Peptide YY
Evidence: B/C — Meaningful Human EvidenceGastrointestinal / Gut-Hormone Signaling
Evidence Snapshot
What this grade covers
This grade is concentrated in PYY(3-36)-specific evidence, and specifically in the IV-infusion route (Batterham 2002, PMID 12167864; Sloth 2007 IV study, PMID 17148749; Witte 2009, PMID 19651163) -- Evidence Grade B. PYY(1-36)'s own human efficacy evidence is materially weaker and graded separately at C: it showed no significant effect on energy intake in either the IV-infusion study (PMID 17148749) or the subcutaneous-injection study (PMID 17566112). PYY(3-36)'s IV-route efficacy finding also carries a major tolerability caveat -- at the effective infusion dose used by Sloth et al. (2007), only 4 of the originally enrolled participants completed dosing because of nausea (PMID 17148749), and a separate study (PMID 18275682) confirms nausea at supraphysiological IV doses without added benefit. Subcutaneous PYY(3-36) dosing (PMID 17566112) did not reproduce a significant energy-intake effect at all, though it did show dose-dependent satiety/hunger-rating improvement. This grade should not be read as applying equally, or without qualification, to PYY(1-36) or to every administration route.
Regulatory Context
No PYY-based drug product is FDA-approved for any indication as of this review. All evidence summarized here comes from investigational human research studies, not from an approved medicine.
Research Takeaway
PYY(1-36) and PYY(3-36) are distinct circulating forms of Peptide YY with different receptor activity; PYY(3-36) is a selective Y2-receptor agonist and is the form responsible for most of the documented human appetite-suppression evidence.
Evidence boundary: Do not treat PYY(3-36) as an unrestricted synonym for 'PYY' generally.
See all 5 evidence claims →Quick Summary
Peptide YY (PYY) is a gut hormone released after eating. Human research distinguishes two forms: PYY(3-36), which has been shown in controlled intravenous-infusion studies to reduce appetite and food intake (though at a dose that caused nausea in a majority of one study's participants), and PYY(1-36), which has not shown the same food-intake effect. PYY is related to, but functionally distinct from, Neuropeptide Y (NPY), which is covered separately on this site.
Mechanism & Research Overview
Peptide YY (PYY) is a gut hormone released after eating. Human research distinguishes two forms: PYY(3-36), which has been shown in controlled intravenous-infusion studies to reduce appetite and food intake (though at a dose that caused nausea in a majority of one study's participants), and PYY(1-36), which has not shown the same food-intake effect. PYY is related to, but functionally distinct from, Neuropeptide Y (NPY), which is covered separately on this site.
Evidence Claims
Individual scientific statements drawn from the sources cited below, each shown with the specific evidence boundary that statement does not establish.
Supported
PYY(1-36) and PYY(3-36) are distinct circulating forms of Peptide YY with different receptor activity; PYY(3-36) is a selective Y2-receptor agonist and is the form responsible for most of the documented human appetite-suppression evidence.
Does not establish
Evidence boundary: Do not treat PYY(3-36) as an unrestricted synonym for 'PYY' generally.
Supported
Intravenous infusion of PYY(3-36) at postprandial-range concentrations significantly reduces appetite and food intake in healthy human volunteers.
Does not establish
Evidence boundary: Demonstrated via acute IV infusion in small controlled studies; the effective IV dose used in a key replication/form-comparison study caused nausea severe enough that only 4 of the planned participants completed dosing (PMID 17148749) -- this tolerability limitation must accompany the efficacy claim.
Sources: Gut Hormone PYY3-36 Physiologically Inhibits Food Intake; Effects of PYY1-36 and PYY3-36 on Appetite, Energy Intake, Energy Expenditure, Glucose and Fat Metabolism in Obese and Lean Subjects
Supported
PYY(1-36) has not been shown in controlled human studies to significantly reduce ad-libitum energy intake, whether given by intravenous infusion or subcutaneous injection.
Does not establish
Evidence boundary: Absence of an established efficacy signal is not the same as proof of no effect. Do not use PYY(3-36)'s efficacy data to imply PYY(1-36) shares it.
Sources: Effects of PYY1-36 and PYY3-36 on Appetite, Energy Intake, Energy Expenditure, Glucose and Fat Metabolism in Obese and Lean Subjects; Effect of Subcutaneous Injections of PYY1-36 and PYY3-36 on Appetite, Ad Libitum Energy Intake, and Plasma Free Fatty Acid Concentration in Obese Males
Supported
Both PYY(1-36) and PYY(3-36) slow gastric emptying in humans, with PYY(3-36) producing a larger effect.
Does not establish
Evidence boundary: A gastric-motility mechanism finding; does not by itself establish a weight-management outcome.
Sources: Differential Effect of PYY1-36 and PYY3-36 on Gastric Emptying in Man
Supported
Neuropeptide Y (NPY) is a structurally related but functionally distinct hormone from Peptide YY. NPY evidence must not be cited as PYY evidence, and vice versa.
Does not establish
Evidence boundary: Firewall statement. No peptide-neuropeptide-y study may be reused here.
Safety & Evidence Limitations
Considerations reported in the sources cited on this page — not a complete list of every possible risk, and not medical advice.
Safety Consideration
At the effective IV infusion dose used in the key form-comparison study, only 4 of the originally enrolled participants completed PYY3-36 dosing because of nausea (PMID 17148749); a separate study confirms nausea at supraphysiological IV doses with no added appetite benefit (PMID 18275682).Safety Consideration
Subcutaneous PYY1-36/PYY3-36 dosing over 5 days did not significantly reduce ad-libitum energy intake in obese men, despite improving subjective satiety/hunger ratings for PYY3-36 (PMID 17566112).Safety Consideration
Two controlled human studies (IV and subcutaneous) both found no significant PYY1-36 effect on energy intake.Safety Consideration
All controlled human PYY studies located in this review involve small cohorts (single digits to ~24 participants) and short (acute to 5-day) exposure -- no long-term human PYY administration RCT was identified.
Research Areas Being Studied
Research areas discussed on this page reflect the Gastrointestinal / Gut-Hormone Signaling category and the sources cited below.
Findings Reported in Studies
Educational summary only — reported in cited studies, not a claim of proven benefit.
- Differential Effect of PYY1-36 and PYY3-36 on Gastric Emptying in Man (2009):
- Supraphysiological Doses of Intravenous PYY3-36 Cause Nausea, but No Additional Reduction in Food Intake (2008):
- Effect of Subcutaneous Injections of PYY1-36 and PYY3-36 on Appetite, Ad Libitum Energy Intake, and Plasma Free Fatty Acid Concentration in Obese Males (2007):
- Effects of PYY1-36 and PYY3-36 on Appetite, Energy Intake, Energy Expenditure, Glucose and Fat Metabolism in Obese and Lean Subjects (2007):
- Gut Hormone PYY3-36 Physiologically Inhibits Food Intake (2002):
Study Tables by Evidence Type
Human Studies & Clinical Data
| Title | Year | Population / Model | Dose / Duration / Finding | Safety Notes | Source |
|---|---|---|---|---|---|
| Differential Effect of PYY1-36 and PYY3-36 on Gastric Emptying in Man | 2009 | Both native PYY forms slowed gastric emptying in humans; PYY(3-36) was more effective (half-emptying time prolonged from 63.1 to 87.0 minutes vs. saline). | |||
| Supraphysiological Doses of Intravenous PYY3-36 Cause Nausea, but No Additional Reduction in Food Intake | 2008 | 6 volunteers | Supraphysiological IV PYY(3-36) doses caused nausea in 5 of 6 subjects with no additional food-intake reduction vs. physiological dosing. | Genuine negative/dose-ceiling finding -- higher doses do not give better appetite suppression. | |
| Effect of Subcutaneous Injections of PYY1-36 and PYY3-36 on Appetite, Ad Libitum Energy Intake, and Plasma Free Fatty Acid Concentration in Obese Males | 2007 | 24 obese men, no lean arm | Escalating subcutaneous doses of both PYY forms over 5 days: neither form significantly changed ad-libitum energy intake; PYY(3-36) produced dose-dependent improvements in satiety/hunger ratings and raised FFA; PYY(1-36) showed neither effect. | A genuine route/form-dependent null finding for energy intake, distinct from the positive IV-infusion result in PMID 17148749 -- must not be conflated with it. | |
| Effects of PYY1-36 and PYY3-36 on Appetite, Energy Intake, Energy Expenditure, Glucose and Fat Metabolism in Obese and Lean Subjects | 2007 | 12 lean + 12 obese men, blinded randomized crossover | 90-minute IV infusions (0.8 pmol/kg/min) of both native PYY forms: PYY(3-36) reduced energy intake, lowered well-being ratings, and raised FFA/glucose/insulin/heart rate/energy expenditure; PYY(1-36) had no effect on energy intake. | Only 4 of the originally enrolled participants completed the PYY(3-36) arm at this dose because of nausea -- a major tolerability/attrition finding that must accompany any efficacy statement. | |
| Gut Hormone PYY3-36 Physiologically Inhibits Food Intake | 2002 | IV infusion of PYY(3-36) at postprandial-range concentrations significantly decreased appetite and reduced 24-hour food intake by 33% vs. saline in human volunteers. | PYY(3-36)-form-scoped; must not be generalized to PYY(1-36). |
Animal / Cell / Preclinical Data
No Animal / Cell / Preclinical Data Listed Yet
This section will be updated as sources are added.
Regulatory Documents & Official Trial Registries
No Regulatory Documents & Official Trial Registries Listed Yet
This section will be updated as sources are added.
Anecdotal Reported Patterns — Not Medical Advice
Anecdotal Reported Patterns — Not Medical Advice
Reported dosing patterns are included for educational context only. They are self-reported, unverified, not medical advice, and not instructions for human use. Community-submitted patterns are not yet available in this Phase 1 prototype; this section is a placeholder reserved for moderated, aggregated community data.
Lab Markers to Discuss With a Clinician
Educational topics only — not self-monitoring instructions.
FAQ
Disclaimer
Educational information only. This page summarizes published human research on Peptide YY and does not constitute medical advice, a treatment recommendation, or dosing guidance for any PYY-related substance.
Educational use only. This content is provided for informational and research-summary purposes only. It is not medical advice, not a treatment recommendation, not a dosing guide, and not a substitute for care from a licensed medical professional. Nothing here is intended to diagnose, treat, cure, prevent, or mitigate disease. Reported dosing patterns, when shown elsewhere on the site, must be labeled either as Study / Trial Dosing or Anecdotal Reported Patterns — Not Medical Advice. Community reports are self-reported, unverified, and not scientific proof.
Community-reported experiences, once enabled, must be displayed only as moderated, anonymized, or aggregated data. They are anecdotal, self-reported, unverified, and should never be presented as proof of safety, efficacy, or expected results.
Content status: Published. Last updated 2026-08-26.
Follow research updates for Peptide YY
Get notified in your MitoCore account when this profile is updated, a new study is added, or its evidence grade changes.
Get updates when new studies or safety notes are added for this peptide.
Get educational updates on new studies, evidence-grade changes, and safety notes. Educational content only — not medical advice.