Peptide YY_Dosage, benefits & legal status
Also known as PYY, PYY3-36, PYY1-36, peptide tyrosine tyrosine, PYY(3-36)
A hormone whose effect survives replication in people and keeps failing to become a medicine.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Peptide YY?
Plain language first. The technical label stays, but it never stands alone.Overview
This is the hormone your gut releases to tell you a meal has happened. Give it back into a vein and people eat roughly a third less at the next meal, in obese and lean subjects alike, and that has been shown in a proper randomized study. That is a real finding that has survived scrutiny. What has not worked is turning it into a product. The dose that suppresses appetite also causes nausea, the injected-under-the-skin route produced no change in food intake at all, and the one analog that reached late testing added very little on top of semaglutide.
Peptide YY is a 36-residue gut hormone released from endocrine cells of the lower intestine after a meal. Its precursor is 97 residues, and UniProtKB P10082 annotates two mature forms: peptide YY at residues 29 to 64 of the precursor, and peptide YY(3-36) at 31 to 64, a 34-residue form. Both end in an amidated tyrosine. The shorter form is the one that matters pharmacologically: it is an agonist at the Y2 receptor, encoded by NPY2R, and Y2 is the receptor that carries the appetite effect.
What it's used for
Nothing. It is a natural hormone with no approved product. It has been given in research infusions and in one nasal spray trial, and the gut hormone itself is not sold as a treatment.
How does Peptide YY work?
What it does in the body, and where.This is one of the better worked-out appetite signals in human biology, and the gap between understanding a signal and selling one is the whole story of the page.
- 01Where it comes fromEndocrine cells in the lower gut release peptide YY in proportion to the calories that arrive. The full 36-residue form is trimmed to the 34-residue 3-36 form, and that trimming changes which receptor it prefers.
- 02Why the shorter form is the active onePeptide YY binds several receptors in the neuropeptide Y family. The trimmed 3-36 form is selective for Y2, and Y2 is where the appetite effect sits. The genetic evidence came with the original work: in mice lacking the Y2 receptor, the food-intake effect disappeared.
- 03The receptor you have already met on this siteY2 is the NPY2 receptor that BI 3034701 adds to GLP-1 and GIP as its third target. That drug exists because this hormone's receptor is a credible appetite brake. Reading the two pages together is the point: one is the natural signal, the other is an attempt to engineer around its problems.
- 04Why nothing has been approvedNausea tracks the effect rather than separating from it, so the useful dose is close to the intolerable one. Delivery has also been unkind. A nasal spray reached phase 2 and went no further, and subcutaneous injection, the route that would have made a practical product, produced no change in energy intake at all.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
What is solid in people
peer-reviewed-human- Human trialA double-blind, placebo-controlled crossover study in 12 obese and 12 lean adults found caloric intake at a buffet lunch fell 30 percent in the obese group and 31 percent in the lean group, both P less than 0.001. Twenty-four-hour intake fell too, and ghrelin dropped.
- Human trialThe paper's own conclusion is the part usually left out: obese subjects were not resistant to the effect, and their endogenous peptide YY was lower, correlating negatively with body mass index.
- Human trialThe earlier 2002 human work reported a 33 percent reduction in food intake over 24 hours, and showed in mice that deleting the Y2 receptor removed the effect.
The replication argument, stated accurately
Research only- No dataIn 2004 a 42-author comment in Nature reported that many laboratories could not reproduce the food-intake result. Its title names the scope: the question was whether the hormone decreases food intake in rodents.
- No dataSo the dispute was about the animal data. The human infusion findings were not the subject of it, and they have been reproduced in people more than once.
- No dataNeither paper was retracted. The 2004 erratum attached to that record is a correction notice. Anyone describing peptide YY research as retracted or debunked has the history wrong.
Why it never became a product
tested-and-failed- Human trialNausea limits the dose. In one intravenous study at an appetite-suppressing rate, only 4 of 24 participants completed that arm, the rest stopping because of nausea.
- Human trialSubcutaneous injection, the route that would make a usable product, was tested in obese men and changed energy intake not at all. Satiety ratings moved; eating did not.
- Human trialA nasal spray reached a completed phase 2 trial with 551 subjects in 2007 and 2008 and no product followed.
- No dataDevelopment moved to engineered analogs. The most advanced, covered on this site's PYY1875 page, added little weight loss on top of semaglutide and was dropped.
Two opposite errors circulate about this hormone. The first is that peptide YY research was debunked: it was not, and nothing was retracted. A 42-author comment in 2004 reported failure to replicate the result in rodents, by its own title, and the human infusion findings were not what it questioned. The second error runs the other way, quoting the 30 percent reduction in food intake as though it described a usable treatment. That figure comes from an intravenous infusion in a research setting, the dose that produces it also produces nausea, and the practical route failed outright: injected under the skin, peptide YY changed energy intake not at all. There is also a sequence trap. UniProt's canonical sequence has arginine at mature position 9, while the FDA substance registry and major vendors list glycine there. That is not an error in either place. UniProt annotates the glycine form as a natural variant, dbSNP rs229969, so a certificate showing glycine at position 9 is describing a real human variant rather than the wrong peptide.
The published record
Papers and trials about Peptide YY
Searched: peptide YY, PYY3-36.
Left out: PYY (alone) (thousands of papers spanning gut physiology, and the abbreviation also collides with unrelated uses); neuropeptide Y (a related but different peptide with its own very large literature); Y2 receptor (the receptor, shared with BI 3034701 and neuropeptide Y work); gut hormone (a class term covering GLP-1, GIP, ghrelin and others); PYY1875 (the Novo Nordisk analog, which already has its own slug).
193 papers tagged human · 116 not reviews or lab · 33 clinical trial publications
43 registered trials · 1 with posted results
Furthest stage reached: Phase 2, completed, no results posted
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Peptide YY
Evidence
Category
Weight loss and metabolic
Common vial
Varies
Half-life
Minutes in blood
How much, and do you cycle it?
The range, and whether you take breaks.No established dose, not applicable. Not established No range
No dose or schedule exists in people outside research infusions, and no product has been approved.
Minutes in bloodNo figure
No specific figure is quoted here because none was read from a primary source. Gut hormones of this kind are cleared within minutes, consistent with every study having to use continuous infusion rather than a single injection to produce an effect.
You can compare this against the whole library to see where it sits.
What does it cost?
Typical dose and cost, in plain numbers.Peptide YY is not injected in the forms covered here
Route: not taken as a treatment. No established dose. Research infusions were given by vein at rates set per kilogram per minute under monitoring, and at effective rates nausea was common enough to end one study arm for most participants. Those are infusion rates for a research setting, not doses, and any figure offered as a peptide YY dose would be invented.
How do you store it?
Before mixing, and after.Nothing to store: it is not taken as a treatment.
Peptide YY is not used as a medicine or a supplement, so no home storage question arises. Laboratory suppliers ship research material frozen and state their own handling conditions on the certificate that comes with it.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 36% charged residues, 36% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- Any self-administered use: there is no product, no established dose and no safety monitoring, and the effective doses in studies caused substantial nausea
- Expecting weight loss from an injection under the skin: that route was tested and changed food intake not at all
Stop and get help
- Not applicable. It is not taken as a treatment
Common effects
- Nausea, at the doses that reduce appetite
- Reduced food intake at the next meal and over the following 24 hours, when given into a vein
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Peptide YY approved?
And where the numbers on this page come from.No. Peptide YY is not approved for any use, anywhere. It is sold labeled for laboratory research only, and there is no legal route to buy it for human use.
- Approval statusResearch only
- RouteNot taken as a treatment
- Checked25 October 2026
- DoseNo dose has been established in people.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
What has happened recently
No peptide YY product is approved anywhere, and the hormone itself is classed as investigational in drug databases. Identity is settled: UniProtKB P10082, a 97-residue precursor, with peptide YY annotated at residues 29 to 64 and peptide YY(3-36) at 31 to 64, and an amidated tyrosine at position 64. FDA substance records exist for both forms, UNII T2670C12I5 with CAS 118997-30-1 for peptide YY and UNII 7PQZ90ULIR with CAS 123583-37-9 for the 3-36 form. Development history runs through a completed phase 2 nasal spray trial, NCT00537420, with 551 subjects in 2007 and 2008, and then through engineered analogs rather than the hormone: Novo Nordisk's NNC0165-1875 reached a phase 2 trial, NCT04969939, with 120 subjects and results posted in January 2026. This site's PYY1875 page covers that analog; it added little weight loss on top of semaglutide and was dropped.
You can compare this against the whole library, or read how to check a seller.
What else is like Peptide YY?
Others in Fat loss without GLP-1, side by side.If you're weighing Peptide YY, it's worth reading PYY1875 (NNC0165-1875), Spexin, and 5-Amino-1MQ in the same class.
A hormone whose effect survives replication in people and keeps failing to become a medicine.
- Dose
- No established dose
- How often
- Not applicable
A long-acting copy of the gut fullness hormone PYY that Novo Nordisk tested on top of semaglutide. It added 2.15 points of weight loss with frequent nausea, and development ended in 2023.
- Dose
- 1.0 mg once weekly, added to semaglutide 2.4 mg (phase 2 trial)
- How often
- Once weekly (phase 2 trial)
An appetite peptide found by computer search, still almost entirely in animals.
- Dose
- Research only
- How often
- Not established
A capsule studied for speeding up metabolism and burning fat.
- Dose
- 2.5 up to 5 mg per day injected (the capsule dose is far higher, see below)
- How often
- Daily, cycled
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- Batterham and colleagues, New England Journal of Medicine(2003)Inhibition of Food Intake in Obese Subjects by Peptide YY 3-36. Volume 349, issue 10, pages 941 to 948, September 2003. A double-blind, placebo-controlled crossover study in 12 obese and 12 lean subjects. Caloric intake at a buffet lunch two hours after infusion fell 30 percent in obese subjects and 31 percent in lean subjects, both P less than 0.001, so the effect was essentially identical in the two groups. Cumulative 24-hour intake also fell in both groups and plasma ghrelin was reduced. Fasting and postprandial endogenous peptide YY was lower in obese subjects, 10.2 plus or minus 0.7 against 16.9 plus or minus 0.8 pmol per liter, P less than 0.001, and endogenous levels correlated negatively with body mass index at r of minus 0.84. The authors conclude that obese subjects are not resistant to the effect and that peptide YY deficiency may contribute to obesity.
- Batterham and colleagues, Nature(2002)Gut hormone PYY3-36 physiologically inhibits food intake. Volume 418, issue 6898, pages 650 to 654. The earlier human work, reporting that infusion reduces food intake by 33 percent over 24 hours. The same paper's mouse work found the effect absent in animals lacking the Y2 receptor, and that is the genetic evidence that Y2 carries it.
- Tschoep and colleagues, Nature(2004)Does gut hormone PYY3-36 decrease food intake in rodents? Volume 430, issue 6996, pages 1 to 3, July 8, 2004, with 42 authors across many laboratories, reporting that they had been unable to replicate the rodent food-intake result. The title states the scope: the question was about rodents. A reply from the original authors ran in the same issue. An erratum followed on September 22, 2004, DOI 10.1038/nature03019, and it is a correction notice rather than a retraction. Nothing in the record retracts either paper.
- UniProtKB P10082, peptide YY precursor(2026)A 97-residue precursor. Annotates peptide YY at residues 29 to 64 and peptide YY(3-36) at residues 31 to 64, with a tyrosine amide at position 64 so both mature forms are C-terminally amidated, and a phosphoserine at 41. Read positionally, 29 to 64 gives YPIKPEAPREDASPEELNRYYASLRHYLNLVTRQRY and 31 to 64 gives IKPEAPREDASPEELNRYYASLRHYLNLVTRQRY. Also annotates a natural variant at precursor position 37, arginine to glycine, dbSNP rs229969. Records the receptor function, with the 3-36 form as the Y2 agonist.
Beyond these, 397 records are indexed. Browse the records