Orexin B
Also known as: Orexin B, Hypocretin-2
A 28-amino-acid hypothalamic neuropeptide that, alongside Orexin A, regulates arousal, wakefulness and feeding. It shows relative selectivity for the OX2R receptor subtype.
Last updated
Mechanism of Action
Orexin B (hypocretin-2) is cleaved from the same prepro-orexin precursor as Orexin A and signals through orexin receptors, with a marked preference for OX2R over OX1R. Activation of OX2R on histaminergic and monoaminergic neurons promotes cortical arousal and stabilizes the waking state. The peptide also contributes to appetite regulation and autonomic activation. Its OX2R selectivity makes it a useful probe for dissecting the wake-promoting versus reward-related roles of the orexin system.
- Half-life
- Short; on the order of minutes in circulation
- Administration Routes
- intranasal, subcutaneous
- Research Status
- Research Chemical
Reported Benefits
- Promotes wakefulness through OX2R signaling
- Studied for arousal and alertness
- Useful research probe for OX2R-specific effects
- Modulates feeding and energy balance
- Investigated in sleep-wake regulation research
Potential Side Effects
- Sleep disruption if used late in the day
- Elevated heart rate and blood pressure
- Restlessness or agitation
- Appetite changes
Common Dosing
Orexin B has been used almost exclusively in laboratory and animal research at microgram-scale amounts; no standardized human research dosing exists. Provided for research-use-only context and not as personal medical advice.
The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.
Contraindications
- Cardiovascular disease
- Sleep disorders such as insomnia
- Pregnancy and breastfeeding due to absence of safety data
- View
Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior
1998
- View
Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior
1998
- View
Orexin A but not orexin B rapidly enters brain from blood by simple diffusion
1999
- View
The wake-promoting peptide orexin-B inhibits glutamatergic transmission to dorsal raphe nucleus serotonin neurons through retrograde endocannabinoid signaling
2005
- View
Development of an orexin-2 receptor selective agonist, [Ala(11), D-Leu(15)]orexin-B
2003