Orexin-A

Orexin-A (Hypocretin-1)

Evidence & Status

  • Preliminary / Experimental
  • Preliminary

At a Glance

An endogenous hypothalamic neuropeptide that is the brain's principal wakefulness-promoting signal. The selective destruction of orexin-producing neurons is the direct biological cause of narcolepsy type 1, making it central to sleep medicine and circadian research.

Plain English

Researchers study Orexin-A because it is part of the brain's wakefulness system. Human intranasal studies are small and experimental, so they do not establish an Orexin-A treatment or a routine dose. Drugs that block orexin receptors are separate medicines and do not provide direct evidence for giving Orexin-A itself.

Overview

Orexin-A (Hypocretin-1) is a 33-amino-acid hypothalamic neuropeptide and one of two orexin peptides, the other being Orexin-B. Orexin-A signals through OX1R and OX2R and participates in wakefulness, arousal, energy homeostasis, reward, and autonomic regulation. Direct human intranasal Orexin-A research exists, but the studies are small and experimental and do not establish routine treatment or general therapeutic efficacy. Orexin receptor antagonist drugs are separate entities and their approvals do not demonstrate efficacy or safety for exogenous Orexin-A.

Research Summary

Orexin-A is a wakefulness-promoting hypothalamic neuropeptide with extensive pathway and preclinical research. Direct human evidence for exogenous Orexin-A consists of small experimental intranasal studies in narcolepsy and a study of autonomic/vascular effects. These studies do not establish Orexin-A as a routine treatment, and any administered amount is study-specific exposure. Approved orexin receptor antagonists act differently and provide pathway context only; they are not evidence for exogenous Orexin-A efficacy or safety.

Research Areas

  • Narcolepsy
  • Wakefulness
  • Sleep disorders
  • Cognitive performance
  • Reward and addiction
  • Energy homeostasis

Safety & Risks

Serious Risks

  • Unknown in humans; theoretical cardiovascular stimulation; addiction/reward pathway activation (orexin system regulates reward); off-label self-administration not advisable

Reported Side Effects

  • Not well characterized in humans; animal studies: increased arousal, elevated body temperature, reduced food intake at high doses
United States
Research only; Orexin-A is not approved for human therapeutic use.
United Kingdom
Research only; Orexin-A is not approved for human therapeutic use.
Australia
Research only; Orexin-A is not approved for human therapeutic use.
Canada
Research only; Orexin-A is not approved for human therapeutic use.

Citations & Sources