain handling applies. Mass spectrometry confirming ~1,257 Da is the identity check. HPLC purity 99%+ minimum — the 11-amino acid sequence includes glutamine which can deamidate to glutamate on aging, altering receptor binding geometry.

Brines and colleagues' key insight established that EPO operates through two distinct receptor complexes with different tissue distributions and different biological functions. The classical EPO receptor homodimer (EPOR-EPOR): expressed in bone marrow erythroid progenitors, placenta, some tumor cells; drives red blood cell production via JAK2/STAT5 signaling; the target of therapeutic EPO for anemia; the source of EPO's performance-enhancing and cardiovascular side effects. The innate repair receptor (IRR, EPOR/CD131 heterodimer): expressed in neurons, glial cells, macrophages, endothelial cells, cardiac muscle, kidney tubules — primarily in stressed, injured, or inflamed tissue; drives anti-apoptotic, anti-inflammatory, and tissue-repair signaling via distinct kinase cascades from the EPOR homodimer; does not drive erythropoiesis.

This receptor separation means that compounds which selectively engage the IRR without engaging the EPOR homodimer should provide tissue protection without erythropoiesis. The challenge is structural: EPO engages both receptors using the same molecular surface. ARA-290's helix B surface geometry was engineered to fit the IRR while lacking the geometry required for EPOR homodimer engagement. Grade B: the two-receptor model is well-established and is the basis for the clinical program; ARA-290's IRR selectivity is supported by preclinical and clinical data (no erythropoietic signal in any human trial).

The innate repair receptor is expressed constitutively at low levels in most tissues and is upregulated at sites of injury, inflammation, or metabolic stress. This anatomical selectivity means ARA-290's short plasma half-life and restricted receptor expression create a dual safety system: the compound is only present in circulation for ~20 minutes (limiting systemic exposure) and the receptor it activates is only abundant where the compound is needed (limiting off-target effects). When ARA-290 binds the IRR, it initiates several convergent protective pathways: suppression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) through NF-κB pathway modulation; activation of anti-apoptotic cascades (Akt/PI3K, ERK1/2); promotion of neural repair signaling relevant to small fiber nerve regeneration; and macrophage reprogramming from pro-inflammatory (M1) to anti-inflammatory (M2) phenotype. Grade B-C: mechanism confirmed in multiple independent preclinical systems; human clinical data shows consistent anti-inflammatory and neuroprotective outcomes without erythropoietic signal.

The most remarkable clinical finding for ARA-290 is not pain reduction — it is documented nerve regeneration. Small fiber neuropathy (SFN) is characterized by degeneration and loss of the small unmyelinated C fibers and thinly myelinated Aδ fibers that mediate pain, temperature sensation, and autonomic function. These fibers can be directly measured using corneal confocal microscopy — a non-invasive, high-resolution imaging technique that visualizes the subbasal nerve plexus in the cornea, which is composed entirely of small fibers. Corneal nerve fiber density (CNFD) is a validated proxy for systemic small fiber density and a direct measure of nerve fiber abundance.

The Phase 2b trial in sarcoidosis-associated SFN (Dahan et al., 2013 [5]; 40 patients, 4 mg ARA-290 SubQ daily x 28 days, double-blind, placebo-controlled) showed a statistically significant 23% increase in corneal nerve fiber area in ARA-290-treated patients compared to no significant change in placebo. This is not a symptom questionnaire — it is an objective structural measurement of nerve fiber abundance. More nerve fibers. In humans. After 28 days. No other compound in this book has demonstrated this in a controlled human trial. Grade B (randomized, double-blind, placebo-controlled; objective primary endpoint; n=40 single-site; replication needed).

WHY THE CORNEAL NERVE FIBER FINDING MATTERS

Small fiber neuropathy affects millions — diabetic peripheral neuropathy, chemotherapy-induced neuropathy, sarcoidosis, idiopathic. Current standard of care is symptomatic: gabapentin, pregabalin, duloxetine — drugs that reduce pain perception but do nothing for the underlying nerve degeneration. No approved compound has demonstrated reversal of small fiber nerve degeneration in humans. ARA-290's 23% CNFD increase in a controlled trial — documented by confocal microscopy, not questionnaire — is the first controlled human evidence of small fiber nerve regeneration by any pharmacological intervention. If this finding had been followed by a funded Phase 3 trial, ARA-290 might now be the first approved treatment for SFN. Instead, it is a research chemical.

ARA-290 reprograms macrophages from the pro-inflammatory M1 phenotype (characterized by TNF-α, IL-6, IL-12 production) to the anti-inflammatory M2 phenotype (characterized by IL-10, TGF-β, tissue remodeling factors). This macrophage switch is mechanistically relevant to both neuropathy (where M1 macrophages drive neuroinflammation and nerve damage) and sarcoidosis (where granuloma formation is driven by dysregulated macrophage activation). Grade C: preclinical mechanism; consistent with clinical outcomes; not directly characterized in human tissue during ARA-290 trials.

ARA-290 plasma half-life: approximately 20 minutes after SubQ injection. Peak plasma concentrations: 20-40 minutes post-injection. Despite the short plasma half-life, the downstream signaling effects — NF-κB suppression, anti-apoptotic gene expression, cytokine changes — persist for hours to days after a single dose. The dual safety mechanism (short plasma half-life + injury-restricted receptor expression) means ARA-290 is active primarily at injury sites during the injection window, then cleared. SubQ injection achieves adequate tissue distribution and is the route used in the Phase 2b Dahan trial. Earlier IV studies used 2 mg IV three times weekly; the subcutaneous daily protocol is more practical and produced the nerve regeneration finding.

ARA-290: lyophilized powder reconstituted with bacteriostatic water. Solution is clear and colorless. Refrigerate at 2-8C after reconstitution; use within 30 days. Pyroglutamate N-terminus provides stability advantage over standard linear peptides, but cold-chain handling still required. Mass spectrometry confirming ~1,257 Da essential; HPLC purity 99%+ minimum. Note: glutamine residues in the sequence can deamidate to glutamate with heat or extended storage — this chemically alters the peptide and could affect IRR binding geometry. Cold storage is particularly important for ARA-290 in solution.

Vial Size

BAC Water

Concentration

Volume for 4 mg

Notes

10 mg

2.5 mL

4,000 mcg/mL

1.0 mL (100 units)

Standard reconstitution for Phase 2 protocol dose matching

10 mg

5.0 mL

2,000 mcg/mL

2.0 mL

Lower concentration; larger injection volume

5 mg

1.25 mL

4,000 mcg/mL

1.0 mL (full vial)

Smaller vial; 5mg = ~1.25 days at Phase 2 protocol

Protocol

Dose

Frequency

Duration

Evidence Basis

Phase 2 protocol (reference/gold standard)

4 mg

Daily SubQ

28 days

Dahan 2013 Phase 2 RCT — the corneal nerve regeneration trial; this is the dose that showed 23% CNFD increase

Conservative entry

1-2 mg

Daily SubQ

28 days

Brines 2014 diabetes trial also tested 1 mg; lower dose; assess tolerance

Standard community

4 mg

Daily SubQ

4-8 weeks

Most common community protocol; matches Phase 2 evidence

Extended maintenance

2-4 mg

3-5x per week

After initial 28-day course; ongoing

Community extension beyond trial duration; no comparative data

IV protocol (reference)

2 mg

3x/week IV

4 weeks

Heij 2012 trial protocol — less practical; early sarcoidosis data

No specific circadian timing requirement. ARA-290 has no food dependency, no glucose dependency (unlike CJC/Ipa), and no sleep-stage dependency. Most community users inject in the morning as a practical convention. The short plasma half-life means timing precision beyond 'once daily at a consistent time' is not pharmacologically critical. For users with neuropathic pain that is worse at specific times (e.g., evening pain flares), some practitioners suggest afternoon injection — but this is not evidence-based.

Baseline neuropathy symptom scoring (a validated tool like the SFNSL — the Small Fiber Neuropathy Screening List — is free and publicly available) establishes a quantifiable baseline for assessing response. The community's most objective monitoring option for nerve fiber density is corneal confocal microscopy, which is available at specialized neurology and ophthalmology centers. This is not routine and requires referral, but is the measurement that documented nerve regeneration in the Phase 2 trial. For diabetic users: fasting glucose, HbA1c, insulin sensitivity markers (based on the Phase 2 metabolic improvements). No mandatory lab testing; the compound's clean safety profile in clinical trials doesn't generate specific monitoring requirements.

ARA-290 has one of the cleanest safety profiles of any compound in the neuroprotection/anti-inflammatory space. No serious adverse events attributable to ARA-290 have been reported in any published clinical trial, across multiple Phase 1 and Phase 2 studies in healthy volunteers, patients with kidney disease, sarcoidosis patients, and diabetic patients. The compound was designed to minimize off-target effects, and the clinical data bears this out. The dual safety mechanism — short plasma half-life and injury-restricted receptor expression — appears to limit the adverse effect potential that systemically distributed ERythropoietic EPO produces.

• Injection site reactions: mild redness, swelling, or brief burning at the SubQ injection site. Comparable to other daily SubQ injection protocols. Managed with site rotation and cold compress.
• Transient headache: occasionally reported in clinical trial subjects. Mild and transient.
• Mild gastrointestinal discomfort: occasionally reported. Not a prominent adverse effect pattern.
• No erythropoietic effects: critically, no increase in hemoglobin, hematocrit, reticulocyte count, or EPO levels was documented in any human trial — validating the non-erythropoietic design. No polycythemia. No thrombosis signals.

The EPO receptor component of the IRR is expressed on some tumor cell types. ARA-290's anti-apoptotic signaling could theoretically promote survival of cancer cells that express the IRR heterodimer. This is a theoretical concern — not documented harm in the clinical trials, which excluded active malignancy — but warrants careful consideration for anyone with current or recent cancer. Immunogenicity of repeated ARA-290 administration over extended periods (beyond the 28-day trial protocols) has not been fully characterized. As a peptide that mimics part of an endogenous protein (EPO), anti-peptide antibody formation could theoretically produce cross-reactive anti-EPO antibodies — a serious theoretical concern, though no immunogenic signal was observed in published trials.

• Active malignancy: EPO receptor expressed on some tumor cell types; anti-apoptotic signaling could theoretically promote cancer cell survival. Discuss with oncologist before use.
• Pregnancy: no reproductive safety data; avoid.
• Severe renal impairment: pharmacokinetics uncharacterized in severe kidney disease; given EPO's renal production, this is a relevant gap.
• Current EPO use: clinical trial protocols excluded EPO use within 2 months due to potential receptor interference — residual EPO occupancy of the EPOR component of the IRR could alter ARA-290's pharmacodynamics.
• Anticoagulation/coagulation disorders: no specific signal, but the EPO receptor interaction warrants discussion with prescribing physician if on warfarin, direct oral anticoagulants, or with coagulation disorders.

• FDA — No approval, orphan drug designation only: ARA-290/cibinetide received FDA Orphan Drug designation for neuropathic pain in sarcoidosis and FDA Fast Track designation. These are not approvals — they are regulatory incentives and expedited review pathways granted to promising compounds for rare diseases. No Phase 3 trial was ever conducted. No NDA was submitted. Araim Pharmaceuticals has closed. No compounding pharmacy can legally prepare ARA-290 for patient use — it does not appear on the FDA 503A bulk drug substance list. The FDA orphan drug designation technically still exists but has no active holder. Research chemical status only.
• European Medicines Agency — Orphan designation only: similar to US status. Orphan designation granted; no approval.
• Research chemical: ARA-290 is available from peptide research vendors as a research chemical, with the usual quality variation. Not a controlled substance in most jurisdictions. Standard peptide sourcing cautions apply.

WADA STATUS — BANNED UNDER S2 — DESPITE THE DESIGN INTENT

ARA-290 is prohibited under the 2026 WADA Prohibited List, Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). The basis: it activates a receptor complex that includes the EPO receptor subunit. WADA's position is that EPO-related substances capable of activating any EPO receptor system are prohibited due to potential tissue-protective and recovery-enhancing effects in athletes, regardless of whether they produce the erythropoietic performance enhancement that originally led to EPO's ban. The profound irony: ARA-290 was specifically engineered to lack EPO's erythropoietic performance-enhancing effects. It does not raise hemoglobin. It does not increase red blood cells. It does not produce the cardiovascular performance benefit that made EPO the most notorious doping agent in cycling. And WADA banned it anyway. Athletes subject to WADA testing may not use ARA-290. This is a hard stop.

BPC-157 promotes angiogenesis, tendon/ligament healing, gut mucosal repair, and has some evidence for nerve healing through VEGF-related mechanisms. TB-500 drives actin migration and cell motility relevant to tissue repair. ARA-290 specifically addresses the inflammatory environment and small fiber nerve regeneration that BPC-157 and TB-500 don't directly target. For users with nerve injuries, chronic neuropathic pain, or conditions involving both structural damage and neuropathic components (e.g., diabetic foot complications, post-surgical nerve damage), the combination addresses different dimensions: structural repair (BPC-157/TB-500) and neural regeneration in an anti-inflammatory environment (ARA-290). No pharmacological conflicts; no interaction data.

SS-31 addresses the mitochondrial structural dimension of cellular dysfunction — cardiolipin stabilization, ETC efficiency. ARA-290 addresses the inflammatory and apoptotic dimension — IRR-mediated cytoprotection, nerve regeneration. In neurological conditions with both mitochondrial dysfunction and neuroinflammatory components (post-TBI, neurodegenerative conditions, aging neuropathy), the two mechanisms are genuinely complementary. The community uses this combination as a 'comprehensive neuroprotection' stack. No pharmacological conflicts; no interaction data.

GHK-Cu drives collagen synthesis, angiogenesis, and ECM quality in skin and connective tissue. ARA-290 reduces the inflammatory burden that impairs wound healing and peripheral nerve function. For diabetic wound healing — where both inflammatory dysregulation and impaired connective tissue repair are present — the combination addresses both deficits. No pharmacological conflicts.

Clinical trial protocols excluded EPO use within 2 months before ARA-290 treatment. Residual EPO bound to the EPOR component of the IRR could theoretically alter ARA-290's ability to engage the IRR heterodimer. The interaction mechanism is speculative, but the trial exclusion criterion is documented. Avoid combining ARA-290 with therapeutic EPO.

Unlike most compound timelines in this book (which are community-derived Grade E), ARA-290's timeline is partly anchored in Phase 2 trial data. The Phase 2 sarcoidosis trial ran 28 days and documented the following pattern:

Timeframe

Evidence-Based Expectations (Grade B for sarcoidosis SFN; Grade E for general community)

Week 1-2

Neuropathic symptom improvement beginning — particularly autonomic symptoms (dry eyes, orthostatic symptoms) in sarcoidosis trial. Community users report pain score reductions starting in this window. Injection site reactions most prominent in first week.

Week 2-4

Peak clinical response window per trial data. Neuropathic pain scores at maximum improvement. Autonomic function improvements consolidated. The corneal nerve fiber density increase documented in the trial became measurable in this window (though confocal microscopy wasn't performed sequentially during the trial — the 28-day endpoint showed the 23% increase).

Week 4-8 (community extension)

Community users report sustained improvements extending beyond the 28-day trial window. No comparative data for 4-8 week courses vs 28-day courses.

Post-course (months)

The trial data showed durable effects — neuropathy symptom improvements persisted at follow-up beyond the 28-day course. This persistence is consistent with structural nerve regeneration (once nerve fibers grow back, the benefit persists without continued drug) rather than purely pharmacological symptom masking.

Based on the Phase 2 evidence, ARA-290 shows the most compelling benefit in:

• Sarcoidosis-associated small fiber neuropathy: the most directly evidence-supported population. If you have sarcoidosis and SFN symptoms, this is the compound with the best controlled human evidence for your specific condition in the entire longevity/peptide space.
• Diabetic peripheral neuropathy: Phase 2 evidence for both neuropathic symptom improvement and metabolic benefit (HbA1c, insulin sensitivity). This population is large and underserved by current standard of care.
• Any small fiber neuropathy (idiopathic, chemotherapy-induced, other causes): mechanistically, the IRR-mediated nerve regeneration signal should operate regardless of the underlying cause of SFN. The Phase 2 data is in sarcoidosis and diabetes, but community use extends to all-cause neuropathy.
• Post-injury neuroprotection: the ischemia-reperfusion animal data and TBI models suggest utility in the post-injury period for minimizing secondary neurological damage. Community use includes post-surgical nerve injury, post-TBI, and stroke recovery.

• Using ARA-290 while on WADA testing: S2 explicit ban — WADA prohibits it as an EPO-related substance. Not a grey area. An athlete who tests positive for ARA-290 or cibinetide faces a doping violation.
• Not matching the Phase 2 protocol dose: the 4 mg/day SubQ x 28 days protocol is the evidence-anchored dose. Using 1 mg/day or every-other-day dosing with 'the science supports it' reasoning is moving away from the studied protocol without evidence that lower doses or less frequent dosing produce the same outcomes.
• Expecting EPO-like performance enhancement: ARA-290 does not raise red blood cells. It does not improve aerobic capacity through hematological mechanisms. It does not produce the cardiovascular performance benefit that EPO produces. Anyone using it for athletic performance enhancement is misunderstanding the mechanism — and will be WADA positive for a compound that isn't giving them the benefit they thought.
• Combining with EPO: documented exclusion criterion in trials. Avoid.
• Sourcing without COA: the 11-amino acid sequence with pyroglutamate N-terminus and specific glutamine residues requires verified synthesis. A truncated or chemically degraded ARA-290 (deamidated glutamine → glutamate) has different receptor binding geometry. HPLC purity 99%+ and mass spec at ~1,257 Da are non-negotiable.

The Phase 2 trial used a defined 28-day course. There is no evidence base for continuous indefinite use. Community practice: 28-day courses followed by 4-8 week breaks, repeated as needed. The biological rationale for cycling: nerve fiber regeneration, once achieved, should persist without continued drug treatment (structural change, not pharmacological masking). The inflammatory suppression effects would fade after drug cessation, suggesting periodic courses for conditions with ongoing inflammation. This cycling approach is consistent with the trial design and is mechanistically defensible.

ARA-290 is one of the less commonly available compounds in the research peptide space — significantly fewer vendors carry it than BPC-157, TB-500, or GHK-Cu. This scarcity reflects both lower demand and higher synthesis difficulty (11-amino acid sequence with pyroglutamate N-terminus). Pricing 2026: research vendor (HPLC + MS + endotoxin COA), 10 mg ARA-290: $80-150. Quality requirements are higher than for simpler peptides: pyroglutamate N-terminus synthesis must be verified (not just assumed from the molecular weight); glutamine deamidation is a real stability concern that means older stock or improperly stored product may have chemically altered residues; endotoxin testing below 0.1 EU/mg for injectable use. The closure of Araim Pharmaceuticals has not meaningfully affected the research chemical supply chain, but it has eliminated any prospect of pharmaceutical-grade ARA-290 becoming available through clinical channels in the near term.

ARA-290 attracts a more medically specific community than most peptides in this book. Its users are disproportionately people with diagnosable neuropathic conditions — diabetic neuropathy, chemotherapy-induced peripheral neuropathy, idiopathic small fiber neuropathy, post-herpetic neuralgia — for whom conventional treatments (gabapentin, pregabalin, duloxetine) have provided insufficient relief. This is a different profile from the general biohacking longevity community. The community is smaller but unusually medically literate, partly because the underlying conditions require medical engagement and partly because the Phase 2 evidence is accessible and specific enough to attract users who understand what they're treating.

Community consensus: neuropathic pain improvement within 1-2 weeks of starting the 4 mg/day protocol, with the most significant gains in the 2-4 week window. Autonomic symptoms (which were particularly responsive in the sarcoidosis trial) show improvement that some community users describe as more noticeable than pain relief. Post-course durability of at least weeks to months — consistent with the structural nerve regeneration hypothesis. The compound is notably absent from the broader fitness and anti-aging biohacking community, which is appropriate given its mechanism — it is not an anti-aging compound in the MOTS-c or FOXO4-DRI sense. It is a nerve repair and anti-inflammatory compound.

Brines M, Bhardwaj R, Bhardwaj N, et al. (2003). Erythropoietin mediates tissue protection through an erythropoietin and common beta-subunit heteroreceptor. PNAS. 101(41):14907-12. [THE foundational paper establishing the two-receptor model — EPOR homodimer vs IRR heterodimer; hematopoietic and tissue-protective activities separable]

Brines ML, Ghezzi P, Keenan S, et al. (2004) [2]. Erythropoietin crosses the blood-brain barrier to protect against experimental brain injury. PNAS. [IRR in the CNS; neuroprotection by EPO via non-erythropoietic mechanism]

Brines M, Patel NS, Villa P, et al. (2008) [3]. Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. PNAS. 105(31):10925-30. [Design of helix B surface peptides including pHBSP/ARA-290; preclinical validation across ischemia, inflammation, neuropathy models]

Heij L, Niesters M, Swartjes M, et al. (2012). Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy: a randomized, double-blind pilot study. Molecular Medicine. 18(12):1507-13. PMC3563705. [Phase 2 RCT, n=22, sarcoidosis-SFN, IV ARA-290 2 mg 3x/week x 4 weeks; significant SFNSL improvement; no safety signal; Leiden University Medical Center — independent]

Dahan A, Dunne A, Swartjes M, et al. (2013). ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density. Molecular Medicine. 19:334-345. [Phase 2 RCT, n=40, sarcoidosis-SFN, 4 mg ARA-290 SubQ daily x 28 days; significant pain reduction AND 23% CNFD increase — THE nerve regeneration finding; objective primary endpoint; Leiden University Medical Center]

Brines M, Dunne AN, van Velzen M, et al. (2014). ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes. Molecular Medicine. 20:658-666. PMC4365069. [Phase 2 RCT, multiple doses, T2D with neuropathy; SFNSL improvement + HbA1c reduction + improved insulin sensitivity]

Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain. IOVS. 2017. [Extension of the corneal nerve fiber finding; confirmatory analysis; ARVO journal]

PMC10941562 (2024) [7]. Erythropoietin-derived peptide ARA290 mediates brain tissue protection through the β-common receptor in mice with cerebral ischemic stroke. [Independent Chinese academic group; 2024 stroke model confirmation; mechanism via βCR confirmed independently]

Araim Pharmaceuticals. FDA Orphan Drug designation: neuropathic pain in sarcoidosis. FDA Fast Track designation. EMA Orphan Drug designation for sarcoidosis. Phase 3 trials announced Q4 2015 — never initiated. Company closed operations by 2026. No active IND or NDA.

WADA. (2026). Prohibited List S2: Peptide Hormones, Growth Factors, Related Substances and Mimetics. ARA-290/cibinetide covered as EPO-related substance activating EPO receptor complex. Prohibited at all times.

Well-suited for: adults with documented small fiber neuropathy from any cause (sarcoidosis, diabetes, chemotherapy, idiopathic) who have inadequate pain control with conventional treatments; patients with autonomic dysfunction associated with small fiber involvement; users seeking nerve repair support following injury, surgery, or inflammatory insult; the medically engaged user who has read the Phase 2 trials and is making an informed choice to use a compound that demonstrated efficacy in their specific condition in controlled human data.

Extra caution for: anyone with active malignancy or recent cancer history (EPO receptor anti-apoptotic signaling concern); anyone on EPO or who has used EPO within 2 months (receptor interference); severe renal impairment (uncharacterized pharmacokinetics).

Not appropriate for: any competitive athlete under WADA testing (S2 explicit ban — not a grey area); anyone expecting athletic performance enhancement through hematological mechanisms (ARA-290 does not raise red blood cells at any dose); anyone treating diagnosable neuropathic conditions without physician involvement — the underlying conditions that create the strongest rationale for ARA-290 (sarcoidosis-SFN, diabetic neuropathy) require physician oversight regardless of what compound is being used.

Feature

ARA-290

Gabapentin/Pregabalin

Duloxetine

Mechanism

IRR activation — nerve regeneration + anti-inflammation

GABA-A/voltage-gated calcium channel — symptom masking

Serotonin-norepinephrine reuptake inhibition — pain modulation

Nerve regeneration

23% CNFD increase in controlled trial

None documented

None documented

Primary evidence

Phase 2 RCT (disease-modifying)

Multiple RCTs (symptom-modifying)

Multiple RCTs (symptom-modifying)

FDA approval

None

Yes (various indications)

Yes (diabetic neuropathy)

Dependence/withdrawal

None documented

Significant physical dependence risk

Significant discontinuation syndrome

Cognitive side effects

None documented

Significant (sedation, cognitive fog)

Moderate

Access

Research chemical only

Prescription; widely available

Prescription; widely available

WADA status

Banned S2

Not banned

Not banned

• 'EPO-related' means performance-enhancing: ARA-290 is related to EPO by structure, not by mechanism. It does not increase red blood cells. It does not improve VO2 max. It does not produce the performance-enhancing hematological effects that made EPO the most notorious doping agent in sport. The WADA ban is based on receptor classification, not demonstrated performance enhancement.
• Orphan Drug designation means the FDA approved it: FDA Orphan Drug designation is a regulatory incentive (tax credits, market exclusivity period, expedited review) for promising compounds targeting rare diseases. It is not approval. It does not reflect a safety or efficacy determination. Many compounds receive orphan designation and never reach approval.
• Phase 2 success predicts Phase 3 success: approximately 50% of compounds that succeed in Phase 2 fail in Phase 3. The 23% CNFD finding in 40 patients at a single site needs replication in a larger, multisite, Phase 3 trial to constitute regulatory-grade evidence. The finding is real and compelling. It is not proven in the Phase 3 sense.
• Araim closing means the science was wrong: Araim Pharmaceuticals closed due to funding gaps, not scientific failure. The investigators themselves have stated the development stalled due to commercial reasons rather than scientific reasons. This is documented in the literature. A company failing to secure Phase 3 funding reflects the economics of rare disease drug development, not a verdict on the compound's efficacy.

— End of ARA-290 —

THE PEPTIDE BIBLE | ARA-290 (Cibinetide) | For Research & Educational Purposes Only