Neuropeptide S

NPS is produced by a small brainstem neuronal cluster near the locus coeruleus and signals through NPSR, raising both intracellular calcium and cAMP. Central administration in rodents increases locomotor activity and wakefulness while decreasing anxiety-like behaviour across multiple paradigms - open field, elevated plus maze, marble burying - which is a genuinely unusual dissociation, since arousal and anxiolysis normally trade off against each other. It also facilitates fear extinction, which is why it attracts interest as a PTSD target, and it interacts with orexin and corticotropin-releasing factor systems. A common human NPSR polymorphism (Asn107Ile) is associated with panic disorder and with sleep and circadian traits, which is the strongest human-relevance signal the target has. The first N-terminal residue must be serine for activity, and the peptide's brain penetration after peripheral administration is poor.

Targets: Neuropeptide S receptor (NPSR1), Amygdala fear circuitry, Orexin system, Corticotropin-releasing factor signalling

• · There is genuinely no human dose for this compound. Rodent work uses nanomole quantities delivered directly into the ventricles, which does not convert into an intranasal dose for a person by any legitimate calculation. Grey-market suggestions in the 100-500 mcg range are guesses with nothing behind them, and this page will not dress them up as anything else.

Work out your exact syringe units →

• commonUnknown in humans - no adverse-effect profile has ever been characterised— This is the honest headline. Nobody has published what NPS does to a person.
• uncommonIncreased arousal, restlessness or insomnia— Predicted from the mechanism and from rodent hyperlocomotion.
• uncommonIncreased heart rate and blood pressure— Expected from arousal-system activation and its interaction with orexin neurons.
• uncommonNasal irritation

• Pregnancy and breastfeeding - no data of any kind.
• Panic disorder - the NPSR Asn107Ile variant is associated with panic, and the target's role in human anxiety is not simply anxiolytic.
• Cardiovascular disease - the arousal mechanism and orexin interaction argue against it.
• Anyone who wants a compound with a known safety profile. This one does not have one.

• cautionorexin-a — NPS acts partly through orexin neurons; combining them stacks arousal and sympathetic activation.
• cautionselank — Both are pitched as anxiolytics but by opposing effects on arousal. The combination has no rationale and no data.

• · Heart rate and blood pressure, given the arousal mechanism.
• · Sleep duration - a compound that promotes wakefulness will quietly cost you sleep before you notice.
• · No meaningful biomarker exists for NPSR activity.

Not approved anywhere. Strictly a research reagent.

• Xu et al. 2004, Neuropeptide S: a neuropeptide promoting arousal and anxiolytic-like effects, Neuron (preclinical)
• Jungling et al. 2008, neuropeptide S-mediated control of fear expression and extinction in the amygdala, Neuron (preclinical)

The reason Neuropeptide S attracts attention is a genuine pharmacological oddity: it increases wakefulness and locomotor activity while simultaneously decreasing anxiety-like behaviour, across multiple independent paradigms - open field, elevated plus maze, marble burying. Arousal and anxiolysis almost always trade against each other, and a molecule that dissociates them is interesting on its face. NPS is made by a small brainstem cluster near the locus coeruleus and signals through NPSR, a GPCR that raises both intracellular calcium and cAMP. It also facilitates fear extinction through effects on intercalated GABAergic neurons in the amygdala, which is why it is discussed as a PTSD target, and it interacts with the orexin and corticotropin-releasing factor systems. The strongest human-relevance signal is genetic: a common NPSR polymorphism, Asn107Ile, is associated with panic disorder and with sleep and circadian traits. Note what that association actually implies, because it is usually reported as supportive and is not straightforwardly so - a functional NPSR variant associated with panic suggests the human role of this system in anxiety is more complicated than 'anxiolytic'. And then the delivery problem, which is not a footnote but the whole issue. Almost every effect described above was produced by intracerebroventricular injection in a rodent. Peripheral administration does not reach the brain well. An intranasal dose in a person has never been measured, and the compound has never been given to a human by any route in a published study. This is a research reagent that escaped into the consumer market, and the honest summary is that of everything in this class, it is furthest from being ready for use in a person.

The fundamental problem is delivery, and it is not solvable by dosing harder. Rodent work uses intracerebroventricular injection because peripheral administration does not reach the brain well - so the entire published effect profile was generated by a route no consumer can use. An intranasal dose in a person has never been measured, and the grey-market suggestions in the 100-500 mcg range are guesses with nothing behind them. There is no published dose, no dose-response data, no pharmacokinetics and no human administration study of any kind. The second issue is that the anxiolysis people are buying may not be what the human system does: the NPSR Asn107Ile variant is associated with panic disorder, which means the human role of this receptor in anxiety is not simply anxiolytic and may run the other way in some people. The third is cardiovascular - arousal-system activation with orexin interaction predicts raised heart rate and blood pressure, and nobody has measured it. The honest summary is that the adverse-effect profile of this compound in humans is not merely incompletely characterised; it has never been characterised at all.

• Neuropeptide S receptor (NPSR1) — Gq- and Gs-coupled GPCR raising both intracellular calcium and cAMP; specific affinity constants I did not verify

  The simultaneous arousal and anxiolysis that makes the compound interesting. Also the source of the sympathetic activation.

• Amygdala intercalated GABAergic neurons — Downstream circuit target

  Control of fear expression and facilitation of fear extinction. This is the PTSD-relevant finding and the best-characterised circuit mechanism NPS has.

• Orexin system — Interacting rather than binding

  NPS acts partly through orexin neurons, which means combining it with orexin-A is engaging one system twice rather than stacking two independent arousal mechanisms.

• Corticotropin-releasing factor signalling — Interacting

  Interaction with the CRF stress system, relevant to both the anxiolytic and the arousal effects and incompletely characterised.

In rodents, intracerebroventricular effects on arousal and anxiety are essentially immediate, which tells you about the receptor and nothing about what a person would experience. What happens after an intranasal or subcutaneous dose in a human has never been measured. There is no onset, duration, or dosing interval that can be stated honestly, and there is no basis for any cycling recommendation.

The combination that actually matters is with orexin-A, and it is not the synergy people assume. NPS acts partly through orexin neurons, so running the two together engages one arousal system twice and stacks the cardiovascular effects rather than combining independent mechanisms. Given that neither has a characterised human cardiovascular profile, that is a stack with two unknowns multiplying. Combining NPS with Selank has no rationale at all despite both being described as anxiolytic - they act in opposite directions on arousal, through unrelated systems, with no data on either the combination or on NPS alone in humans. The most useful thing to say about stacking here is that stacking presumes you know what the base compound does, and for Neuropeptide S nobody does.

Against orexin-A: both are arousal peptides, they interact through the same neurons, and orexin-A at least has small human intranasal studies in narcolepsy and primate sleep-deprivation data. NPS has neither. Against Selank, which is the anxiolytic comparison: Selank has a comparative human trial against a benzodiazepine and a measured mechanism in the same patients; NPS has rodent intracerebroventricular data and a genetic association that points in a complicated direction. Against a benzodiazepine, which is what the arousal-plus-anxiolysis promise is implicitly competing with: benzodiazepines sedate and impair, which is the trade NPS theoretically avoids, and they also have decades of human data, known dosing and known risks. Against everything else on this page, Neuropeptide S is the outlier in a specific way: the target biology is genuinely interesting and reasonably well characterised, and the gap between that and any usable human product is larger here than for any other compound in the class. It is a research reagent, and the most defensible thing to do with it is to find it interesting and not take it.

A 1-5 mg vial of research-grade NPS typically runs 60-200 USD, but a monthly cost cannot be stated meaningfully because there is no dose. Any figure would imply a protocol exists, and none does. Availability is limited and this is a genuinely obscure research reagent, so identity and purity risk is higher here than for anything else in this class.

• ?There has never been a human administration study of Neuropeptide S by any route. Nothing about its effects, dosing, safety or kinetics in a person is known.
• ?Almost all rodent evidence uses intracerebroventricular administration, which sidesteps the delivery problem that any consumer use has to solve.
• ?Brain penetration after peripheral or intranasal administration in humans has never been demonstrated or measured.
• ?There is no human dose. The 100-500 mcg range circulating in grey-market discussion has no derivation of any kind.
• ?The full 20-residue sequence given in the Core record is consistent with published descriptions but I did not verify it against a primary source, so the sequence verified flag is false.
• ?I did not verify specific binding affinities of NPS at NPSR1 and have not quoted any.
• ?The NPSR Asn107Ile association with panic disorder complicates rather than supports the anxiolytic claim in humans, and its practical significance for someone taking exogenous NPS is unknown.
• ?The cardiovascular effects predicted from the arousal mechanism and orexin interaction have never been measured in a human.
• ?No pharmacokinetic parameter of any kind exists in any species.
• ?The molecular weight of 2187.5 Da is plausible for a 20-residue peptide of this composition but I did not verify it against a primary characterisation.
• ?Stability and shelf life of research-grade NPS under typical consumer storage are undocumented, and the essential N-terminal serine makes degradation functionally significant rather than merely a potency loss.

• Neuropeptide S: a neuropeptide promoting arousal and anxiolytic-like effects Xu YL, Reinscheid RK, Huitron-Resendiz S, Clark SD, Wang Z, Lin SH, Brucher FA, Zeng J, Ly NK, Henriksen SJ, de Lecea L, Civelli O, Neuron, 2004 · PMID 15312648

  The foundational paper that identified NPS and its receptor and described the arousal-plus-anxiolysis dissociation. Every claim about this peptide traces here, and every effect in it was produced by central administration in rodents.

• Neuropeptide S-mediated control of fear expression and extinction: role of intercalated GABAergic neurons in the amygdala Jungling K, Seidenbecher T, Sosulina L, Lesting J, Sangha S, Clark SD, Okamura N, Duangdao DM, Xu YL, Reinscheid RK, Pape HC, Neuron, 2008 · PMID 18667157

  The circuit mechanism for fear extinction, localised to intercalated amygdala GABAergic neurons. The basis of the PTSD interest and the most mechanistically satisfying work on this peptide.

• Neuropeptide S: a transmitter system in the brain regulating fear and anxiety Pape HC, Jungling K, Seidenbecher T, Lesting J, Reinscheid RK, Neuropharmacology, 2010 · PMID 19523478

  The review that pulls the fear and anxiety work together, including the NPSR polymorphism data that is the only human-relevance signal the target has.

• Human-Specific Neuropeptide S Receptor Variants Regulate Fear Extinction in the Basal Amygdala of Male and Female Mice Depending on Threat Salience Bengoetxea X, Goedecke L, Remmes J, Blaesse P, Grosch T, Lesting J, Pape HC, Jungling K, Biological Psychiatry, 2021 · PMID 33902914

  Directly addresses the human NPSR variants in a mouse model and finds their effect on fear extinction depends on threat salience and sex. Relevant because it complicates any simple reading of the human polymorphism data.