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All peptides
GastrointestinalIn Clinical Trials

Peptide YY (PYY 3-36)

Intravenous, Intranasal
Written by Peptide Association Editorial TeamMedically reviewed by Ian Justl Ellis, MD, CPTLast reviewed Editorial policy

Overview

Peptide YY 3-36 is a 34-amino acid endogenous peptide hormone secreted by L-cells in the distal small intestine and colon in response to nutrient intake. It acts primarily on the Y2 receptor in the hypothalamus to reduce appetite and slow gastric emptying, functioning as part of the ileal brake mechanism.

Mechanism of Action

The therapeutic rationale for exogenous PYY 3-36 administration centers on treatment of obesity through appetite suppression. Circulating levels are reduced in obesity and elevated after bariatric surgery.

Research Summary & Key Findings

Early proof-of-concept studies demonstrated that intravenous PYY 3-36 infusion reduced food intake in both lean and obese subjects. Clinical development of intranasal formulations has been pursued to improve delivery, but phase II trials showed modest weight loss and challenges with patient adherence and tolerability. No PYY-based therapeutic has advanced beyond mid-stage trials, though interest persists in combination approaches with other gut hormones.

Clinical Status

In Clinical Trials

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.

Administration Routes

IntravenousIntranasal

References

Primary literature

Study-level citations for this compound are being verified against the primary sources before publication. The database queries above return the current indexed literature in the meantime.

Related Peptides in Gastrointestinal

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 there is nothing for us to sell you here and no consultation to book. That can change: eight peptides moved back to a lawful pathway in February 2026.

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One email, only if this compound's regulatory standing actually moves. Not a newsletter, not a sales sequence.

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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.