Gastrointestinal · In Clinical Trials
Peptide YY (PYY 3-36)
No lawful US pathway
01 · Overview
Peptide YY 3-36 is a 34-amino acid fragment of the 36-amino acid gut hormone peptide YY, which is released from intestinal L-cells after meals in proportion to calorie intake (PMID 15960866). PYY3-36 acts on the Y2 receptor to inhibit hypothalamic neuropeptide Y neurons and reduce food intake (PMID 15960866), and it contributes to the ileal brake that slows upper gut transit.
The therapeutic rationale for exogenous PYY3-36 is appetite suppression in obesity. In one study, fasting and post-meal PYY levels were lower in obese than in lean subjects (PMID 12954742).
02 · Research summary & key findings
In a crossover study (NEJM 2003), intravenous PYY3-36 reduced buffet-meal calorie intake by about 30% in both 12 obese and 12 lean subjects (PMID 12954742). Another infusion study found that significant reductions in food intake occurred only at pharmacological plasma levels, with nausea as a common side effect (PMID 16285944). In a 12-week trial in 133 obese adults, intranasal PYY3-36 did not produce significant weight loss, and most patients on the higher dose discontinued because of nausea and vomiting (PMID 17341568). A 4-week subcutaneous infusion of PYY combined with GLP-1 and oxyntomodulin produced greater weight loss than saline in patients with obesity and dysglycemia (PMID 31177183).
03 · Regulatory status
Peptide YY (PYY 3-36) is currently undergoing clinical trials. It is not yet FDA-approved and is available only through clinical research settings or investigational protocols.
No lawful pathway today
Peptide YY (PYY 3-36) is not FDA-approved and does not currently have a lawful prescription or compounding pathway in the United States, so we do not sell it and will not book a consultation for it. That can change: in 2026 FDA began reviewing several peptides for compounding.
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04 · Administration routes
- Intravenous
- Intranasal
References
- [1]Inhibition of food intake in obese subjects by peptide YY3-36 N Engl J Med, 2003. PMID 12954742
- [2]Peptide YY, appetite and food intake Proc Nutr Soc, 2005. PMID 15960866
- [3]Effect of peptide YY3-36 on food intake in humans Gastroenterology, 2005. PMID 16285944
- [4]Efficacy and safety of intranasal peptide YY3-36 for weight reduction in obese adults J Clin Endocrinol Metab, 2007. PMID 17341568
- [5]Combined GLP-1, Oxyntomodulin, and Peptide YY Improves Body Weight and Glycemia in Obesity and Prediabetes/Type 2 Diabetes: A Randomized, Single-Blinded, Placebo-Controlled Study Diabetes Care, 2019. PMID 31177183
Primary literature
- PubMed: "Peptide YY"
Peer-reviewed literature indexed by the National Library of Medicine.
- ClinicalTrials.gov: "Peptide YY"
Registered interventional and observational studies, including status and phase.
- PubChem: "Peptide YY"
Chemical structure, molecular properties, and bioactivity data.
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Disclaimer: This information is provided for educational and research purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide therapy. The Peptide Association does not endorse or recommend any specific treatment protocol. See our editorial policy for how this content is produced and reviewed. Clinicians: join the network.