Neuro & cognitive
Orexin B
A distinct endogenous 28-amino-acid orexin peptide studied mainly in receptor, tissue and animal experiments; no verified human intervention was identified.
- How settled this rating is:
- low confidence in the current evidence rating
- Routes studied:
- Not established
- Also known as:
- Hypocretin-2, hcrt-2, orexin-B peptide
- Last reviewed:
- 2026-09-26
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Evidence passport
Orexin B
A one-screen evidence identity for this compound. These fields describe research maturity, confidence and legal status. They are not a safety guarantee, efficacy percentage or recommendation.
- Evidence level
- L1Theory only
- Confidence
- Low confidence in rating
- Regulatory status
- Not approved for this use
- Development status
- Preclinical
Evidence strength
Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.
The 0-100 values rate the strength and maturity of evidence, not how effective or safe the compound is.
- Evidence base
- Mostly animal and laboratory research
- Furthest established stage
- Not established
- Human research maturity
- Preclinical (receptor, tissue and animal studies)
- Source curation
- Sources fully curated
Routes recorded
Most of this evidence comes from animals and cells
Overview
Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.
How to read these scores
Every number here rates the evidence, not the compound. They are editorial 0-100 strength ratings, not percentages, and not a rating out of five stars.
- Human efficacy evidence strength — Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
- Preclinical evidence strength — Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
- Human safety evidence strength — Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number. A score of 80 does not mean “80% safe”.
- Evidence level (L0-L5) — the strongest type of study behind the compound, from anecdote (L0) to large replicated human trials (L5). It is a description of the study evidence, not a quality, safety or recommendation rating.
- Confidence — how likely we think it is that this rating changes as new research lands. Low confidence means the picture is unsettled, not that the compound is bad.
None of these ratings is medical advice, a safety guarantee, or a recommendation to use anything. How we grade evidence.
How far human research has progressed: Preclinical (receptor, tissue and animal studies)
Routes & formulations
Central administration in rats is preclinical procedure evidence, not an established human route. No verified human administration study was identified.
Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.
Peptide lifecycle
Discovery
Preclinical
Phase I
Phase II
Phase III
Approved
What it is
An endogenous 28-amino-acid neuropeptide, also called hypocretin-2, produced from the same precursor as Orexin A. It is a distinct peptide with a different receptor-affinity profile. Orexin A trials, orexin receptor medicines and engineered analogues are separate evidence streams.
What people claim
- Wakefulness and focus
- Appetite or metabolism effects
- Narcolepsy treatment
What the evidence actually says
Primary studies establish Orexin B as a native orexin-system ligand and describe receptor activity, rat central-administration effects and responses in excised human adipose tissue. Tissue from people is not a human intervention. No verified human efficacy, safety or administration study of native Orexin B was identified.
Related evidence
Useful next reads based on this compound — not recommendations.
- Related compound
Brenipatide evidence profile
An investigational dual GIP and GLP-1 receptor agonist now in Phase 3 trials for alcohol use disorder and major depressive disorder, with no efficacy results published.
- Compare
Compare Orexin B vs Brenipatide evidence
Same questions, same fields, side by side — including how much human evidence exists.
- Context
Research Desk
How to read animal, early-phase and controlled human studies without over-reading them.
- Context
Safety Centre
What approved, investigational and unapproved actually mean for documented human safety.
Human evidence
- Excised human adipose tissue and isolated adipocytes responded in laboratory assays (PMID 17065396); no person was dosed.
- No verified human interventional efficacy, safety or pharmacokinetic study of native Orexin B was identified.
Preclinical evidence
- Centrally administered Orexin B and Orexin A were compared in rats (PMID 11205421); this does not establish a human route.
- In-vitro receptor studies compared native peptides and truncated analogues (PMID 14971895); analogue findings cannot be assigned to native Orexin B.
- Photorexin is an engineered Orexin-B analogue tested in vitro and in zebrafish larvae (PMID 38970689), not native Orexin B evidence.
Animal and cell findings are Level 1–2 evidence.
Mechanism and pathways
- Agonist at OX1R and OX2R, with comparatively greater affinity for OX2R than OX1R.
- Orexin-system physiology is well established, but that does not establish a therapeutic effect for administered native Orexin B.
Safety and unknowns
- No human administration or safety dataset was identified.
- Material sold online is unregulated: identity, purity, sterility and labelled quantity are separate questions from what the published molecule does.
Cancer relevance
This section covers questions raised by how the compound works in the body, plus anything regulators and trial teams keep an eye on. It is not a statement that this compound causes cancer — for most compounds here, no human data exist in either direction.
No established human signal
Regulatory status
Regulatory decisions apply to specific jurisdictions, products, formulations and indications. An approval elsewhere is not automatically an approval in your country.
Check the regulatory note and linked primary sources for jurisdiction-specific details.
Orexin B itself is not an approved medicine. Evidence for Orexin A, engineered orexin analogues or small-molecule orexin receptor drugs must not be transferred to this peptide.
Evidence grade
Mechanistic rationale or early development without qualifying compound-specific outcome evidence. A registered trial is not a result.
What would change our rating?
- A registered first-in-human study of chemically verified native Orexin B with pharmacokinetics and safety reporting.
- Independent translational studies that do not rely on Orexin A, receptor drugs or engineered analogues.
References and sources
Source transparency
A provenance snapshot of this profile. Counts show what kinds of sources are cited, not how much scientific weight each source deserves.
- Last editorial review
- 2026-09-26
- Recently reviewed · 20 days ago
- Linked curated sources
- 6
- Sources still pending
- 0
- External specialist reviews
- 0
- None recorded for this profile
Review provenance
Registry editorial review: Colin Jackson-White, creator and editor, who is not a doctor or clinician. External specialist review is credited only when a named reviewer has completed a review of this exact profile.
Literature-discovery and AI tools may help locate or challenge candidate evidence, but they are not counted as evidence sources here. Registry judgements are tied to the underlying papers, trial records, regulator documents and official study records.
- Peer-reviewedde Lecea et al. The hypocretins: hypothalamus-specific peptides with neuroexcitatory activity. PNAS 1998 (PMID 9491897)PMID: 9491897
- Peer-reviewedEffects of centrally administered orexin-B and orexin-A in rats. 2001 (PMID 11205421)PMID: 11205421
- Peer-reviewedOrexin receptor structure–activity study of peptides and analogues. 2004 (PMID 14971895)PMID: 14971895
- Peer-reviewedOrexin receptors and responses in human adipose tissue and isolated adipocytes. 2006 (PMID 17065396)PMID: 17065396
- Peer-reviewedOrexin receptor pharmacology and therapeutic opportunities review. 2011 (PMID 21034217)PMID: 21034217
- Peer-reviewedPhotorexin, an engineered Orexin-B analogue tested in zebrafish — not native Orexin B. 2024 (PMID 38970689)PMID: 38970689
Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.
Evidence change history
These entries record changes to our assessment of the published evidence — not changes to the compound itself.
No recorded changes yet. Baseline position set on 2026-09-26.