Neuro & cognitive

Neuropeptide Y

Also called NPY, Neuropeptide tyrosine

Neuropeptide Y (NPY) is one of the most common peptides in the brain and nerves. It helps control appetite and stress responses. Small studies have tested a single nasal spray of NPY in people with PTSD and depression, with early signs of less anxiety or better mood. It is not an approved medicine.

Early human dataSome small human studies exist; evidence is limited.

New · under editorial review. Added October 31, 2026 by our automated research, with every claim sourced. A person has not checked this page yet; treat it with extra care. How we research

Drawn from its published sequence: 36 residues, one bead each.

Overview

How it works

Established: NPY binds Y-family receptors, including NPY1R and NPY2R. These G protein-coupled receptors lower cAMP inside cells and raise calcium ³. In the brain it is one of the most abundant peptides and, in animals, it stimulates eating ³. In the body it is found in nerves that tighten blood vessels; sprayed in the human nose it shrank the nasal lining for about 90 minutes ⁶. Proposed: NPY is thought to act as a natural 'resilience' signal against stress. It is reduced in the spinal fluid of people with depression and PTSD, and nasal NPY given to rats right after a traumatic stress prevented later anxiety- and depression-like behavior and fear-memory problems ²⁵. Whether nasal NPY reaches the human brain in useful amounts is not settled: in healthy volunteers, very little entered the blood ⁶⁸.

What research shows

Human randomized double-blind crossover dose-ranging trial in PTSD (26 randomized, 24 completed; single doses 1.4-9.6 mg): well tolerated up to 9.6 mg; higher doses reduced anxiety (Beck Anxiety Inventory) after a trauma reminder more than placebo, but another anxiety scale (STAI) showed no effect ¹.
Human randomized double-blind trial in major depression (n=30, on stable antidepressants, single 6.8 mg dose): depression scores fell more than placebo at 5 and 24 hours, but the main 48-hour endpoint was not met ².
Human healthy-volunteer study (n=7 and 8): nasal NPY caused long-lasting nasal blood-vessel tightening with only a small rise in blood NPY and no change in blood pressure ⁶.
Animal (rats, PTSD model): a single nasal NPY dose right after traumatic stress prevented later anxiety- and depression-like behavior and helped keep fear extinction; females needed higher doses ⁵⁸.
No large or repeated-dose human trials have been published ⁸.

Doses studied in people

Study or label	Dose used	Source
Randomized crossover single-ascending-dose trial in PTSD (n=26)	Single intranasal doses of 1.4, 2.8, 4.6, 6.8 or 9.6 mg (one cohort per dose), vs placebo	¹
Randomized double-blind trial in major depressive disorder (n=30)	Single 6.8 mg intranasal dose vs placebo	²
Healthy volunteers (n=7), absorption study	10, 50 and 100 nmol by nasal spray vs saline	⁶

Doses above are single doses from small research studies, reported for reference only; there is no approved product or tested repeated-dose regimen.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Vial math

Many research vials hold 5 or 10 mg of powder. This table shows how much ends up in each mark on a U-100 insulin syringe for common amounts of added liquid. It is arithmetic only, not a dose.

Vial	Liquid added	Concentration	Per unit (0.01 mL)
5 mg	1 mL	5 mg/mL	50 mcg	Open in calculator
5 mg	2 mL	2.5 mg/mL	25 mcg	Open in calculator
5 mg	3 mL	1.67 mg/mL	16.7 mcg	Open in calculator
10 mg	1 mL	10 mg/mL	100 mcg	Open in calculator
10 mg	2 mL	5 mg/mL	50 mcg	Open in calculator
10 mg	3 mL	3.33 mg/mL	33.3 mcg	Open in calculator

More sizes: all vial sizes · How this works: Syringes and units · Reconstitution guide.

Safety

In the PTSD trial, single nasal doses up to 9.6 mg were well tolerated; specific side effects were not detailed in the abstract ¹.
In healthy volunteers, nasal NPY did not change blood pressure and caused no reported discomfort, but it did narrow nasal blood vessels for about 90 minutes ⁶.
NPY tightens blood vessels and stimulates appetite in animals, so effects outside the brain are possible if enough is absorbed ³⁶.
Only single-dose human data exist; unknown long-term safety ⁸.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA: Not FDA-approved; used only under research protocols (e.g. NCT01533519) ¹⁹.
Compounding: Not on FDA's 503A bulk drug substances categories list (Categories 1-3, updated May 14, 2026) ⁹¹.
Sports (WADA): Not named on the 2026 WADA Prohibited List. The list's S0 class covers any substance with no current approval by any government health authority for human therapeutic use, and is prohibited at all times ⁹⁰. NPY has no such approval, so on our reading it would fall under S0 — this is our interpretation of the published list, not a WADA ruling on this peptide.
Other: No approval for NPY as a medicine was found in the sources reviewed; a 2026 review says its therapeutic potential has not yet been realised ⁸.
Sold online: Neuropeptide Y is also sold online as an unregulated "research" peptide. These products are not the material used in clinical studies and have unknown purity, dose and contents. US law requires a new drug to be shown safe and effective before it is marketed, and FDA notes that for unapproved products there is no way to know whether the label is complete and accurate ⁹². FDA has separately warned sellers of weight-loss peptides that labelling a product "for research purposes" or "not for human consumption" does not change its status when it is in fact sold for human use ⁹⁴. No FDA warning letter, import alert or anti-doping notice naming NPY specifically was found.

Rules change often. See Legal status of peptides for how these categories work.

History

Tatemoto, Carlquist and Mutt reported NPY as a new brain peptide in 1982, noting its likeness to peptide YY and pancreatic polypeptide ⁴. A 1996 Swiss study gave it by nasal spray to healthy volunteers ⁶. At Mount Sinai, a dose-escalation trial in PTSD (NCT01533519) reported in 2018 ¹, and a Karolinska/Mount Sinai trial in major depression reported in 2020 ². A phase 1/2 trial of nasal NPY in trauma patients was registered in 2019 with a planned 117 participants, but its record has not been updated since August 2019 and its status is listed as unknown ⁹. A 2026 review said the small human studies were well tolerated and showed promise at the highest dose tested, but that NPY's therapeutic potential has not yet been realised ⁸.

Common questions

Is neuropeptide Y an approved treatment for PTSD?

No. It has only been tested in small single-dose research studies and is not approved anywhere ¹⁸.

What did the PTSD study find?

In 26 people with PTSD, one nasal dose up to 9.6 mg was well tolerated, and higher doses lowered anxiety after a trauma reminder on one of two anxiety scales ¹.

Does it help depression?

In a 30-person trial, one 6.8 mg nasal dose improved depression scores at 5 and 24 hours, but not at the main 48-hour time point ².

Is NPY banned in sport?

It is not named on the 2026 WADA list. The S0 class covers substances with no current approval anywhere for human therapeutic use and is banned at all times ⁹⁰; on our reading NPY fits that description, but WADA has not ruled on it.

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Sources

Last reviewed 2026-10-31 · How we research · Found an error? See our corrections policy.