Metabolic & Weight Management

Orexin-B

Orexin-B is one of the two hypothalamic orexin peptides that hold the brain in a stable waking state. It is selective for the OX2 receptor, the subtype most implicated in sleep-wake control, which makes it a precise tool for working out which orexin receptor carries which job, and it appears in feeding research alongside that. The strangest entry on its record sits elsewhere entirely: its single human citation is a case-control comparison of blood levels in 38 patients with brain aneurysms against 43 controls, from a paper proposing an effect on the vessel wall. No person has been given orexin-B as a drug, and the record establishes no human dose.

Last updated 12 August 2026

Studied forSleep-wake research · Feeding behaviour research · OX2 receptor pharmacology

Evidence on file3 animal studies

Strongest sourceOrexin B Reduces Cerebral Aneurysms Through Inhibition of SP-1. (animal study)

Mechanism

Selective for the OX2 receptor, the subtype most implicated in sleep-wake stabilisation, with much weaker OX1 receptor activity.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

Sleep-wake research
Feeding behaviour research
OX2 receptor pharmacology

Dosing on file unverified

No established human dose

Carried from a source that labels it unverified, and reproduced with that label attached. A record of what is reported, not a recommendation. No citation on this page establishes it.

Literature on file 5

review or editorial
Neuroendocrine Control of the Testis: Focus on Orexinergic Modulation of Spermatogenesis. graded on: indexed as "Review" - secondary literature, not a study — “Review”
review or editorial
Lateral hypothalamic orexinergic neurons as central mediators of pain modulation and non-pharmacological analgesia. graded on: indexed as "Review" - secondary literature, not a study — “Review”
animal in vivo
Orexin B Reduces Cerebral Aneurysms Through Inhibition of SP-1. graded on: an animal model — read from the indexed abstract — “mice”
animal in vivo
Sexually dimorphic mediation of experimental post-traumatic headache by orexin receptor signaling. graded on: an animal model — read from the indexed abstract — “mice”
animal in vivo
Modulation of electrically evoked hippocampal epileptiform activity by exogenous orexins in the rat CA1 field. graded on: an animal model — “rat”

Identity

Space-filling 3D model of Orexin-B, carbon grey, nitrogen blue, oxygen red — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

2D chemical structure of Orexin-B — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

Molecular weight: 2899.3
Molecular formula: C123H212N44O35S
CAS number: 205599-76-4
PubChem CID: 44404987
InChI key: OHOWSYIKESXDMN-WMQZXSDYSA-N
SMILES: CC[C@H](C)[C@@H](C(=O)NCC(=O)N[C@@H](C)C(=O)N[C@@H](C)C(=O)N[C@@H](CC1=CNC=N1)C(=O)N[C@@H](CC(=O)N)C(=O)NCC(=O)N[C@@H](CO)C(=O)N[C@@H](C)C(=O)N[C@@H](CCC(=O)N)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCN=C(N)N)C(=O)N[C@@H](CCC(=O)N)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCN=C(N)N)C(=O)NCC(=O)N[C@@H](CCC(=O)N)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N2CCC[C@H]2C(=O)N3CCC[C@H]3C(=O)NCC(=O)N[C@@H](CO)C(=O)N[C@@H](CCCN=C(N)N)C(=O)N)NC(=O)[C@H](CC(C)C)NC(=O)[C@H]([C@@H](C)O)NC(=O)[C@H](CCSC)N
InChI: InChI=1S/C123H212N44O35S/c1-18-63(12)96(164-114(196)80(46-62(10)11)163-119(201)97(67(16)170)165-102(184)69(124)35-41-203-17)118(200)143-50-91(175)146-64(13)99(181)147-65(14)101(183)157-81(47-68-49-136-57-145-68)113(195)162-82(48-90(128)174)105(187)141-52-93(177)150-83(55-168)115(197)148-66(15)100(182)153-74(30-33-88(126)172)108(190)160-79(45-61(8)9)112(194)161-78(44-60(6)7)111(193)155-72(26-21-38-139-123(134)135)106(188)156-75(31-34-89(127)173)109(191)159-77(43-59(4)5)110(192)154-71(25-20-37-138-122(132)133)103(185)140-51-92(176)149-73(29-32-87(125)171)107(189)158-76(42-58(2)3)104(186)144-54-95(179)166-39-23-28-86(166)120(202)167-40-22-27-85(167)117(199)142-53-94(178)151-84(56-169)116(198)152-70(98(129)180)24-19-36-137-121(130)131/h49,57-67,69-86,96-97,168-170H,18-48,50-56,124H2,1-17H3,(H2,125,171)(H2,126,172)(H2,127,173)(H2,128,174)(H2,129,180)(H,136,145)(H,140,185)(H,141,187)(H,142,199)(H,143,200)(H,144,186)(H,146,175)(H,147,181)(H,148,197)(H,149,176)(H,150,177)(H,151,178)(H,152,198)(H,153,182)(H,154,192)(H,155,193)(H,156,188)(H,157,183)(H,158,189)(H,159,191)(H,160,190)(H,161,194)(H,162,195)(H,163,201)(H,164,196)(H,165,184)(H4,130,131,137)(H4,132,133,138)(H4,134,135,139)/t63-,64-,65-,66-,67+,69-,70-,71-,72-,73-,74-,75-,76-,77-,78-,79-,80-,81-,82-,83-,84-,85-,86-,96-,97-/m0/s1

Notes unverified prose

No human dosing studies identified; research only; No human dosing trials; biomarker studies only

Not on file 3

1 of the 8 fields we track hold nothing on this record, and each says why. 2 further absences are named below. A blank field is a bug; a named absence is a finding.

amino-acid sequencenothing we hold supplies it
half-lifenothing we hold supplies it
route of administrationnothing we hold supplies it

Each field links to every other record missing the same thing. The full ledger holds 765 gaps across 163 records.

Listed prices 4

What 2 shops we track listed for Orexin-B, read from their own public catalogues on 2026-09-14. We take no commission on these and they are not ranked by any payment — how vendors are scored.

Compare prices4 listings from 2 shops

Listed in USD
Vendor	Size	Price	Per mg
Behemoth Labz	5 mg	$261.96 USD	$52.39/mg
PureRawz ships worldwide	5 mg	$262.08 USD	$52.42/mg
Behemoth Labz	1 mg	$159.47 USD	$159.47/mg
PureRawz ships worldwide	1 mg	$159.61 USD	$159.61/mg

Prices are the vendor's own listing, reproduced with the date we read it — never converted between currencies, and compared per milligram only where the vendor states the vial size.