Orexin B
The second orexin (hypocretin) peptide, working alongside orexin A to sustain wakefulness.
Not approved. Research use only.
Look it up on Wikipedia4 listings across 1 independently tested vendor, ranked by price per milligram after coupon codes anyone can use. Vendors you can only order from by message are hidden.
Not an FDA-approved drug and not nominated for FDA's 503A bulks list, so US pharmacies can't legally compound it.
Daily price tracking started October 7, 2026; a price-history chart appears here once a few days have been collected.
| Vendor | Trust | Listing | Vials | Price | Per mg | |
|---|---|---|---|---|---|---|
Qingdao Sigma Chemical QSC #69 by metascore |
Orexin B 10mg | 20-Vial Kit | Hypocretin-2 High-Dose | OX2R Research | 20 × 10 mg = 200 mg | $650.00 $32.50 per vial |
$3.25 | Buy | |
Qingdao Sigma Chemical QSC #69 by metascore |
Orexin B 10mg | 10-Vial Kit | Hypocretin-2 High-Dose | OX2R Research | 10 × 10 mg = 100 mg | $350.00 $35.00 per vial |
$3.50 | Buy | |
Qingdao Sigma Chemical QSC #69 by metascore |
Orexin B 5mg | 20-Vial Kit | Hypocretin-2 | OX2R Selective Sleep & Arousal Research | 20 × 5 mg = 100 mg | $490.00 $24.50 per vial |
$4.90 | Buy | |
Qingdao Sigma Chemical QSC #69 by metascore |
Orexin B 5mg | 10-Vial Kit | Hypocretin-2 | OX2R Selective Sleep & Arousal Research | 10 × 5 mg = 50 mg | $270.00 $27.00 per vial |
$5.40 | Buy |
Mixing a 5 mg vial
What each common amount of bacteriostatic water gives you on a U-100 insulin syringe. Pick a vial size above to change it.
| Water | Strength | Per 10 units (0.1 mL) | Per unit |
|---|---|---|---|
| 1 mL | 5 mg/mL | 500 mcg | 50 mcg |
| 2 mL | 2.5 mg/mL | 250 mcg | 25 mcg |
| 3 mL | 1.667 mg/mL | 166.7 mcg | 16.67 mcg |
| 5 mL | 1 mg/mL | 100 mcg | 10 mcg |
Doses studied in research Animal or lab studies only
What was given to people (or animals) in published studies and official labels, each linked to its source. This is not a recommendation: study products, purity and supervision differ from research-grade vials.
Animal studies: Animal studies used, for example, 30 micrograms/kg/day for 7 weeks in mice (aneurysm model, PMID 42257697), a single 3 mg/kg intramuscular injection in young pigs (PMID 10343916), and direct brain (intracerebroventricular) injection in parkinsonian mice (PMID 34666119).
No studies giving orexin B to people were found. Doses in animal studies do not translate directly to people. Not an approved drug.
What the research says
Evidence for administered orexin B is limited to animal and cell studies (Parkinson's models, neuropathic pain, sepsis, aneurysm, cardiac protection, retina, adipose cells), and one rat study found no effect on epileptiform activity; no human administration studies were found. The only human data measure the body's own orexin B levels, for example higher plasma levels in depression.
Key papers ✓ 8✗ 1? 2
-
The roles of orexins in sleep/wake regulation.No new dataNarrative review
Review of orexin A and B in sleep/wake regulation: orexin signalling deficiency causes narcolepsy; does not evaluate orexin B as a treatment.
Study details
- Studied
- Literature on orexin neuropeptides and sleep/wake regulation
- Authors' conclusion
- Orexins play critical roles in maintaining wakefulness by regulating monoaminergic and cholinergic neurons, and deficient orexin signaling causes narcolepsy-cataplexy.
- Limitations
- Review of orexins generally (A and B), not orexin-B specifically; no original data.
-
Orexin-B exerts excitatory effects on nigral dopaminergic neurons and alleviates motor disorders in MPTP parkinsonian mice.Animalssize not reportedElectrophysiology on nigral dopaminergic neurons plus intracerebroventricular orexin-B
In MPTP parkinsonian mice, intracerebroventricular orexin B reduced dopaminergic neuron degeneration and improved motor coordination.
Study details
- Studied
- MPTP parkinsonian mice
- Compared with
- Orexin-2 receptor blockade
- Main outcome
- Dopaminergic neuron firing, degeneration, spontaneous activity and motor coordination
- Authors' conclusion
- Orexin-B may protect dopaminergic neurons and improve motor disorders in parkinsonian mice, partly via excitatory effects on nigral dopaminergic neurons through orexin-2 receptor.
- Limitations
- Mouse model only.
-
Orexin B protects dopaminergic neurons from 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity associated with reduced extracellular signal-regulated kinase phosphorylation.Humans + animals24 h after MPP+ challenge in cellsIn vivo mouse model and in vitro cell model with RNA-Seq and Western blot
Orexin B reduced MPTP-induced dopaminergic neuron loss and improved motor ability in mice, and reduced MPP+ toxicity in SH-SY5Y cells.
Study details
- Studied
- MPTP-treated mice and MPP+-treated SH-SY5Y cells (Parkinson's models)
- Main outcome
- Dopaminergic neuron death, pole test motor function, ERK phosphorylation
- Authors' conclusion
- Orexin B decreased dopaminergic neuron death, alleviated neurotoxicity and enhanced motor ability, associated with reduced ERK phosphorylation; it may have therapeutic potential for Parkinson's disease.
- Limitations
- Mouse and cell models only.
-
The protective effects of orexin B in neuropathic pain by suppressing inflammatory response.Animalssize not reportedDose-dependent orexin B administration with behavioral and molecular assays
In rats with chronic constriction nerve injury, orexin B dose-dependently reduced neuropathic pain behaviour and spinal inflammation.
Study details
- Studied
- Rats with chronic constriction injury-induced neuropathic pain
- Compared with
- CCI-treated rats without orexin B
- Main outcome
- Mechanical withdrawal threshold, thermal withdrawal latency, spinal inflammatory markers
- Authors' conclusion
- Orexin B might ameliorate CCI-evoked neuropathic pain by inhibiting microglial activation and inflammatory response, via JNK/NF-kB signaling.
- Limitations
- Rat model only.
-
Orexin B Reduces Cerebral Aneurysms Through Inhibition of SP-1.Humans + animalsOrexin B 30 μg/kg/day for 7 weeksSerum measurement, murine aneurysm model, in vitro studies
In an elastase-induced mouse aneurysm model, orexin B roughly halved aneurysm size (3.72 to 1.93 mm) via OX2R; patients with aneurysms had lower serum orexin B.
Key resultSerum Orexin B was 3.21 ± 0.52 in patients vs 8.56 ± 1.23 pg/mL in controls (p < 0.01); orexin B reduced aneurysm size in WT mice from 3.72 ± 0.469 mm to 1.93 ± 0.252 mm (p < 0.01) but not in OX2R-/- mice
Study details
- Studied
- Patients with cerebral aneurysms and controls; elastase-induced aneurysm in WT and OX2R knockout mice; human brain microvascular endothelial cells
- Compared with
- Untreated mice and OX2R-/- mice
- Main outcome
- Aneurysm size, inflammatory mediators, SP-1 expression
- Sample
- 38 aneurysm patients and 43 healthy controls (serum levels); mice and cells for the main experiments
- Authors' conclusion
- Orexin B protects against cerebral aneurysm formation through OX2R-dependent anti-inflammatory mechanisms involving SP-1 suppression, a potential therapeutic target.
- Limitations
- Patient data are serum levels only; treatment effects shown in mice and cells.
-
orexin B alleviates sepsis-associated lung injury through the attenuation of pulmonary endothelial barrier dysfunction by regulating the rho-associated coiled-coil containing protein kinase 2/zonula occludens-1 (ROCK2/ZO-1) axis.Humans + animalsSham/vehicle controlFour-group animal experiment (Sham, Sham+orexin B, CLP, CLP+orexin B) plus in vitro model
In septic mice, orexin B decreased mortality and lung injury and reduced pulmonary inflammatory markers.
Study details
- Studied
- Mice with cecal ligation and puncture sepsis and LPS-treated mouse lung microvascular endothelial cells
- Compared with
- CLP without orexin B
- Main outcome
- Mortality, M-CASS score, lung injury, endothelial permeability
- Authors' conclusion
- Orexin B alleviates sepsis-induced acute lung injury by ameliorating lung endothelial permeability, via ROCK2 and ZO-1/occludin.
- Limitations
- Mouse and cell models only.
-
Functional cardiac orexin receptors: role of orexin-B/orexin 2 receptor in myocardial protection.Humans + animalsExpression analysis, isolated cardiomyocyte, Langendorff ischaemia/reperfusion and in vivo rat models
In rat heart models, orexin B (not orexin A) increased cardiomyocyte contraction and was cardioprotective after ischaemia/reperfusion.
Study details
- Studied
- Rat hearts and isolated cardiomyocytes, and human heart samples including heart failure patients
- Compared with
- Orexin-A
- Main outcome
- Contractile shortening, protein phosphorylation, ischaemia/reperfusion protection
- Authors' conclusion
- The authors provide evidence of a distinct orexin system in the heart that exerts a cardioprotective role via an orexin-B/OX2R pathway; OX2R expression correlated negatively with heart failure severity.
- Limitations
- Mostly rat models.
-
Cloning of porcine prepro-orexin cDNA and effects of an intramuscular injection of synthetic porcine orexin-B on feed intake in young pigs.Animalssize not reportedSham/vehicle controlFeed intake monitored 24 hIntramuscular orexin-B vs vehicle injection
In weanling pigs, a single intramuscular injection of orexin B led to an extra meal at 12 h compared with controls.
Key resultTotal feed intake at 24 h improved by 18% in orexin-treated pigs (P = 0.05); an additional meal at 12 h (P = 0.02)
Study details
- Studied
- Weanling piglets
- Compared with
- Vehicle (sterile water)
- Main outcome
- Feed intake
- Sample
- 26 cross-bred piglets in three replicates (written out in words)
- Authors' conclusion
- Orexin-B stimulated feed intake in young pigs; stimulating appetite after weaning could improve swine-production efficiency.
- Limitations
- Single dose, short 24 h observation in pigs.
-
Modulation of electrically evoked hippocampal epileptiform activity by exogenous orexins in the rat CA1 field.Animalssize not reportedIn vivo electrophysiology with intraventricular or cortical orexin-A or orexin-B
In anesthetized rats, orexin-B given into the ventricle or cortex (10 µg/10 µl) did not significantly change electrically evoked hippocampal epileptiform activity, whereas orexin-A reduced it.
Study details
- Studied
- Anesthetized rats with electrically evoked hippocampal CA1 epileptiform discharges
- Compared with
- Control animals; orexin-A
- Main outcome
- Duration and amplitude of epileptiform discharges
- Authors' conclusion
- Neither cortical nor intraventricular orexin-B significantly changed evoked epileptiform activity, suggesting the orexin-A effect may involve OX1 receptor signalling.
- Limitations
- Acute anesthetized rat experiment; group sizes not given in the abstract.
-
Orexin-B modulates synaptic transmission of rod bipolar cells in rat retina.Animalssize not reportedElectroretinography and patch-clamp recordings with orexin-B and receptor/pathway blockers
In rats, intravitreal orexin-B increased the amplitude of the electroretinographic b-wave and, in retinal slices, suppressed GABA-receptor currents of rod bipolar cells through OX1R and OX2R.
Study details
- Studied
- Rat retina in vivo and in slices or isolated rod bipolar cells
- Main outcome
- Rod bipolar cell activity and GABA receptor-mediated currents
- Authors' conclusion
- Orexin-B potentiated rod bipolar cell activity, which the authors suggest may improve visual acuity and contrast sensitivity in the dark phase.
- Limitations
- Basic physiology in rat tissue; the visual benefit is speculative.
-
Orexin B inhibits viability and differentiation of stromal cells from swine adipose tissue.Cells / labIn vitro orexin B treatment
Orexin B reduced proliferation and adipogenic differentiation (P < 0.05) of cultured stromal cells from swine adipose tissue.
Key resultOrexin B inhibited ASC proliferation (P < 0.05) and adipogenic differentiation (P < 0.05)
Study details
- Studied
- Cultured adipose-derived stromal cells from pigs
- Compared with
- Untreated cells
- Main outcome
- Cell proliferation and adipogenic differentiation
- Authors' conclusion
- Orexin B modifies differentiation of swine adipose stromal cells, which may be of interest for lean-meat production and obesity research.
- Limitations
- Pig cell culture only; obesity relevance is extrapolated.
Reported side effects
No human safety data in the published literature.
✓ positive · ✗ negative · ~ mixed · ? inconclusive, judged on each paper's own main outcome. Grades: A strong human evidence → D little or none. Papers and verdicts are drawn from PubMed, Europe PMC and Russian journals (CyberLeninka); not medical advice.
Discussions elsewhere
Experiences and questions about Orexin B on other sites. Treat anecdotes with care.
Also sold in blends with Orexin B
Orexin A + Orexin B (1). The order planner uses these automatically when a blend is cheaper than separate vials.
Orexin B: questions people ask
What is Orexin B?
Wakefulness neuropeptide. The second orexin (hypocretin) peptide, working alongside orexin A to sustain wakefulness.
How much does Orexin B cost?
The cheapest Orexin B from an independently tested vendor is $3.25 per mg (Qingdao Sigma Chemical QSC, Orexin B 10mg | 20-Vial Kit | Hypocretin-2 High-Dose | OX2R Research, $650.00). Across 4 listings from 1 vendors the median is $4.90 per mg.
Where can I buy Orexin B?
1 vendors tested by Finnrick sell Orexin B. The cheapest per mg right now: Qingdao Sigma Chemical QSC ($3.25). 0 of them publish a lab report (COA) for Orexin B; compare lab scores and reports in the table above before buying.
Is Orexin B FDA approved?
Not approved. Research use only.
Can Orexin B be compounded in the US?
Not an FDA-approved drug and not nominated for FDA's 503A bulks list, so US pharmacies can't legally compound it. Compounding status for every peptide.
Does Orexin B work? What does the research say?
Evidence grade C (mostly animal studies), from 11 papers: No human administration studies; evidence comes from rodent and pig studies (Parkinson's, pain, sepsis, heart) and cell work. Evidence for administered orexin B is limited to animal and cell studies (Parkinson's models, neuropathic pain, sepsis, aneurysm, cardiac protection, retina, adipose cells), and one rat study found no effect on epileptiform activity; no human administration studies were found. The only human data measure the body's own orexin B levels, for example higher plasma levels in depression. See the papers.
What dose of Orexin B was used in studies?
Orexin B is tested only in animals or cells. Animal studies used, for example, 30 micrograms/kg/day for 7 weeks in mice (aneurysm model, PMID 42257697), a single 3 mg/kg intramuscular injection in young pigs (PMID 10343916), and direct brain (intracerebroventricular) injection in parkinsonian mice (PMID 34666119). These are amounts used in published studies or official labels, not a recommendation.