Sleep

Orexin A Руководство и таблица дозировок

A hypothalamic neuropeptide that regulates wakefulness, arousal and appetite; central to narcolepsy research.

Также известен какHypocretin-1
Способ введенияsubcutaneous
Orexin A — Таблица дозировок
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Только для исследовательских и образовательных целей. Не является медицинской рекомендацией.
How to Reconstitute Orexin A
U-100

A common approach: reconstitute an example 5 mg vial of Orexin A with bacteriostatic water. The table shows the concentration at three common water volumes — use the calculator on this page for your specific target dose.

BAC waterConcentrationVolume / doseUnits (U-100)
1 mL5 mg/mL
2 mL2.5 mg/mL
3 mL1.67 mg/mL

Units shown are for a U-100 (1 mL = 100-unit) insulin syringe. Always verify your own math before drawing.

Orexin A Vial Sizes

Reconstitution worked out for each common vial size:

What is Orexin A?

Orexin A — also called Hypocretin-1 — is a small signaling protein (a neuropeptide) that the brain makes naturally. It is produced by a tight cluster of neurons deep in the hypothalamus, the brain region that acts like a master control panel for sleep, hunger, and body temperature. Despite being made by only a relatively small number of cells, Orexin A has an outsized influence: it reaches wide areas of the brain and helps keep you awake, alert, and emotionally stable.

Researchers first isolated orexin in 1998 and quickly realized it sat at the very center of how the brain switches between sleep and wakefulness. Today it is one of the most studied neuropeptides in sleep science, and it is classified as a research-use-only compound — meaning it is used in laboratory and preclinical studies, not as an approved treatment.

How Orexin A Works

Think of Orexin A as a "stay-awake" broadcast signal. When orexin neurons fire, they send Orexin A to receptors all over the brain — including regions that manage arousal, mood, and memory. Two receptors pick up this signal: Hypocretin Receptor 1 (HCRTR1) and Hypocretin Receptor 2 (HCRTR2).

When those receptors are activated, neurons that drive wakefulness stay active. When orexin neurons are lost or silenced, the brain loses the ability to reliably stay awake — the result is the sudden, uncontrollable sleep attacks seen in narcolepsy.[1]

Beyond sleep, HCRTR1 also appears to interact with brain circuits involved in memory and mood. Research in animal models suggests that abnormally high levels of Orexin A can interfere with how the hippocampus (the brain's memory hub) manages energy, potentially impairing cognitive function.[4] This hints that Orexin A is not just a simple on/off switch for sleep — it is a nuanced regulator of several brain systems.

What the Research Shows

Most of what scientists know about Orexin A comes from studying narcolepsy, a condition where the orexin-producing neurons are destroyed — almost certainly by an autoimmune process. Without those neurons, Orexin A levels in the cerebrospinal fluid (CSF — the fluid that bathes the brain and spinal cord) drop dramatically.[1]

That drop is now used as a diagnostic tool. A low CSF Orexin A level is considered a highly sensitive and specific biomarker for narcolepsy type 1, meaning the test rarely misses the disease and rarely flags someone who doesn't have it.[3] Current diagnosis relies on a technique called radioimmunoassay (RIA), but researchers are working to improve that. A 2025 study found that measuring a specific 16-amino-acid fragment of Orexin A by mass spectrometry achieved 98.1% sensitivity and 85.7% specificity for diagnosing narcolepsy type 1, with a strong correlation to the existing RIA standard.[2] This could make future diagnosis more precise and reproducible.

Scientists are also examining how accurately the standard RIA test detects Orexin A fragments versus the intact peptide, raising important questions about the validity of some research results that relied solely on RIA.[6]

On the mood and cognition front, a 2024 study found that elevated Orexin A — acting through HCRTR1 — reduced lactate production and lowered levels of BDNF (a key brain growth factor) in the hippocampus of depression model animals. This impaired memory and neuroplasticity, and blocking HCRTR1 reversed those effects.[4] The findings open a possible research avenue connecting orexin signaling to cognitive symptoms in depression.

Orexin A has also been linked to alcohol use. Animal research showed that binge-like alcohol exposure during adolescence led to persistently elevated Orexin A expression in the anterior hypothalamus in adulthood — a change that may contribute to long-lasting disruptions in sleep patterns.[5]

What Orexin A Is Being Studied For

  • Narcolepsy — understanding the biology of orexin neuron loss and developing biomarker tests[1][3]
  • Diagnostic tool development — improving CSF testing methods using mass spectrometry[2][6]
  • Depression and cognition — exploring how orexin-receptor interactions affect memory and brain plasticity[4]
  • Alcohol use disorders — mapping how early alcohol exposure alters the orexin system[5]
  • Orexin receptor agonist research — informing the development of non-peptide drugs that mimic Orexin A for potential therapeutic use[1][3]

How Orexin A Is Dosed in Research

Dosing protocols for Orexin A vary considerably across preclinical studies depending on the route of administration (e.g., intracerebroventricular injection, intranasal, or intravenous), the species being studied, and the research question being asked. Because no standardized human dosing exists — and because this is a research-only compound — there is no single universal protocol. Researchers should consult the dosage chart on this page for a structured reference of amounts reported in the scientific literature, and use the calculator to work out precise volumes once a peptide has been reconstituted. This page is for research reference only and does not constitute medical advice.

Mixing and Storing Orexin A

Orexin A is a peptide, which means it is fragile and needs careful handling. It typically arrives as a lyophilized (freeze-dried) powder. To reconstitute it, researchers generally add sterile water or a compatible aqueous buffer slowly down the side of the vial — never shake it, as this can break the peptide's structure. Once dissolved, aliquot (divide) the solution into small single-use portions and store them frozen at around −20 °C or colder to preserve stability. Avoid repeated freeze-thaw cycles, as each one can degrade the peptide. Reconstituted solutions should be kept on ice during experiments and used promptly. Always follow the specific storage guidance provided with the reagent and consult current literature for buffer recommendations relevant to your experimental model.

Sources

  1. Narcolepsy. — Journal of sleep research, 2022. PMID 35624073.
  2. 16-mer hypocretin-1/orexin-A in cerebrospinal fluid to diagnose narcolepsy. — Sleep, 2025. PMID 40801283.
  3. Narcolepsies, update in 2023. — Revue neurologique, 2023. PMID 37634997.
  4. Hypocretin-1/Hypocretin Receptor 1 Regulates Neuroplasticity and Cognitive Function through Hippocampal Lactate Homeostasis in Depressed Model. — Advanced science (Weinheim, Baden-Wurttemberg, Germany), 2024. PMID 39119889.
  5. Adolescent alcohol exposure increases orexin-A/hypocretin-1 in the anterior hypothalamus. — Alcohol (Fayetteville, N.Y.), 2020. PMID 32619610.
  6. Detection of reduced orexin-A/hypocretin-1 and its fragments by orexin-A "gold-standard" radioimmunoassay. — Sleep medicine, 2025. PMID 40250157.
Supplies Needed

A typical reconstitution-and-injection kit includes:

  • Lyophilized peptide vial(s) — enough for the full protocol length
  • Bacteriostatic water for reconstitution
  • U-100 insulin syringes (one per injection)
  • Alcohol prep swabs
  • A sharps container for safe disposal
Storage, Handling & Injection

Storage & handling

Lyophilized (freeze-dried) peptide is typically kept refrigerated and protected from light; once reconstituted with bacteriostatic water it is generally refrigerated at 2–8 °C and used within a few weeks. Follow aseptic technique to avoid contamination, per CDC injection-safety guidance.

Injection technique

Subcutaneous injections are usually given into the fat of the abdomen or thigh: clean the site with an alcohol swab, pinch the skin, insert at the recommended angle, and rotate sites to protect the tissue. See MedlinePlus for a step-by-step subcutaneous-injection guide.

General aseptic-technique and injection references for educational use — they are not specific to any research compound.

Orexin A Вопросы и ответы

What is Orexin A?
Orexin A (also called Hypocretin-1) is a neuropeptide produced by a small group of neurons in the hypothalamus. It plays a central role in keeping the brain awake and alert. When these neurons are lost — as happens in narcolepsy type 1 — the result is severe, uncontrollable sleepiness and other symptoms like cataplexy (sudden muscle weakness).[1] It is currently studied as a research-only compound.
How does Orexin A work?
Orexin A binds to two receptors — HCRTR1 and HCRTR2 — across multiple brain regions. This activation sustains arousal and wakefulness. When orexin signaling fails, the brain cannot reliably maintain a wakeful state.[3] Research also shows HCRTR1 influences hippocampal energy metabolism and brain plasticity, linking orexin to cognition and mood as well.[4]
What is Orexin A used for in research?
Researchers study Orexin A primarily in the context of narcolepsy — both as a disease biomarker and to understand its biology.[1][3] It is also explored in depression and cognitive impairment research[4], alcohol use disorder studies[5], and to help develop better diagnostic tests using advanced mass spectrometry techniques.[2] It is strictly a research compound, not an approved therapy.
How is Orexin A dosed in research?
There is no single standard dose — protocols vary widely by species, administration route, and research goal. Common preclinical routes include intracerebroventricular and intranasal delivery. Researchers should consult peer-reviewed literature for context-specific amounts. The dosage chart and calculator on this page can help with reference ranges and volume calculations. This information is for research purposes only.
How do you reconstitute Orexin A?
Orexin A powder is typically dissolved in sterile water or a compatible aqueous buffer. Add the solvent slowly down the side of the vial and gently swirl — never shake. Divide the solution into small aliquots, freeze at −20 °C or below, and avoid repeated freeze-thaw cycles, which degrade the peptide. Always follow the supplier's specific guidance and relevant published protocols for your experimental setup.
Is Orexin A safe?
Orexin A is a research-only compound with no established human safety or dosing profile. Preclinical studies suggest that abnormally elevated orexin signaling may impair hippocampal function and cognition in animal models.[4] This page does not provide medical advice. Anyone considering peptide research should follow institutional biosafety guidelines and consult qualified professionals before handling research compounds.