Orexin B - Front - MiPeptidos
Cognitive / Neuropeptides

Orexin B

CAS: 205640-91-1

Orexin B is a research peptide in the cognitive / neuropeptides category. Orexin B is a 28-amino acid neuropeptide co-expressed with Orexin A in lateral hypothalamic neurons. MiPeptidos offers Orexin B in 2 sizes with 99.1% verified purity and full analytical documentation.

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$51.95/vial
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≥99% Purity
COA Included
Third-Party Tested
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CoA Included
HPLC Verified
GMP Compliant
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How Orexin B Works

Orexin B is a 28-amino acid neuropeptide co-expressed with Orexin A in lateral hypothalamic neurons. Unlike Orexin A (which binds both OX1R and OX2R equally), Orexin B preferentially binds OX2R with ~10-fold selectivity over OX1R. It promotes wakefulness primarily through OX2R-mediated arousal pathways, regulates REM sleep, modulates autonomic functions, and influences glucose homeostasis. It has less potent effects on feeding compared to Orexin A.

Research Applications

1
OX2R-selective orexin signaling
2
REM sleep regulation
3
Narcolepsy treatment research
4
Autonomic nervous system modulation
5
OX1R vs OX2R receptor pharmacology
View Published Research on PubMed →

Pricing

SizePer Vial10-Pack
5mg
$51.95$378.95
10mgBest Value
$92.95$678.95

Prices shown per vial from 10-pack. Volume discounts available for 50+ vials — contact us.

HPLC Purity Analysis

High-Performance Liquid Chromatography
99.1%purity
mAURetention Time (min)0250500750100005101520253099.1%
Method: RP-HPLC C18 ColumnDetection: UV 220nmMobile Phase: Acetonitrile/Water + 0.1% TFA

Certificate of Analysis

MiPeptidos
Orexin B
PASSES ALL SPECIFICATIONS
Batch NumberHR-RXNB-2600315
Date of AnalysisJanuary 17, 2026
Purity (HPLC)99.1%
AppearanceWhite to off-white lyophilized powder
SolubilityFreely soluble in sterile water and bacteriostatic water
Molecular Weight (MS)2899.40 Da — Confirmed
Endotoxin (LAL)<0.1 EU/mg
Sterility (USP <71>)Passes USP <71>

This COA is a representative sample. A batch-specific Certificate of Analysis with full HPLC chromatograms and mass spectrometry data is included with every MiPeptidos order.

Reconstitution Calculator

Add this much bacteriostatic water:
5.0 mL
5 mg Orexin B + 5.0 mL BAC water = 1 mg/mL

Inject bacteriostatic water slowly along the vial wall. Gently swirl until dissolved — never shake. Store reconstituted solution at 2-8°C and use within 30 days.

Download Product Brochure

Get our detailed Orexin B product brochure with specifications, research applications, HPLC analysis data, and reconstitution guide. Available in English and Spanish.

Customer Reviews

5.0/5from 1 review
Verified
Dr. Samira Patel·London, UK

Orexin-B (hypocretin-2) from MiPeptidos shows the expected OX2R selectivity in our receptor binding studies, complementing our Orexin-A work. The 28-residue peptide is properly synthesized and the C-terminal amidation is...

Dec 3, 2025
View All Reviews →

Frequently Asked Questions

Orexin B (CAS: 205640-91-1) is a research compound, with a molecular weight of 2899.40 Da in the Cognitive / Neuropeptides category. Orexin B is a 28-amino acid neuropeptide co-expressed with Orexin A in lateral hypothalamic neurons. Unlike Orexin A (which binds both OX1R and OX2R equally), Orexin B preferentially binds OX2R with ~10-fold selectivity over OX1R. Researchers commonly investigate Orexin B for OX2R-selective orexin signaling, REM sleep regulation, Narcolepsy treatment research. Every vial from MiPeptidos includes batch-specific analytical documentation.
Orexin B is available in 2 sizes (5mg, 10mg), so reconstitution volume depends on which vial you have. For the 5mg size, add 1-2mL of bacteriostatic water; for the 10mg size, use 2-3mL. Always let the vial warm to room temperature first, inject the water slowly along the vial wall, and swirl gently — never shake. Store reconstituted Orexin B at 2-8°C and use within 30 days. MiPeptidos carries bacteriostatic water in 3mL and 10mL vials.
Orexin B (28 amino acids, 2899 Da) selectively binds OX2R receptors rather than activating both orexin receptor subtypes like Orexin A. This OX2R selectivity is significant because OX2R is the primary receptor mediating wakefulness and arousal — OX2R-knockout animals show narcolepsy phenotypes. Orexin B lacks the disulfide bonds present in Orexin A, giving it a shorter half-life but potentially cleaner receptor subtype selectivity. MiPeptidos carries both for orexin pathway research.
Store lyophilized Orexin B at -20°C for maximum long-term stability — properly stored, it remains potent for 24+ months. Once reconstituted with bacteriostatic water, keep it refrigerated at 2-8°C and use within 30 days. In research applications, Orexin B has a reported half-life of ~5-7 minutes in plasma (shorter than Orexin A due to lack of disulfide bonds), which informs dosing frequency and protocol design. Avoid repeated freeze-thaw cycles and protect from direct light. MiPeptidos ships every order with cold-chain packaging to maintain integrity during transit.
Every Orexin B order from MiPeptidos includes a batch-specific Certificate of Analysis. Our current batch (HR-RXNB-2600315, tested January 17, 2026) shows 99.1% purity by HPLC, mass spectrometry confirmation at 2899.40 Da, endotoxin levels below 0.1 EU/mg, and passing sterility per USP <71>. This level of documentation ensures you can verify compound identity and purity before beginning your research. MiPeptidos also offers bulk pricing on orders of 50+ vials — contact info@mipeptidos.com.

Specifications

Purity
≥99%
Form
Lyophilized Powder
CAS Number
205640-91-1
Mol. Weight
2899.40 Da
Formula
C123H212N44O35S
Half-Life
~5-7 minutes in plasma (shorter than Orexin A due to lack of disulfide bonds)
Storage
Store at -20°C. Reconstituted: 2–8°C for up to 30 days.
Sizes
5mg, 10mg

Sequence

RSGPPGLQGRLQRLLQASGNHAAGILTM-NH2 (28 amino acids, C-terminal amide, no disulfide bonds)

Research Use Only. This product is intended for laboratory research purposes only. Not for human consumption. Handle with appropriate safety precautions.

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