ARA-290

ARA-290  Reconstitution & BAC Water Research Guide

ARA-290 is an 11-amino-acid, non-erythropoietic peptide derived from the helix-B region of erythropoietin and studied for activation of tissue-protective signaling through the innate repair receptor. Human research has investigated ARA-290 particularly in neuropathy and metabolic settings, but it remains an investigational compound rather than an FDA-approved therapeutic product.

Research Compound Non-Erythropoietic Peptide Not FDA-Approved
ARA-290 peptide research illustration Stylized scientific illustration showing ARA-290 as a short peptide derived from the helix-B region of erythropoietin and associated with innate repair receptor research. EPO STRUCTURE HELIX B ARA-290 / pHBSP
Simplified scientific illustration — ARA-290 is derived from the helix-B region of erythropoietin. It is not a molecular structure rendering.
ARA-290 Research Snapshot
Compound
ARA-290
Cibinetide / pHBSP
Compound Class
11-amino-acid peptide
Research Category
Tissue protection, neuropathy & inflammation research
Regulatory Status
Investigational / Not FDA-Approved
Human Evidence
Limited clinical research
Documented Trial Amounts
1–8 mg/day in selected clinical protocols
Last Reviewed
September 11, 2026

How Much BAC Water for ARA-290?

There is no single scientifically established BAC-water volume that applies to every ARA-290 vial. The amount of liquid changes the resulting concentration, while the total amount of ARA-290 represented by the vial remains unchanged.

Concentration (mg/mL) = Total ARA-290 (mg) ÷ Liquid Volume (mL)

Because authoritative sources reviewed for this page do not establish a universal ARA-290 research vial size or a universal BAC-water reconstitution instruction, the examples below use 5 mg and 10 mg hypothetical vial quantities solely for concentration mathematics.

Mathematical ARA-290 concentration examples
Illustrative Vial Quantity 1 mL 2 mL 2.5 mL 3 mL 5 mL
5 mg 5 mg/mL 2.5 mg/mL 2 mg/mL 1.67 mg/mL 1 mg/mL
10 mg 10 mg/mL 5 mg/mL 4 mg/mL 3.33 mg/mL 2 mg/mL
Important: These are mathematical concentration examples only. They are not manufacturer instructions, clinical doses, FDA-approved dosages, or BacScience recommendations.

How Much BAC Water Should Be Added to ARA-290?

The scientifically correct answer depends on the total ARA-290 quantity and the concentration required by the applicable research protocol. There is no universal BAC-water volume that can be presented as the correct amount for every ARA-290 vial.

Quick answer For concentration mathematics, divide the total amount of ARA-290 in the vial by the liquid volume. For example, a hypothetical 5 mg quantity combined with 2 mL of liquid corresponds mathematically to 2.5 mg/mL. This calculation does not establish that 2 mL is an appropriate reconstitution volume for any particular product or study.

How much BAC water for ARA-290 5 mg?

For a hypothetical 5 mg quantity, the mathematical concentration is 5 mg/mL with 1 mL, 2.5 mg/mL with 2 mL, 2 mg/mL with 2.5 mL, 1.67 mg/mL with 3 mL, and 1 mg/mL with 5 mL.

How much BAC water for ARA-290 10 mg?

For a hypothetical 10 mg quantity, the mathematical concentration is 10 mg/mL with 1 mL, 5 mg/mL with 2 mL, 4 mg/mL with 2.5 mL, 3.33 mg/mL with 3 mL, and 2 mg/mL with 5 mL.

How does BAC-water volume change ARA-290 concentration?

Holding the peptide quantity constant, increasing the liquid volume decreases the concentration. Decreasing the liquid volume increases the concentration. The total mass of ARA-290 represented by the vial does not change simply because the liquid volume changes.

How do you calculate ARA-290 concentration?

Use: concentration = total peptide quantity ÷ liquid volume. Always keep the units consistent. A quantity in milligrams divided by a volume in milliliters produces mg/mL.

What Is ARA-290?

ARA-290, also known as cibinetide or pyroglutamate helix-B surface peptide (pHBSP), is an 11-amino-acid peptide engineered from the three-dimensional structure of erythropoietin (EPO). Unlike EPO itself, ARA-290 was designed to selectively engage tissue-protective signaling rather than the classical erythropoietic EPO receptor pathway.

Research describes the relevant target as the innate repair receptor (IRR), involving the erythropoietin receptor and the common beta receptor/CD131. Experimental work has examined anti-inflammatory, cytoprotective and tissue-repair signaling. :contentReference[oaicite:1]{index=1}

Entity definition

ARA-290 = cibinetide = pHBSP in the research literature. It is a short, non-erythropoietic peptide derived from EPO structure and investigated as an activator of tissue-protective signaling.

ARA-290 innate repair receptor research pathway Simplified pathway illustration showing ARA-290 interaction with an innate repair receptor and downstream tissue-protective research concepts including anti-inflammatory and cytoprotective signaling. ARA-290 RESEARCH SIGNALING ARA-290 pHBSP / cibinetide INNATE REPAIR RECEPTOR EPOR / CD131 signaling concept CELLULAR RESPONSE CYTOPROTECTIVE research endpoints REPAIR / anti-inflammatory research Simplified research schematic — not a complete molecular pathway.
Simplified research schematic of the tissue-protective signaling concept investigated with ARA-290. It is not a complete molecular pathway.

How ARA-290 Works

ARA-290 was engineered to reproduce selected tissue-protective properties associated with EPO without activating the classical erythropoietic receptor response. Research describes interaction with an innate repair receptor involving EPOR and CD131/β-common receptor components. :contentReference[oaicite:2]{index=2}

Mechanism

Non-erythropoietic design

ARA-290 was engineered from EPO structure but designed to avoid the classical EPOR homodimer pathway responsible for erythropoiesis.

Target

Innate repair receptor

Experimental literature describes the peptide as a ligand for the tissue-protective receptor complex involving EPOR and CD131.

Research outcome

Tissue protection

Preclinical and clinical research has explored inflammatory, neural and tissue-repair endpoints rather than erythropoietic effects.

What Is ARA-290 Being Studied For?

Research on ARA-290 has focused particularly on conditions involving neuropathy, nerve-fiber loss, inflammation and tissue-protection mechanisms. Human studies have included sarcoidosis-associated small fiber neuropathy and type 2 diabetes-associated neuropathic symptoms. :contentReference[oaicite:3]{index=3}

Human research

Small-fiber neuropathy

Clinical studies have evaluated ARA-290 in people with sarcoidosis-associated small-fiber neuropathy, including measures of neuropathic symptoms and corneal nerve-fiber density.

Human research

Diabetes-associated neuropathy

A phase 2 study investigated ARA-290 in people with type 2 diabetes and painful neuropathic symptoms and reported changes in metabolic and neuropathic endpoints.

Preclinical

Nerve injury & inflammation

Animal studies have examined neuropathic pain, inflammatory signaling and nerve repair mechanisms.

Human Clinical Research

ARA-290 has progressed beyond purely laboratory research into exploratory human trials. However, the available evidence remains limited and does not establish an FDA-approved therapeutic indication or a universally established clinical dose.

What the human evidence actually shows

Randomized and controlled studies have investigated ARA-290 in neuropathy-related populations. For example, a placebo-controlled study in sarcoidosis-associated small-fiber neuropathy reported improvements in neuropathic symptoms and increases in corneal small nerve-fiber density. :contentReference[oaicite:4]{index=4}

A separate phase 2 study in people with type 2 diabetes investigated 4 mg of ARA-290 administered subcutaneously daily for 28 days and reported improvements in several metabolic and neuropathic endpoints. :contentReference[oaicite:5]{index=5}

These results should be interpreted as findings from specific investigational protocols rather than evidence that ARA-290 is an established treatment.

Doses Studied in Published Research

Important: The amounts below are doses reported in research studies. They are not BacScience dosage recommendations, are not individualized medical instructions, and should not be converted into a self-administration protocol.
ARA-290 doses reported in published human and preclinical research
Study Population Dose Studied Route Frequency Duration Key Finding
Brines et al., 2012 Sarcoidosis + small-fiber neuropathy 2 mg IV 3× weekly 4 weeks Exploratory improvements in neuropathic symptom measures.
Brines et al., 2015 Type 2 diabetes with neuropathic symptoms 4 mg SC Daily 28 days Changes in metabolic and neuropathic endpoints were reported.
NCT02039687 Sarcoidosis + small-fiber neuropathy 1 mg, 4 mg, or 8 mg SC Daily 28 days Phase 2 dose-ranging study evaluating nerve-fiber and neuropathy-related outcomes.
Swartjes et al., 2014 Rat neuropathic pain model 3, 10, 30, 60 µg/kg Experimental Days 1, 3, 6, 8, 10 20-week observation Dose-response reduction in mechanical allodynia in the animal model.

The ClinicalTrials.gov record for NCT02039687 describes 1 mg, 4 mg and 8 mg daily subcutaneous treatment arms for 28 days. :contentReference[oaicite:6]{index=6}

Preclinical Research

ARA-290 has been studied extensively in experimental models. These findings provide mechanistic and hypothesis-generating evidence but should not be treated as equivalent to human clinical evidence.

Animal research

Neuropathic pain

In rat nerve-injury models, ARA-290 was studied at multiple microgram-per-kilogram doses and produced prolonged reductions in mechanical allodynia in the experimental setting. :contentReference[oaicite:7]{index=7}

Animal research

Nerve injury

Experimental work has investigated ARA-290 in peripheral nerve injury and inflammatory pathways, including Schwann-cell and NLRP3-related mechanisms. :contentReference[oaicite:8]{index=8}

Experimental mechanism

Tissue protection

Experimental literature describes signaling associated with cytoprotection, inflammation modulation and tissue repair. :contentReference[oaicite:9]{index=9}

ARA-290 Research Reconstitution & Concentration

Reconstitution mathematics and experimental dosing are two separate concepts. A research protocol may specify an amount of peptide to be administered, while reconstitution determines the concentration of the resulting solution.

Concentration = Total Vial Quantity ÷ Liquid Volume

Worked example: hypothetical 5 mg ARA-290 quantity

  • 5 mg ÷ 1 mL = 5 mg/mL
  • 5 mg ÷ 2 mL = 2.5 mg/mL
  • 5 mg ÷ 2.5 mL = 2 mg/mL
  • 5 mg ÷ 3 mL = 1.67 mg/mL
  • 5 mg ÷ 5 mL = 1 mg/mL

Worked example: hypothetical 10 mg ARA-290 quantity

  • 10 mg ÷ 1 mL = 10 mg/mL
  • 10 mg ÷ 2 mL = 5 mg/mL
  • 10 mg ÷ 2.5 mL = 4 mg/mL
  • 10 mg ÷ 3 mL = 3.33 mg/mL
  • 10 mg ÷ 5 mL = 2 mg/mL
Mathematical concentration is not a dosing recommendation

A calculated concentration does not tell you how much ARA-290 should be used, what route should be used, how frequently it should be administered, or whether bacteriostatic water is an appropriate diluent for a particular product.

BAC Water vs. ARA-290 Concentration

Bacteriostatic water is a diluent formulation, while concentration describes the quantity of compound represented per unit of liquid. These concepts should not be treated as interchangeable.

More liquid

Lower concentration

Increasing liquid volume while keeping the peptide quantity constant produces a lower mg/mL concentration.

Less liquid

Higher concentration

Decreasing liquid volume while keeping the peptide quantity constant produces a higher mg/mL concentration.

Product-specific

Check documentation

The actual product label, certificate of analysis, formulation documentation and applicable research protocol take precedence over generic concentration examples.

ARA-290-specific limitation

The authoritative sources reviewed for this page do not establish a universal ARA-290 instruction stating that a particular number of milliliters of bacteriostatic water should be used for every vial. Therefore this page deliberately does not invent one.

ARA-290 Research Limitations & Safety

ARA-290 has human clinical research behind it, but the evidence should not be confused with regulatory approval or an established clinical treatment indication.

FDA / regulatory status

FDA's September 2024 update to its 503A bulk-substance categories lists Cibinetide (ARA-290) under Category 3, described as bulk drug substances nominated without adequate support. :contentReference[oaicite:10]{index=10}

The FDA Substance Registration System identifies ARA-290, ARA290 and cibinetide, but FDA specifically notes that assignment of a UNII does not imply regulatory review or approval. :contentReference[oaicite:11]{index=11}

Important research limitations

  • Published human studies are relatively limited compared with established medicines.
  • Trial populations, routes, doses and endpoints vary between studies.
  • Experimental findings in animal models cannot automatically be translated into human treatment recommendations.
  • A published clinical-study dose is not the same thing as an FDA-approved dosage.
  • A mathematical reconstitution concentration is not evidence of a medically appropriate concentration.
  • Product identity, purity, sterility, formulation and storage characteristics must be evaluated separately from concentration mathematics.

Frequently Asked Questions About ARA-290

How much BAC water should be added to ARA-290?

There is no universal scientifically established BAC-water volume for every ARA-290 vial. The appropriate concentration depends on the actual peptide quantity and the applicable product or research protocol. Use concentration mathematics rather than assuming a universal volume.

How much BAC water for 5 mg of ARA-290?

A 5 mg quantity would mathematically correspond to 5 mg/mL at 1 mL, 2.5 mg/mL at 2 mL, 2 mg/mL at 2.5 mL, 1.67 mg/mL at 3 mL, and 1 mg/mL at 5 mL. These are concentration calculations only, not recommended reconstitution volumes.

How much BAC water for 10 mg of ARA-290?

A hypothetical 10 mg quantity would mathematically correspond to 10 mg/mL at 1 mL, 5 mg/mL at 2 mL, 4 mg/mL at 2.5 mL, 3.33 mg/mL at 3 mL, and 2 mg/mL at 5 mL.

What is the ARA-290 concentration formula?

Concentration in mg/mL equals total peptide quantity in mg divided by liquid volume in mL.

Does adding more BAC water reduce ARA-290 concentration?

Yes. If the total peptide quantity stays constant, increasing liquid volume reduces the concentration expressed in mg/mL.

Is ARA-290 the same as cibinetide?

Yes. ARA-290, ARA290 and cibinetide are names associated with the same research compound. FDA's Substance Registration System lists these synonyms. :contentReference[oaicite:12]{index=12}

Is ARA-290 FDA approved?

ARA-290 is not presented here as an FDA-approved drug product. FDA's 2024 503A update lists Cibinetide (ARA-290) in Category 3, concerning bulk substances nominated without adequate support. :contentReference[oaicite:13]{index=13}

What doses of ARA-290 have been studied in humans?

Published studies have investigated several regimens, including 2 mg three times weekly intravenously in one exploratory sarcoidosis study, 4 mg subcutaneously daily for 28 days in a type 2 diabetes study, and 1, 4 or 8 mg daily subcutaneous arms in ClinicalTrials.gov study NCT02039687. These are historical research-study doses, not BacScience recommendations. :contentReference[oaicite:14]{index=14}

Is there an established human dose for ARA-290?

No clinically established human dose has been identified from the evidence reviewed for this educational page. Published clinical-study doses should not be treated as an approved therapeutic regimen.

Is ARA-290 the same as erythropoietin?

No. ARA-290 is a short peptide engineered from the structure of erythropoietin and designed to selectively engage tissue-protective signaling rather than the classical erythropoietic pathway. :contentReference[oaicite:15]{index=15}

Can a published ARA-290 dose determine how much BAC water to use?

No. A clinical-study dose and a reconstitution volume answer different questions. Reconstitution determines concentration; the research protocol determines the experimental amount used.

Does BacScience recommend an ARA-290 treatment dose?

No. This page is an educational research and concentration reference. It does not prescribe, recommend or establish a human treatment dose for ARA-290.

Explore More BacScience Research Resources

BAC Water Calculator → Calculate concentration from custom peptide quantities and liquid volumes. Research Compound Library → Explore research compounds and scientific reference pages. Peptide Research Library → Browse peptide research, mechanisms and concentration references. Testing & Transparency → Learn about testing, documentation, identity and research-quality standards.
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Scientific References

Brines M, et al. — ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes.
Molecular Medicine. 2015;20(1):658–666. PMID: 25387363. DOI: 10.2119/molmed.2014.00215.
Brines M, et al. — ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density.
Published randomized controlled clinical research. PMID: 24136731.
Brines M, et al. — Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy.
Molecular Medicine. 2012. PMID: 23168581. DOI: 10.2119/molmed.2012.00332.
Swartjes M, et al. — ARA 290, a peptide derived from the tertiary structure of erythropoietin, produces long-term relief of neuropathic pain coupled with suppression of the spinal microglia response.
Molecular Pain. 2014;10:13. PMID: 24529189.
Brines M, et al. — Flipping the molecular switch for innate protection and repair of tissues.
Review of pHBSP / ARA-290 mechanism, pharmacology and tissue protective signaling. PMID: 25728128.
ClinicalTrials.gov — NCT02039687
Phase 2 dose-ranging study of ARA-290 in sarcoidosis-associated small-fiber neuropathy.
U.S. Food and Drug Administration — 503A Categories Update, September 27, 2024
Lists Cibinetide (ARA-290) under Category 3: bulk drug substances nominated without adequate support.
U.S. Food and Drug Administration — Substance Registration System, ARA-290 / Cibinetide
Identity and synonym information; FDA notes that a UNII does not imply regulatory review or approval.

Last Scientifically Reviewed

Last scientifically reviewed: September 11, 2026

Research scope: PubMed / NIH, ClinicalTrials.gov and FDA regulatory sources.

Reviewer: BacScience Scientific Content Review Team

This page should be reviewed again when significant new human trials, regulatory decisions, formulation information or authoritative reconstitution documentation become available.
Educational and research notice:

This page is provided for scientific education and research reference. It does not provide medical diagnosis, treatment instructions, individualized dosing, or a recommendation to use ARA-290. Published research doses are presented solely as historical study information. Mathematical concentration examples are not product-specific reconstitution instructions.

Always distinguish between a mathematical concentration, an experimental research dose, an FDA-approved dosage and an anecdotal or community protocol. These are not interchangeable.