Orexin A: The Definitive Guide

What is Orexin A?

Orexin A is a natural signalling peptide made by a small group of nerve cells in the hypothalamus, the part of the brain that manages sleep, appetite and body states. Its job is to keep the brain in a steady waking state. People search for it because losing the cells that make it causes narcolepsy type 1, and because nasal sprays sold online promise sharper mornings and less need for sleep.

Two research teams found it at the same time in 1998 and gave it two names. One team called the peptides orexin A and orexin B, after the Greek word for appetite, because injecting them into a rat's brain made it eat more. [1] The other team called them hypocretin-1 and hypocretin-2, because they come from the hypothalamus and resemble the gut hormone secretin. [2] Orexin A and hypocretin-1 are the same molecule, and both names are still used.

Chemically it is a chain of 33 amino acids with the formula C152H243N47O44S4 and a molar mass of about 3,561 g/mol. It is not a plain chain: the first amino acid is closed into a ring, the last one is capped, and two disulfide bridges pin the front of the molecule into a fixed shape. It is also far more fat-soluble than orexin B, which helps explain why it crossed into the mouse brain intact while orexin B did not. [3], [4], [5], [23] Both peptides are cut from one parent protein, prepro-orexin, so a single gene produces both. [3]

Products sold as Orexin A are made in a laboratory, not extracted from brains. They are usually 5 mg vials of freeze-dried powder labelled for research use. [78], [81], [84] Some sellers pair the powder with an empty nasal sprayer, as one closed United States vendor did in 2017, and a 2025 self-experiment proposal priced an "Orexin-A+B" product from another seller. [87], [93], [98] None of that is an approved medicine anywhere (see legal status).

Typical Orexin A Protocols

Blend claim (orexin A and orexin B together). Kept apart because the page does not say how much of each peptide the amount contains.

The recurring amount in the human research is a single nasal dose of 435 to 500 nmol (about 1.5 to 1.8 mg), given once under supervision; one 2006 thesis used 100 nmol. [13], [14], [15], [100], [101] No study, label or registry describes repeated use. Websites that do list a repeated schedule mostly suggest 10 to 150 mcg once or twice a day (about 3 to 42 nmol each time), roughly 10 to 180 times less than one study dose, with one outlier at 1 mg a day; none cites a study for its amount. [107], [108], [109], [110] The rows are separate records and alternatives, not steps to move through.

• Titration: no study has tested starting low and stepping up. One dosing calculator lists beginner, moderate and aggressive tiers of 10 mcg daily, 30 mcg daily and 50 mcg twice daily, and labels them speculative. [108], [17]
• Breaks and cycles: no study has tested a course length or a pause. The same calculator lists 4 weeks on and 2 weeks off, and one page covering orexin A and B together lists 4 weeks on and 4 weeks off; neither cites a source. [108], [112], [17]
• Units: studies give nanomoles (a count of molecules); vials are sold in milligrams (a weight). With a molar mass of about 3,561 g/mol, 1 nmol weighs about 3.56 mcg. Worked example: 435 nmol × 3.56 mcg = about 1,550 mcg, or 1.55 mg, so a 5 mg vial holds about 1,400 nmol, a little over three study-sized doses, and 100 mcg is only about 28 nmol, roughly one-sixteenth of one study dose. The one infusion rate, 10 pmol per kg per minute, is about 0.036 mcg per kg per minute. [4], [13], [16] The Doserly reconstitution calculator does vial-and-volume arithmetic for peptides; it cannot turn a single research dose into a tested schedule.
• Evidence note: the study amounts come from eight single-dose reports in about 97 people (five journal papers, two university theses and one conference abstract); the schedules come from websites, not from any trial of repeated use. The cited references give the full details.

Three cautions matter more than the numbers.

Sleepiness that wrecks your day is a medical problem, not a shopping problem. Falling asleep without warning, sudden muscle weakness when you laugh or feel strong emotion, sleep paralysis or dream-like images as you fall asleep can point to narcolepsy, and diagnosis needs an overnight sleep study or a spinal-fluid test. [11] Since August 2026 there has been an approved medicine for narcolepsy type 1 that acts on the same receptor, so a diagnosis now leads somewhere. [59], [60]

The doses on selling pages are not the doses in the studies. Daily website amounts of 10 to 150 mcg are a small fraction of one study dose, one reference page understates the amounts used in human studies, another misconverts them (see the unit errors), and a third gives an intravenous amount roughly 5 to 30 times the rate used in the one human infusion. [79], [80], [107], [108], [111], [16] A 5 mg vial holds only about three single research doses, so a mix-up between nanomoles, micrograms and milligrams can put a homemade spray far off in either direction. [4], [81]

Single doses tell you nothing about repeated use. Every human study gave one dose and followed people for hours or one night. No formal study has measured blood pressure, sleep, mood or anything else after days or weeks of use. In healthy men one nasal dose increased the nerve signals that tighten blood vessels, and in healthy adults one bedtime dose made the night's sleep lighter and the next morning worse. [15], [101] Whether either matters over time is unknown.

What is Orexin A commonly used for?

Orexin A is discussed for four things: narcolepsy and other disorders of excessive sleepiness, staying sharp after a short night, needing less sleep in general, and a scattering of research ideas such as appetite, mood and cancer that come from animal work. None of these is an approved use. Only narcolepsy has been studied in people as a treatment target; the other human data are single doses in healthy volunteers, and they do not support the popular uses.

The reason the idea is attractive is simple. In narcolepsy type 1, the brain has lost 85% to 95% of the nerve cells that make orexin, and the fluid around the brain and spinal cord holds almost none of the peptide. [8], [9], [10], [11] Replacing a missing signal sounds straightforward. Getting a peptide from a nasal spray into the right brain circuits, in the right amount, at the right time, has turned out to be the hard part. [20], [26]

Narcolepsy and cataplexy

This is the only use studied in patients. Three small journal studies in people with narcolepsy type 1 used a single nasal dose. They found less dream sleep, fewer direct jumps from waking into dream sleep, better smell detection and fewer mistakes on an attention test. They did not find longer waking time or lower sleepiness scores. [12], [13], [14], [17]

In other words, the sleep architecture steadied but the daytime sleepiness stayed. The review that summarized the three studies drew that conclusion explicitly and added that orexin loss cannot be the whole story of daytime sleepiness in narcolepsy. [17]

Sleep deprivation and mental sharpness

This use traces almost entirely to one 2007 experiment in monkeys. Rhesus monkeys kept awake for 30 to 36 hours did worse on a memory task, and a nasal mist of orexin A significantly improved their performance, working better than the intravenous route and changing brain activity in the regions the task uses. [19] A university press release about that study, which mentioned interest from military sponsors, is still the reference most selling pages lean on. [89] Consumer blogs build on it too, marketing nasal orexin A to men over 40 for focus and energy, a use no human study has examined. [88]

Rat work points the same way. Nasal orexin A increased the release of two chemical messengers in the front of the brain, activated arousal-related cells and shifted attention performance in aged rats. [47], [48], [49] In people, the only direct test points the other way. A 2006 university thesis gave 14 healthy adults a single 100 nmol nasal dose: their brain waves slowed, they rated themselves less active, and they ate less of a snack, the reverse of what the animal work predicted. [100] No study in healthy people has tested alertness after lost sleep.

Sleeping less without paying for it

This is the hope behind most of the nasal sprays sold online, and it is the one claim with a direct public test. Three volunteers published a placebo-controlled self-experiment in 2026: mild sleep restriction, 100 mcg of orexin A or plain water into the nose in the morning, then mental tests during the day and sleep tracking at night. Nothing reached statistical significance, including the outcome they cared about most, whether the following night's catch-up sleep shrank. [97] They listed their own weaknesses honestly: few data points, possibly too small a dose, and peptide that may have degraded in transit and storage. [97]

The only overnight study in healthy people cuts against the idea: in a university thesis, 500 nmol taken nasally at about 10 p.m. reduced deep sleep (slow-wave sleep) and left people feeling and performing worse the next morning, which the author put down to a worse night rather than a lingering direct effect (see the study details). [101]

Appetite, weight and the gut

The name orexin comes from appetite, but the human picture is small. The one intravenous study in people slowed stomach emptying slightly, lowered the hormone leptin, raised insulin and did not change how hungry people said they felt. [16] In the 2006 thesis, a nasal dose made healthy adults eat less, not more. [100] A 2011 conference abstract from the Kiel group found that one nasal dose in people with narcolepsy type 1 raised blood sugar 90 minutes after a standard glucose drink in the 7 patients with obesity (about 160 against 126 mg/dL on placebo), with no difference in the 5 normal-weight patients. [102] In mice, treatment with orexin A reduced belly fat and, in obesity-prone animals, slowed weight gain, without clear changes in energy use. [44], [45] In rats, continuous delivery into the brain increased daytime eating but did not make them heavier. [35] Nothing here supports using it for weight.

Ideas still confined to laboratories

Several other research lines get quoted on selling pages as though they were benefits. Orexin A killed colon and pancreatic cancer cells in dishes and slowed tumour growth in mice with human tumours, although one pancreatic study reported the opposite, with cell growth being promoted. [41], [42], [43] It reduced gut inflammation in a mouse model of colitis, calmed brain inflammation after cardiac arrest or sepsis in rodents, eased motion sickness in rats and cats, and improved learning in rats with induced seizures. [46], [50], [51], [52], [54] Each is an animal or cell result in a specific model, and none has been tested in a person.

See what the human studies actually measured or how it might work.

Where do Orexin A claims and protocols differ?

The biggest gap is between the studies and the websites: the studies gave one supervised dose of 435 to 500 nmol, while websites that list a schedule suggest 10 to 150 mcg a day, a small fraction of that, repeated without any test. [13], [15], [107], [108] Here is what varies, and why each point matters.

Nanomoles or micrograms?

Research papers state amounts in nanomoles, a count of molecules. Vials are sold in milligrams, a weight. For orexin A, 1 nmol is about 3.56 mcg, so the 435 nmol used in the narcolepsy studies is about 1,550 mcg, or roughly 1.5 mg. [4], [13] Anyone converting badly can be out by a factor of a thousand in either direction. One reference page states that human studies used "25 to 100 nmol", which is not what the published reports say: the journal studies used 435 to 500 nmol, and no published human study or thesis used less than 100 nmol (see the worked conversion). [79], [13], [14], [100] Another page converts the study amounts wrongly, giving 435 nmol as about 1.9 mg and 500 nmol as about 2.2 mg; the correct figures are about 1.55 and 1.78 mg. [111], [4]

Does it even reach the brain?

This is the deepest split in the evidence, and it is unresolved.

• It crosses easily. In mice, radiolabelled orexin A injected into a vein entered the brain quickly by simple diffusion, arrived mostly intact and reached brain tissue rather than sticking to blood-vessel walls. The authors measured it as fat-soluble, which explains the passage. [23], [24]
• It barely gets there. In control dogs, intravenous doses up to 6 mcg per kg did not increase wakefulness, although doses given into the brain fluid did, and only 96 to 384 mcg per kg briefly reduced cataplexy in one dog lacking the peptide. The authors concluded that systemic orexin A hardly crosses into the brain. [26] Dogs with a broken OX2 receptor did not respond even to dosing straight into the brain fluid, so they cannot show whether the peptide gets in; an earlier report of fewer cataplexy attacks after systemic doses in such dogs remains unexplained. [26], [27] A 2018 imaging study labelled orexin A with a radioactive tracer and followed it after nasal dosing in rats and monkeys: brain exposure was poor and similar to the intravenous route, with a possible local increase in the olfactory bulbs. [20]
• The nose helps in anaesthetised rats. In that setting, nasal delivery gave the same brain levels as an intravenous infusion despite a tenfold lower blood level, and roughly 80% of the brain exposure came from direct nose-to-brain transport rather than from the bloodstream. [21]

So nasal delivery clearly beats the bloodstream for efficiency, and it clearly changed something measurable in the human narcolepsy studies. Whether enough peptide reaches the deep brain regions that control wakefulness is still argued.

Which peptide is in the bottle?

Mixed "Orexin-A+B" products have been sold, and one supplier sells a four-peptide nasal set that includes orexin A alongside three unrelated compounds. [87], [98] Orexin B is a different molecule with different behaviour (see the comparison), and in a blend no one can tell which component did anything. Research-grade suppliers also sell orexin A as a trifluoroacetate salt, which is normal for synthetic peptides but means the powder weight is not all peptide. [85]

Is a bigger dose a stronger dose?

Nobody knows: there are no dose-response data in people. The one public account of a very large amount, several milligrams followed by about 70 hours without sleep, came from someone who already had severe insomnia and felt no stimulation from the dose, so it cannot show what the dose did (see the full account). [94] It is still a reason not to treat "just take more" as a plan.

What happens when you stop Orexin A?

Nothing has been studied, because no formal study has kept anyone on it. The human studies were single doses and ended when the recording session or the following morning ended. [13], [14], [15], [16], [101]

Three things can be said honestly:

• The peptide leaves the blood fast. Its half-life in rats is about 27 minutes, and no human measurement exists. [25] Any direct effect is short.
• Most community accounts of stopping are accounts of running out. People describe the effect ending and their usual morning grogginess returning, with no reports of withdrawal symptoms. [91] One person recalled needing larger amounts over about a month for the same effect, from 50 mcg at first to 250 mcg by the end, and stopping when the vial ran out because the effect was short; this is a self-report recalled years later, not a measurement. [113]
• The closest evidence about stopping an orexin-targeting drug comes from the approved medicine, where 277 people who completed or stopped repeat-dose studies showed little sign of physical dependence. That is a different molecule taken by mouth, so it is context and not a finding about orexin A. [59]

Do nasal, injected and oral Orexin A behave the same way?

No. Route changes almost everything for this peptide, and only two routes have ever been used in people.

Intranasal (sprayed into the nose) is the route in seven of the eight human reports. Some of the spray lands on the lining high in the nose, where nerves running to the brain offer a partial shortcut past the blood-brain barrier, the tight lining of brain blood vessels that keeps most large molecules out. In rats, this route delivered the same brain levels as an intravenous infusion with a tenfold lower blood level, and most of the brain exposure came from direct transport rather than from blood. [21] The catch is that delivery depends on where the spray lands, how much liquid the nose can hold and how fast enzymes in the lining break peptides down, which is why nasal peptide products are hard to make reliable. [87]

Intravenous (into a vein) was used in the stomach-emptying study, as a slow drip. [16] Dog studies conflict: an early report found fewer cataplexy attacks after systemic doses [27], while a later one found that doses up to 6 mcg per kg did not wake control dogs and only 96 to 384 mcg per kg briefly helped one dog lacking the peptide (see the brain-entry debate). [26]

Subcutaneous (into the fatty layer under the skin) has never been used with orexin A in a published human study. In a rodent pain model, orexin A worked when given into a vein but not when given subcutaneously. [34]

Oral (swallowed) is not a route for this peptide. Digestive enzymes break peptides apart, and no study has tested swallowed orexin A. The approved orexin-2 receptor medicine works by mouth because it is a small manufactured molecule, not a peptide. [59]

Doserly

Only two routes have ever been tried in people

What each route has been tested for, in people and in animals. Human and animal research.

Intranasal · 7 human reports

In people: 100 nmol (2006 thesis), 435 nmol (2011, 2014) and 500 nmol (2009 thesis, 2022), single dosesIn animals: Monkeys about 1 mcg/kg; rats: same brain levels as a vein injection with a tenfold lower blood level; brain scans found poor brain exposure

Into a vein · 1 human study

In people: 10 pmol/kg/min infusion in 6 men (stomach emptying)In animals: Dogs: no effect up to 6 mcg/kg; a brief effect in one dog only at 96 to 384 mcg/kg

Subcutaneous · Never in people

In people: No published studyIn animals: No pain-relieving effect where a vein injection worked

Swallowed · Never tested

In people: No published studyIn animals: None; peptides are digested. The approved orexin-2 receptor medicine is a small molecule, not a peptide

Seven nasal reports and one vein infusion, all single doses. Under the skin and by mouth have never been tested in people.

How long does it last in the body?

In rats, plasma half-life was 27.1 minutes, longer than many gut peptides, with first-order kinetics and no sign of binding to peripheral tissues. [25] In people it has never been measured, and a 2026 review of the orexin system notes how variable the published measurements of circulating orexin are. [58] A 2026 laboratory study went further: with a very sensitive method, orexin A and orexin B were undetectable in blood, and the nanogram-level blood readings published previously were analytical artefacts. [56] That is a caution about measurements, not proof that an injected dose disappears instantly.

How should Orexin A be stored, and how long does it last?

There is no stability study for any consumer orexin A product, so what follows is supplier instruction, and suppliers disagree.

• Powder. Research suppliers say to keep the freeze-dried (lyophilized) powder at −20 °C (−4 °F), protected from light and moisture, and note that it absorbs water from the air. [81], [85], [86] Some sellers instead say 2 to 8 °C (36 to 46 °F) for the sealed vial. [82], [83]
• After mixing. Pages say to refrigerate at 2 to 8 °C and protect from light, and not to refreeze. Their "use within" advice ranges from 7 days to 14 to 30 days, and none cites a stability test for orexin A. [79], [82], [84] Separately, a laboratory team measuring orexins in monkey spinal fluid found both peptides "sticky": they bind to surfaces unless an acid and a detergent are added. [106]
• Why it matters here. The molecule's shape depends on two disulfide bridges, and suppliers warn that handling conditions can disturb them. [86] The volunteers who ran the self-experiment listed poor storage as one reason their result might have been null: their peptide arrived at room temperature and one shipment sat uncooled in customs for over a week. [97]

For comparison, the approved orexin-2 receptor tablet is simply stored at 20 to 25 °C, because a small manufactured molecule is far more stable than a peptide. [59]

What do we actually know about Orexin A in people?

Less than almost any compound with this much online attention. Eight reports describe giving orexin A to people, about 97 participants in total, each receiving a single dose: five journal papers, two university doctoral theses and one conference abstract. [12], [13], [14], [15], [16], [100], [101], [102] The theses and the abstract did not go through journal peer review, so they are labelled as such below, and the Kiel narcolepsy reports may share patients. One study is registered with ClinicalTrials.gov: NCT00484757, a Kiel study that began in 2007 and planned a night-time nasal dose in 15 people with narcolepsy and 15 healthy controls. Its record was last updated in 2009, its status is unknown and no results have been posted. [99] There is no phase 1, phase 2 or phase 3 programme behind the peptide. [68] Everything else in people is observation: measurements of the peptide in patients, not doses given to them.

The narcolepsy studies

All four come from one sleep-medicine centre in Kiel, Germany, and used nasal dosing in adults with narcolepsy with cataplexy. The first three are journal papers covered by a systematic review; the fourth is a conference abstract. [17], [102]

The systematic review that summarized the three journal papers concluded that orexin A reduces dream sleep and wake-to-dream transitions but does not increase wake time, and that orexin loss is therefore not the only driver of daytime sleepiness in narcolepsy type 1. [17] An editorial comment was published alongside the 2011 study. [18]

What these studies cannot tell you: whether repeated dosing helps, whether the effect lasts beyond one night, whether anyone feels better day to day, or what happens with long-term use. Each was a single dose with a few hours of follow-up in fewer than 15 people.

The studies in healthy people

In 10 healthy young men, a single 500 nmol nasal dose increased resting sympathetic nerve traffic to blood vessels, measured directly with a fine electrode in a leg nerve. Burst rate rose by about 5.8 bursts per minute against 2.1 after placebo, and total activity rose to 169% of baseline against 115%. Blood pressure, heart rate, heart-rate variability and the blood-pressure reflex response did not change during the session. [15] The authors framed this as the brain resetting the level at which it defends blood pressure, and called for work on the orexin system in high blood pressure.

In 6 healthy men, a slow infusion into a vein slowed the rate of stomach emptying without changing the lag phase or half-emptying time, lowered blood leptin, raised insulin, left the hunger hormone ghrelin unchanged and did not alter how hungry the men said they were. [16]

Two doctoral theses from the University of Lübeck add healthy-volunteer data; neither was published as a journal paper. In 2006, 14 healthy adults aged 18 to 30 received 100 nmol nasally or plain water. Brain waves slowed, people rated themselves less active and they ate less of the snack offered afterwards. [100] In 2009, 26 healthy adults received 500 nmol nasally or plain water at about 10 p.m. and slept in the laboratory. Deep sleep fell and took longer to start. The next morning they described themselves as less alert, less active, more restless and more irritable, and scored worse on finger tapping and number recall. [101] Both results run against the popular picture of orexin A as a simple energiser.

What the human data do not include

• No side-effect tables. None of the journal abstracts mentions side effects, and a systematic review of the three narcolepsy trials found that none reported any. The one report that describes unwanted effects is the 2009 thesis: a lighter night and a worse next morning after a bedtime dose. Absence of a report is not evidence of safety in studies this small. [12], [13], [14], [15], [16], [17], [101]
• No repeated dosing, no dose comparison and no long-term follow-up. [17]
• No study in people without a sleep disorder looking at sleep, alertness or mood over time. The only public attempt is the three-person self-experiment, which found nothing. [97]
• No registered trial with results. The one registered study giving the peptide, NCT00484757, spells it "Orexine A", has not been updated since 2009 and has posted no results. Other ClinicalTrials.gov searches for orexin A and hypocretin-1 return studies of orexin receptor drugs and studies that measure orexin. [68], [99]

Human studies about the peptide rather than the dose

A separate body of human research explains why the idea exists. Hypocretin-1 was undetectable in the spinal fluid of seven of nine people with narcolepsy in 2000. [8] Post-mortem brains showed an 85% to 95% loss of the cells that make it, with neighbouring cell types intact. [9], [10] A 274-patient diagnostic study set the threshold still used today: a spinal-fluid hypocretin-1 level below 110 pg/mL is diagnostic for narcolepsy, and levels above 200 pg/mL are normal. [11] Newer laboratory work has tightened the measurement, showing that older immunoassays overstated concentrations by about 5 to 50 times and that the peptide is not reliably detectable in blood at all. [56], [57]

How does Orexin A work?

The human pharmacology of the orexin system is well established, even though orexin A as a product is not. The peptide acts on two receptors on nerve cells, called OX1R and OX2R. Orexin A activates both with similar strength. [3], [32]

It excites the brain's arousal centres. The densest orexin fibres land on the locus coeruleus, a small brainstem nucleus that sets attention level, where orexin A makes cells fire faster and, in rats, increases arousal and movement. [29] Delivered into the fluid spaces of a rat's brain at the start of its sleep period, it increased waking in the second and third hours in proportion to the amount given, and at the highest amount cut dream sleep and deep sleep. [30] In rats it also increased the release of acetylcholine and glutamate, two messengers involved in attention, in the front of the brain after nasal dosing [47], and glutamate in the amygdala after intravenous dosing. [55]

It stabilises the switch between sleep states. Mice bred without orexin develop a condition that looks like human narcolepsy, and dogs with a broken OX2 receptor develop narcolepsy too. [6], [7] In mice whose orexin cells were destroyed, giving orexin A into the brain suppressed cataplexy-like attacks and increased waking for about three hours, which is the experiment that made receptor agonists worth developing. [28] In narcoleptic dogs, an early study reported that repeated systemic doses reduced cataplexy and consolidated waking [27], but a later study found that receptor-mutant dogs did not respond even to dosing into the brain fluid, and that systemic doses helped only at very high amounts, briefly, in one dog lacking the peptide. [26]

Its reach goes well beyond sleep. In rats, orexin A into the brain raised blood pressure even at amounts that only just increased eating. [33] It reinstated drug-seeking behaviour and raised the threshold for brain reward, an effect blocked by drugs that block stress pathways. [37], [38] It produced anxiety-like behaviour when injected into a specific stress-related nucleus, and people with panic anxiety were found to have higher orexin in their spinal fluid than people without. [39], [40] Infusing orexin into mouse brains raised the level of amyloid beta, the protein that clumps in Alzheimer's disease, while blocking orexin receptors lowered it. [36] It was analgesic in rodent pain models when given into a vein. [34] It also reaches the stress-hormone system: in dishes of human adrenal cells, orexin A, but not orexin B, increased cortisol release. [104]

Why an orexin-shaped drug beat the peptide. The practical problem is delivery, not biology. Peptides are large, water-loving and short-lived, and the body clears them fast. [25] The pharmaceutical answer was to build small molecules that switch the OX2 receptor on and can be swallowed. That approach produced oveporexton, approved in 2026, and alixorexton, still in trials. [59], [65], [66] The same receptor system, approached from the other direction, produced the insomnia medicines that block orexin receptors. [67]

What are the risks and unanswered questions?

Is Orexin A safe?

Its safety in people is not established. About 97 people have received it in the eight reports found, once each, with monitoring. None of the journal abstracts mentions side effects, and the review of the three narcolepsy trials found none reported. [12], [13], [14], [15], [16], [17] The one report that looked for next-day effects found some: a bedtime dose lightened sleep and left healthy adults less alert and more restless the next morning. [101] That is far too little to describe a safety profile, and it says nothing at all about repeated use.

Three specific concerns stand out.

Blood pressure control. The one study that measured it directly found that a single nasal dose in healthy men increased sympathetic nerve traffic to blood vessels, without changing blood pressure during the session. [15] In rats, orexin A into the brain raised blood pressure, and a continuous two-week infusion raised systolic pressure by about 16 mmHg on day 3 before it returned to baseline by day 14. [33], [103] Anyone with high blood pressure, heart disease or a heart rhythm problem should treat this as an open question rather than a settled one.

Stress, anxiety and reward circuits. Animal work ties orexin signalling to panic-like responses, anxiety behaviour and relapse to drug seeking, and people with panic anxiety have higher spinal-fluid orexin. [37], [38], [39], [40] The label of the approved orexin-2 receptor medicine states that it has potential for abuse; in an abuse-potential study in people who use stimulants recreationally, doses 1.5 to 7.5 times the maximum daily dose produced higher drug-liking scores than placebo, similar to or lower than phentermine, a Schedule IV stimulant, and its controlled-substance classification was still pending when its label was issued. [59] That is a different molecule, but it is the closest human read on what stimulating this system repeatedly can do.

Sleep architecture. Taking a wake-promoting substance late in the day is a straightforward way to wreck a night's sleep, and for orexin A this has been measured: 500 nmol by nose at about 10 p.m. reduced deep sleep in healthy adults and left them feeling worse the next morning. [101] In the approved medicine's phase 3 trials, insomnia occurred in 58% of treated patients, with about 90% of cases starting within the first two days. [59] One community report describes about 70 hours without sleep after a very large amount, but from someone who already had severe insomnia, so the link is uncertain (see the report). [94]

What problems have actually been reported?

Nothing serious. None of the journal abstracts mentions adverse events, and no case report of harm from orexin A was found. [12], [13], [14], [15], [16], [17] The 2009 thesis recorded less deep sleep and a worse next-morning mood after a bedtime dose, and the 2011 abstract recorded a higher blood-sugar rise after a glucose drink in patients with obesity. [101], [102] Public accounts describe a burning sensation in the nose after spraying, a brief lift followed by a "light crash", no effect at all in several people, and one long sleepless stretch in someone with existing insomnia (see community reports). [91], [92], [94] These are self-reports from people mixing their own sprays from research powder, with no way to verify what was in the bottle.

Could product quality change the risk?

Yes, and this is a bigger practical risk than the peptide itself. Vials sold as research chemicals are not medicines: nobody checks them for sterility, correct content or contaminants on your behalf. Prices and labels vary widely across sellers, from research-catalogue suppliers selling 1 mg datasheet vials to consumer sites selling 5 mg vials, some with an empty nasal sprayer. [78], [81], [85], [87] Health Canada warns that unauthorized peptide products may contain too much, too little or none of the stated ingredient, may contain unlisted ingredients or contaminants, and may be improperly made or stored. [73] The volunteers who ran their own trial could not rule out that their peptide had degraded before they used it. [97]

Is Orexin A legal? Is it FDA-approved?

Checked September 26, 2026. Rules differ by country and change quickly. A "research use only" label does not make a product legal to sell or safe to use.

United States. Orexin A is not an approved medicine: a search of the FDA's approved-drug database returns no product containing orexin or hypocretin as an active ingredient. [70] It is not among the substances nominated for pharmacy compounding under section 503A (list updated May 14, 2026) and is not on the FDA's list of compounding substances that may pose significant safety risks (content current April 22, 2026). [69], [71] Neither absence is a ruling on whether selling it is legal. Sellers offer it as "research use only" material. [78], [81]

United States, the approved alternative. Oveporexton (brand name Orzeyful), a tablet that activates the orexin-2 receptor, was approved on August 5, 2026 for narcolepsy type 1 in adults, under application NDA 220860, with priority review and orphan designation. Its own label records that the controlled-substance schedule was still to be determined. [59], [60], [66]

Canada. A search of Health Canada's Drug Product Database for orexin, hypocretin and oveporexton returns no authorized product. [72] Health Canada's April 2026 advisory warns the public not to inject peptide products bought online, because unauthorized products are not assessed for safety, effectiveness or quality, and states plainly that a "research use only" label does not make a product legal or exempt from the rules. [73]

Australia. No authorised orexin A product was found in the sources checked; a search of the Australian Register of Therapeutic Goods itself was not run. The Therapeutic Goods Administration's April 2026 guidance on unapproved peptides does not name orexin A. It states that such products are not included in the Australian register and "have not been evaluated for safety, quality or effectiveness by the TGA". [74]

United Kingdom and Europe. No authorised product was found in the sources checked: a search of GOV.UK, which covers the medicines regulator, returns no record for orexin A or hypocretin apart from one unrelated document, and the regulator's product database itself was not searched. [75] Sellers in the United Kingdom list it as a research chemical with a safety data sheet stating that it is not for human use. [81]

Is Orexin A banned in sport? Does it show up on a drug test?

Orexin A is not named on the World Anti-Doping Agency's 2026 Prohibited List or on the 2027 list that takes effect on January 1, 2027. [76], [77] Category S0 bans at all times any pharmacological substance "not addressed by any of the subsequent sections of the List" and with no current approval by any government health authority for human therapeutic use, and the 2027 list adds "peptides" to its examples of that category. [77] Orexin A has no such approval, so athletes subject to testing should assume S0 applies; because it is wake-promoting, the in-competition stimulant section (S6) could also be argued to cover it. [77] One reference website states flatly that orexin peptides are "not on the Prohibited List", which is true as a matter of naming and misleading as a matter of rules. [80] None of the sources reviewed describes a routine test that detects orexin A.

Who should be especially cautious?

These groups have no safety data at all. That is a reason for caution, not proof of harm.

• Anyone with high blood pressure, heart disease or a heart rhythm disorder, because of the sympathetic nerve finding in healthy men and the blood-pressure findings in rats. [15], [33], [103]
• Anyone with diabetes or obesity, because one small report found a higher blood-sugar rise after a glucose drink in patients with obesity. [102]
• Anyone with an anxiety or panic disorder, given the animal work and the higher spinal-fluid orexin found in people with panic anxiety. [39], [40]
• Anyone in recovery from a substance use disorder, given the reinstatement findings in animals and the abuse-potential warning on the approved orexin-2 receptor medicine. [38], [59]
• Anyone with suspected or diagnosed narcolepsy who has not seen a specialist. Diagnosis changes what is available, including an approved medicine. [11], [59]
• Children and teenagers, and anyone pregnant or breastfeeding. Never studied. The approved medicine has not been established as safe or effective in children either. [59]
• Competitive athletes. See the anti-doping section above. [77]

Has Orexin A been tested alongside other medicines?

No. There is no interaction study of any kind. What can be said is indirect and worth raising with a pharmacist or doctor:

• Orexin receptor blockers used for insomnia, such as suvorexant, act in the opposite direction, and suvorexant is contraindicated in narcolepsy. [67]
• Stimulants and wake-promoting medicines used for narcolepsy work through different mechanisms; combining them with anything that raises sympathetic activity has not been studied. [15], [17]
• The approved orexin-2 receptor tablet is contraindicated with strong CYP3A inhibitors and needs a dose reduction with moderate ones, which shows that this class interacts with common medicines even though orexin A itself has never been tested. [59]

Bring a complete list of everything you take to a pharmacist or doctor before adding anything. Health Canada notes that unauthorized injectable products can interact with other medicines. [73]

What should be monitored while using Orexin A?

No regulator has written a monitoring plan for orexin A, and there is no approved label to borrow from. What follows is what the studies measured, plus what the label of the approved orexin-2 receptor medicine requires, clearly separated. It is background for a conversation with a clinician, not a personal testing plan.

What the human studies measured

The narcolepsy studies recorded overnight sleep with polysomnography, daytime ability to stay awake, attention tests and sleepiness scores. [13], [14] The healthy-volunteer study recorded sympathetic nerve activity, blood pressure, heart rate and heart-rate variability. [15] The infusion study recorded stomach emptying, appetite ratings, insulin, leptin, ghrelin and glucose. [16] The theses recorded brain waves, mood, eating, overnight sleep and next-morning mental tasks, and the 2011 abstract recorded blood sugar during a glucose drink test. [100], [101], [102] None of them tracked anything beyond the next morning.

What the approved medicine's label requires

Those numbers belong to a swallowed small molecule that switches on one orexin receptor for many hours a day, not to a nasal peptide. They are listed because they are the only systematically collected human safety data for stimulating this system, and because they point at what would be worth watching: sleep, blood pressure, and unexplained muscle pain.

Two things are worth raising with a clinician regardless. First, persistent daytime sleepiness deserves a diagnosis, because a sleep study or spinal-fluid test changes what treatment is possible. [11] Second, any new chest symptom, fainting, severe headache or sudden change in blood pressure after taking anything bought online is a reason to seek medical care and to say what was taken. [73]

What do people in public communities report?

Public discussion of orexin A is old, thin and unusually honest about failure. Most of it dates from 2017 to 2019, when one United States vendor sold 5 mg vials with spray bottles; that vendor closed, and posts after it closed are mostly people asking where to get it or asking whether the new medicines will reach them. [91], [92], [93], [95], [96] Selected discussions are not a survey of users, and people post more readily about dramatic results than about nothing happening.

What the positive reports look like

• A person on a nootropics forum described 100 to 130 mcg a day as a spray, saying it removed morning grogginess and produced a calm, wide-awake feeling. They could not say how long the effect lasted, because by mid-morning they usually felt awake anyway. [91]
• A person with narcolepsy described using it as needed rather than daily, saying it cleared mental fog within a minute or two on bad mornings but did not replace their prescribed stimulant. [92]
• Another person with narcolepsy posted a diary of their first days, then updated later: their general sleepiness did not go away, but they had no cataplexy episodes while using it and felt their other medicines worked better. [93]

Does everyone notice a difference?

No, and the careful accounts are the negative ones. One person with narcolepsy in a 2017 thread said they felt worse, "hopelessly tired since the first day on it". [92] A 2023 thread shows the more common pattern now: someone with undiagnosed daytime sleepiness asked about trying it, and the replies pushed them toward a sleep study instead. [95] Several posters in the older threads reported nothing at all, including one who worked through a whole vial at a range of amounts and could still nap normally. [94] Another described a brief five-minute lift followed by a small crash. [91] The only placebo-controlled public test found no significant effect (see the self-experiment). [97]

What about unwanted effects?

Burning in the nose after spraying, the crash described above, and one longer story. A person who called themselves a non-responder to most substances, and who had severe insomnia at the time, felt nothing at ordinary amounts, then took several milligrams at once. They felt no stimulation but went about 70 hours without sleep; they said they felt less tired than a normal sleepless stretch would leave them, and that afterwards their insomnia eased by an hour or two of sleep a night. With existing insomnia and no felt effect from the dose, the link to orexin A is uncertain, and it is a single unverified self-report. [92], [94] One thread asked specifically whether it raised anxiety, and the people who replied said it had not for them, which is weak evidence in both directions given how few replied. [94] Nobody in these threads had their product tested.

Why the community stories are hard to use

Almost every account involves a homemade spray from research powder, with no way to know the concentration, the sterility or whether the peptide survived shipping and storage. Doses are quoted in micrograms, sprays or "1 mcg per kg twice a day", and often the poster is also taking prescribed stimulants for a diagnosed condition. [92], [93] Being made by the body does not make an unregulated product safe.

In community education groups, orexin comes up mostly in passing, inside broader sleep lessons: as the biology behind narcolepsy, as the target of the newly approved medicine, and as the system the insomnia blockers switch off. No lesson gives an orexin A schedule. Member discussions are just as thin. When people ask for a protocol, the replies say no one knows of one, that the peptide is hard or impossible to find for sale, and that people chasing wakefulness use other drugs instead. The only first-hand mentions involve ready-mixed nasal sprays that did not state how much peptide each spray held. One person felt more awake in the morning after one spray and then two, but it was only the second day, they were taking other nasal peptides at the same time, and the bottle looked almost empty when it arrived. Nobody posted a follow-up. The other mention was a list of benefits that read like product marketing, from a spray that may have contained other ingredients. None of these discussions reports a dose in micrograms, how long anyone used it, any side effects or what happened after stopping.

How can you judge a wakefulness story?

Ask: was there a diagnosis, or is this someone tired for ordinary reasons? What exactly was in the bottle, and who made it? How much, by which route, and at what time of day? What else was running at the same time: prescribed stimulants, caffeine, a new sleep schedule, a holiday? Was anything measured, or is it a morning impression? And what did the same person say three months later? On these threads, the follow-ups are consistently less impressive than the first post.

How does Orexin A compare with Orexin B and the orexin medicines?

Four things get called "orexin" in online discussion, and they behave very differently. Two are the natural peptides, one is a new medicine that switches the same receptor on, and one is a family of sleeping tablets that switch it off.

Doserly

Orexin A and orexin B: one gene, two different peptides

Both are cut from the same parent protein, prepro-orexin. Cell and animal research.

Size and shape

Orexin A (this guide): 33 amino acids, two disulfide bridges, ring-capped start and amidated endOrexin B: 28 amino acids, a straight chain with no disulfide bridges, so its shape is less fixed

Receptors

Orexin A (this guide): OX1 and OX2 about equallyOrexin B: Matches A at OX2; 5 to 100 times weaker at OX1, depending on the test

Survival and brain entry

Orexin A (this guide): Crosses from blood into the brain by simple diffusion, mostly intactOrexin B: Injected into the blood of mice, rapidly broken down and no intact peptide detected in brain; no significant spinal-fluid rise after brain dosing; not detected in human spinal fluid by two sensitive methods; never tested by the nasal route

Orexin B has its own guide: Orexin B.

Orexin B favours OX2 and, injected into the blood of mice, was broken down before any intact peptide reached the brain.

Orexin A and Orexin B are not interchangeable, even though one gene makes both. Orexin A is longer and held in a fixed shape by two disulfide bridges; orexin B is a straight chain with no disulfide bridges, so its shape is less fixed, and it works mainly through the OX2 receptor, being roughly 5 to 100 times weaker than orexin A at OX1 depending on the test. [1], [3], [32], [105] Injected into the blood of mice, orexin A crossed into the brain intact while orexin B was broken down first; orexin B has never been tested by the nose, and no published study has given it to people. [23] The figure above and the Orexin B guide give the fuller comparison; there is no evidence that the orexin B in an "Orexin A+B" blend reaches the brain or adds anything.

The gap between the peptide and the medicine is the point. Oveporexton does what orexin A was hoped to do: in two phase 3 trials people with narcolepsy type 1 stayed awake 14 to 20 minutes longer on a standard test (placebo changed by less than a minute), and weekly cataplexy attacks fell by a median 79% to 89%, against 28% to 39% on placebo. [62] The peptide, given once into the nose, steadied dream sleep but did not increase wake time. [13], [14], [17] The two cannot be compared directly: the tablet was taken twice daily for 12 weeks, while the peptide was given once, and how much reaches the brain from the nose is disputed. [20], [21], [59], [62] Getting there took a failure as well: an earlier drug in the class, TAK-994, was stopped in phase 2 after serious liver injury. [63], [64]

Common questions about Orexin A

Is Orexin A the same as hypocretin-1?

Yes. Two laboratories described the same peptide in 1998 and named it differently: orexin A from one group, hypocretin-1 from the other. [1], [2] Both names appear in research papers, product labels and clinical practice, and the spinal-fluid test used to diagnose narcolepsy is usually called a hypocretin-1 test. [11] Orexin B and hypocretin-2 are likewise the same molecule as each other, and a different molecule from this one (see the comparison).

Does Orexin A make you need less sleep?

No evidence says so. The only public test of that exact question was a placebo-controlled self-experiment by three volunteers, who restricted their sleep and took 100 mcg nasally or plain water in the morning. Neither the following night's catch-up sleep nor any mental test differed significantly, and the authors published the null result themselves. [97] In healthy adults, 500 nmol taken at bedtime made deep sleep lighter and left people less alert the next morning, which is the opposite of a better night. [101] In monkeys, nasal orexin A significantly improved memory-task performance after 30 to 36 hours awake, which is a different thing from removing the need to sleep. [19] See what it is used for.

Is Orexin A a nasal spray or an injection?

Both exist, and neither is a medicine. Seven of the eight human reports sprayed it into the nose, and one gave it as a slow drip into a vein. [13], [14], [15], [16], [100], [101] Sellers offer 5 mg vials of powder sold for making nasal sprays, sometimes with other peptides in the same vial. [78], [84], [87] There is no published human study of a subcutaneous injection of orexin A, and in a rodent pain model it worked intravenously but not by that route. [34] See how routes compare.

How long does Orexin A take to work, and how long does it last?

In the human studies the measurement windows were short: nerve activity was measured 30 to 45 minutes after the nasal dose, and sleep recordings began the same evening or that morning. [13], [14], [15] Its half-life in rat blood is about 27 minutes and has never been measured in people. [25] Community accounts describe an effect within minutes that fades within hours, which fits a short-acting peptide but is not a measurement. [91], [92]

Is Orexin A the same as the new narcolepsy tablet?

No. Oveporexton, approved in the United States in August 2026, is a manufactured small molecule that switches on the OX2 receptor and is swallowed. Orexin A is the natural peptide itself. [59], [66] They act on overlapping targets, but only the tablet has been through large trials, and only the tablet has a label with doses, warnings and monitoring. [59], [62] See the comparison.

Is it legal to buy Orexin A?

It depends where you are, and nowhere is it an approved medicine. In the United States it is sold as a research chemical and is not in the approved-drug database or on the FDA compounding lists. [69], [70], [71] In Canada there is no authorized product, and Health Canada warns the public against injecting peptides bought online. [72], [73] No authorised product was found in the Australian or United Kingdom sources checked, and Australia's regulator says unapproved peptide products have not been evaluated for safety, quality or effectiveness. [74], [75] A "research use only" label is a statement about how a product is sold, not a safety assurance. See the dated legal summary.

Does Orexin A show up on a drug test?

Not on a standard drug test, and no routine test for it was described in any source reviewed. For athletes, that is not the same as being allowed: orexin A is not named on the World Anti-Doping Agency's 2026 or 2027 lists, but category S0 covers any substance that no other section addresses and that lacks approval from a government health authority, and the 2027 list names peptides as an example. [76], [77] One website's claim that orexin peptides are simply "not on the Prohibited List" ignores that rule. [80]

Can Orexin A be combined with modafinil or other stimulants?

Nothing has been studied. There is no interaction study of orexin A with any medicine. [17] The general caution is specific rather than vague: one nasal dose in healthy men increased sympathetic nerve traffic, so stacking it with other stimulants means combining two unmeasured effects on the same system. [15] Anyone taking prescribed medicines for narcolepsy, blood pressure or mental health should raise the question with the prescriber rather than experiment. See risks.

Glossary

Plain explanations of the route, dosing and research terms used in this guide. Underlined terms in the text link here.

Adverse event

A harmful or unwanted medical event reported after someone used a treatment. A report alone does not prove the treatment caused it.

Agonist

A substance that switches a receptor on, copying the body's own signal. Orexin A is an agonist at both orexin receptors; oveporexton is a manufactured agonist at one of them.

Amino acid

A small chemical building block. Chains of amino acids make up peptides and proteins. Orexin A is a chain of 33.

Amyloid beta

A protein fragment that builds up in clumps in the brains of people with Alzheimer's disease. In mice, its level in brain fluid rose during wakefulness and after orexin infusion.

Animal study

Research in animals such as rats, mice, dogs or monkeys. It shows what a substance does in a living body, but results in people can differ.

Antagonist

A substance that blocks a receptor so the body's own signal cannot act on it. The insomnia medicines suvorexant and lemborexant are orexin receptor antagonists.

Bioavailability

The share of a dose that reaches the bloodstream, or for a brain-acting peptide the target tissue, in active form. For orexin A it has not been measured in people by any route.

Blood-brain barrier

The tight lining of the brain's blood vessels, which keeps most large molecules in the blood from entering brain tissue. It is the main obstacle for peptide treatments aimed at the brain.

Cataplexy

A sudden, brief loss of muscle strength triggered by strong emotion such as laughter, while the person stays awake. It is a defining feature of narcolepsy type 1.

Cell study (in vitro)

Research on cells grown in a dish. It gives early clues about biology, but it is far from proof of benefit in people.

Cerebrospinal fluid (CSF)

The clear fluid around the brain and spinal cord. It is sampled by a lumbar puncture, and its hypocretin-1 level is used to diagnose narcolepsy type 1.

Compounding

A pharmacy making a medicine for an individual patient from raw ingredients. In the United States, pharmacies may only compound with bulk ingredients on FDA's allowed lists; orexin A is not on them.

Controlled trial

A study that compares people who receive a treatment with a similar group who do not, often receiving a placebo instead. In a crossover design, each person receives both in turn.

Course and cycle

A course is a planned period of use; a cycle is a course followed by a break, such as 4 weeks on and 4 weeks off. No study has tested any course or cycle of orexin A.

Crossover

A study design in which each person receives both the treatment and the comparison, such as a placebo, at different times, so each person serves as their own control.

Daily total

All the amounts given in one day, added together. For example, 50 mcg twice daily is a 100 mcg daily total.

Deep sleep (slow-wave sleep)

The deepest stage of non-dream sleep, when brain waves are slow and large. It is linked to feeling rested. In one study, a bedtime dose of orexin A reduced it.

Disulfide bridge

A chemical link between two sulfur-containing amino acids that pins part of a peptide into a fixed shape. Orexin A has two; orexin B has none.

Dose

The amount given at one time. For orexin A, human studies stated doses in nanomoles, while websites use micrograms.

FDA

The United States Food and Drug Administration, the regulator that approves medicines and oversees compounding pharmacies. It has not approved orexin A.

Freeze-dried (lyophilized)

Dried by freezing and removing the water, leaving a powder. Research peptide vials are sold this way and mixed with liquid before use.

Half-life

The time it takes for the measured level of a substance in the blood to fall by half. It is not the same as how long an effect lasts. For orexin A it is about 27 minutes in rats and unmeasured in people.

Hypothalamus

A small region deep in the brain that regulates sleep, appetite, body temperature and hormone release. Orexin-producing cells sit in its lateral part.

Intracerebroventricular (ICV)

Injected straight into the fluid-filled spaces of the brain. It is used in animal research to bypass the blood-brain barrier, and it is not a route anyone could use at home.

Intranasal

Sprayed or dropped into the nose. This is the route used in seven of the eight human orexin A reports.

Intravenous (IV)

Given directly into a vein, usually as an injection or a slow drip. One human orexin A study used a slow drip.

Investigational

Still being studied and not approved by a regulator, such as the FDA, to treat any condition.

Leptin

A hormone released by fat tissue that signals energy stores to the brain. An orexin A infusion lowered blood leptin in one small human study.

Loading phase

A period of higher or more frequent doses at the start of a course, meant to build up an effect quickly. No source describes one for orexin A.

mcg and mg

Micrograms and milligrams. 1 mg equals 1,000 mcg. Check which unit a page means: for orexin A the journal studies used about 1,550 to 1,780 mcg, which is 1.5 to 1.8 mg.

Molar mass

The weight of one mole of a substance, given in grams per mole. It is what lets you convert between a count of molecules (nanomoles) and a weight (micrograms).

Nanomole (nmol)

A way of counting molecules rather than weighing them. For orexin A, 1 nmol weighs about 3.56 micrograms, so 435 nmol is about 1.5 mg.

Narcolepsy type 1

A long-term neurological condition with overwhelming daytime sleepiness and cataplexy, caused by the loss of most orexin-producing brain cells.

Peptide

A short chain of amino acids. Peptides are usually broken down quickly in the body and do not survive being swallowed.

Pharmacokinetics

How the body absorbs, moves, breaks down and removes a substance. For orexin A, no human data exist.

Picomole (pmol)

A thousand times smaller than a nanomole. Infusion rates are often given in picomoles per kilogram of body weight per minute.

Placebo

A dummy treatment with no active ingredient, used as a comparison in studies. In the 2014 orexin A study the placebo was sterile water sprayed the same way.

Polysomnography

An overnight sleep recording that tracks brain waves, breathing, muscle activity and eye movements to show which sleep stages someone passes through.

Preclinical research

Studies done before research in people: cell studies, tissue cultures, computer models and animal studies.

Prepro-orexin

The parent protein that cells cut up to release orexin A and orexin B. One gene makes both peptides.

Randomized

Assigned to treatment or comparison by chance, so the groups start out alike. The narcolepsy studies randomized the order in which each person received the peptide and the placebo.

Receptor

A protein on a cell that recognizes a specific signal and changes the cell's behaviour when the signal arrives. Orexin A acts on two: OX1R and OX2R.

REM sleep

Rapid eye movement sleep, the stage in which most vivid dreaming happens and the body's muscles are largely switched off. In narcolepsy it intrudes into waking.

Research use only

A label on products sold for laboratory research. It does not mean a product is approved, tested for human use or legal to sell as a medicine.

Subcutaneous (SC)

Injected into the fatty layer just under the skin. No published human study has given orexin A this way.

Sympathetic nerve activity

Signals from the part of the nervous system that prepares the body for action, including nerve traffic that tightens blood vessels and supports blood pressure. One orexin A study measured it directly in a leg nerve.

Systematic review

A study that searches for all research on a question using set rules and summarises it. The orexin A review found three narcolepsy trials, all from one centre.

Titration

Starting with a lower amount and adjusting it step by step according to response and side effects. No study has tested titration for orexin A.

WADA

The World Anti-Doping Agency, which publishes the list of substances banned in sport.

Explore more of the research

Go deeper into the experiments behind the claims.

Across this guide, the citations include 63 original research reports on orexin A and the orexin system: 8 human administration reports (including two university theses and a conference abstract), 6 human observational or diagnostic studies, 4 trials of orexin receptor medicines, and about 45 animal, cell and laboratory studies. Report counts are not counts of independent findings: most of the human reports come from two research groups.

How this guide was researched

This guide is built from a thorough review of the sources cited throughout it: published scientific studies, a systematic review, trial-registry searches, regulatory documents and official labels, product and protocol pages, and public forum discussions. We also reviewed community education groups where people discuss sleep, wakefulness and peptides.

The guide cites 113 sources, including 63 original research reports. Each type of source answers a different question. Studies show what researchers measured. Product and protocol pages show what is being sold and claimed. Personal accounts show what individual people experienced. Every numbered citation links to its entry below, labeled by source type.

How this guide was made

Research and drafting were AI-assisted. Every cited source was checked against the original, and the guide was reviewed and edited by Doserly before publication. It has not had an independent clinical review, and Doserly does not currently have medical reviewers. Doserly makes a medication and health-tracking app and runs Doserly Academy, both of which are promoted in this guide. Read our editorial policy for how guides are researched, updated and corrected.

This guide is for educational purposes. It summarizes what the reviewed sources report so the research is easier to understand; it is not medical advice. For a deeper dive, or to check any point for yourself, go straight to the cited sources.

Explore the sources