Orexin A
Aliases: Hypocretin-1
Last verified: 2026-09-24
The short version
Orexin A is administratively interesting: its system is one of the most important discovered in sleep neurobiology, and its activation treats narcolepsy — except that small molecules do the treating. Peptide orexin A suffers from a fateful problem: 33 amino acids, rapid degradation, unreliable intranasal transfer, short action. The community sells it as a 'wakefulness peptide', but the effect they seek (clean, predictable wakefulness) is precisely what the peptide form cannot deliver and molecular agonists can. This is an example of a substance scientifically interesting and practically obsolete before it became available.
Identity & type
- Molecular type
- neuropeptide
- Molecular weight
- ~3.6 kDa
- Origin
- The natural human neuropeptide; the gray version is a synthetic analog of the same sequence.
Mechanism of action
A 33-amino-acid neuropeptide from the lateral hypothalamus; agonist of orexin receptors OX1R/OX2R that governs wakefulness, appetite and REM control; deficient orexin signaling is the cause of narcolepsy — orexin agonists are the hottest direction for treating that disease.
not confirmed in humans
Dosing & routes
Official / clinical context
No official context for the peptide; molecular orexin agonists have their own development framework.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
Intranasal in the morning ('wakefulness without caffeine'), 100–300 µg; reports are variable — from 'works like modafinil' to 'nothing', consistent with unreliable intranasal bioavailability.
Unverified self-reports. Not medical advice. Not endorsement.
Protocol — official vs community
Official / label
No approved protocol exists — preclinical/pilot-stage agent. Small human pilot work used intranasal µg doses; the orexin agonists actually advancing in clinical development (e.g. TAK-861) are small molecules, not peptides.
Duration: —
The peptide's pharmacology is compelling — orexin deficiency is the cause of narcolepsy — but peptides generally don't deliver the CNS exposure the indication requires, which is why the field moved to non-peptide agonists.
Community (anecdotal)
Structured protocol data for this entry is coming.
Human evidence
Minimal: a couple of small pilot studies of intranasal orexin A without clear outcomes; no controlled studies with published positive results.
Preclinical evidence
Fundamentally rich (orexin biology is key), but intervention data with the peptide are limited to pokes and small pilots.
Known risks
- Excessive wakefulness and sleep disturbance with late dosingtheoretical
- Anxiety and cardiovascular effects (theoretical)theoretical
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- Bioavailability of intranasal administration in humans
- Effect and safety with repeated use
Frequently asked questions
References
- Intranasal orexin A pilot studies in sleep disorders (small human series)
- TAK-861/danavorexton phase 2 in narcolepsy — the molecular direction