Orexin-A

also known as hypocretin-1

research compound hormone nervous sequence not characterised

247 heavy atoms · 497 bonds · drag to pan, scroll to zoom C152N47O44S4

Skeletal structure drawn from the computed atomic coordinates in PubChem CID 56842143. Carbons are implicit vertices; hydrogens on carbon are suppressed, as in any structural formula. Nothing here is estimated — every atom sits where PubChem placed it.

Research reference only. The observations below are recorded in the cited literature. Nothing here is advice or a recommendation, and no dosing information is published on this site.

Sequence

Primary structure not characterised in the public records this index draws on. Nothing is shown rather than something invented.

Pyroglutamate N-terminus, C-terminal amide, and two intrachain disulfide bonds.

Molecular data

Chemical fields come from the PubChem compound record; computed values are derived from the sequence shown above.
molecular formula	C152H243N47O44S4
molecular weight	3561.1 Da (PubChem)
computed backbone mass	not characterised
length	not characterised
net charge (pH 7.4)	not characterised
mean hydropathy	not characterised
half-life	not characterised
delivery route	not characterised
PubChem CID	56842143
PDB	not characterised
UniProt parent	O43612

Mechanism

OX1R/OX2R agonist; central regulator of arousal and wakefulness.

Reported targets: OX1R OX2R

Experimental structure

No experimental structure of this peptide is deposited in the PDB. Nothing is rendered here — a predicted fold would not be a structure, and this site does not draw one.

Parent protein

Orexin-A and orexin-B share a precursor. UniProt O43612 · 131 aa

Reported effects

Each row is an outcome described in the literature indexed for this peptide. Reported in the cited work — not a claim, not a recommendation.

Reported observations and the corpus they are drawn from.
reported outcome	where it appears
wakefulness in models	Identification and quantification of Hypocretin-1/Orexin-A 1-14 and 1-16 fra… Sleep medicine 2026
appetite effects in models	16-mer hypocretin-1/orexin-A in cerebrospinal fluid to diagnose narcolepsy Sleep 2025

Registered trials

Records from ClinicalTrials.gov. Listed for reference — this project sponsors no trial and is not involved in any of them.
NCT	title	status	phase
NCT05446025	The Levels of the Orexin, Galanin and aMSH and CART in Patients With Hyperemesis Gravidarum	COMPLETED	—
NCT03947281	Snacks and Satiety	TERMINATED	NA
NCT01638403	Effects of BF2.649 in the Treatment of Excessive Daytime Sleepiness in Narcolepsy.	COMPLETED	PHASE3
NCT03025295	The Effect of Orexin on Delayed Emergence of General Anesthesia in Dexmedetomidine	COMPLETED	NA
NCT05795270	Multicenter Study on the Role of Neurodegeneration Biomarkers in Obstructive Sleep Apnea Syn	UNKNOWN	—

Literature (7)

Identification and quantification of Hypocretin-1/Orexin-A 1-14 and 1-16 fragments in immunopurified cerebrospinal fluid using LC-MS: Comparison with radioimmunoassay (RIA) determinations — Sleep medicine 2026