Head to head
Peptide YY against Semaglutide
Two different satiety signals, one a gut hormone released after eating and one a drug class built on a different gut hormone. PYY has been repeatedly pursued as a drug target and repeatedly limited by nausea, which is context worth having before reading any claim about it.
Column A
Peptide YYPeptide YY (PYY, including the circulating fragment PYY3-36)
A gut hormone released after meals alongside GLP-1. Infused into 12 lean and 12 obese people it cut buffet intake by about 30 percent in both, but the rodent finding it was built on failed a published multi-laboratory replication, and nausea kept it from becoming a drug.
Column B
SemaglutideSemaglutide (GLP-1 receptor agonist)
A long-acting GLP-1 receptor agonist approved for type 2 diabetes and chronic weight management, with proven cardiovascular risk reduction.
Side by side, on the facts we can check
| Attribute | Peptide YY | Semaglutide |
|---|---|---|
| Category | Metabolic | Metabolic |
| FDA status | Not FDA-approved. No PYY or PYY3-36 product is approved anywhere; native PYY3-36 has been studied in people only by intravenous or subcutaneous infusion. | FDA-approved (Ozempic, Rybelsus for T2D; Wegovy injection, Wegovy pill approved Dec 2025, and Wegovy HD 7.2 mg approved Mar 2026 for weight management) |
| Half-life | Not reported | ~7 days |
| Molecular weight | 11,145 Da precursor (97 residues, UniProt P10082); PYY(1-36) is residues 29 to 64 and PYY(3-36) residues 31 to 64 | 4,113.6 Da |
| Mechanism | Established in humans by infusion: PYY3-36 at postprandial concentrations reduces appetite ratings and ad libitum energy intake for hours, lowers plasma ghrelin, and does so equally in lean and obese people. Established in rodents but contested (see the dispute): peripheral PYY3-36 reduces food intake through the Y2 receptor, an effect absent in Y2 receptor knockout mice, with increased c-Fos in the arcuate nucleus, reduced hypothalamic NPY mRNA and inhibition of NPY neuron firing that disinhibits adjacent POMC neurons. PYY(1-36) is relatively non-selective across Y1, Y2 and Y5 receptors; DPP-4 cleavage to PYY3-36 confers Y2 preference. PYY also slows gastric emptying and intestinal transit, the older ileal brake function. | Activates the GLP-1 receptor, increasing insulin secretion when glucose is elevated, suppressing glucagon, slowing gastric emptying, and acting on hypothalamic appetite centers to reduce food intake. |
| Human studies cited | 3 | 5 |
| Legal status, US | Not approved; research use only | FDA-approved, prescription only |
Frequently asked questions
What is the difference between Peptide YY and Semaglutide?
Peptide YY: A gut hormone released after meals alongside GLP-1. Infused into 12 lean and 12 obese people it cut buffet intake by about 30 percent in both, but the rodent finding it was built on failed a published multi-laboratory replication, and nausea kept it from becoming a drug. Semaglutide: A long-acting GLP-1 receptor agonist approved for type 2 diabetes and chronic weight management, with proven cardiovascular risk reduction.
Which has stronger research evidence, Peptide YY or Semaglutide?
This database does not grade compounds. It counts what was run in people: 3 of the 8 studies cited on the Peptide YY profile were human work, against 5 of 5 for Semaglutide. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Peptide YY and Semaglutide FDA-approved?
Peptide YY: Not FDA-approved. No PYY or PYY3-36 product is approved anywhere; native PYY3-36 has been studied in people only by intravenous or subcutaneous infusion.. Semaglutide: FDA-approved (Ozempic, Rybelsus for T2D; Wegovy injection, Wegovy pill approved Dec 2025, and Wegovy HD 7.2 mg approved Mar 2026 for weight management).
Related posts
Blog articles that cover Peptide YY or Semaglutide, newest first.
- Dispatch / Sep 12, 2026 / 8 minDispatch 001: Five Retatrutide Phase 3 Trials Have Finished And None Has Posted Results
- Metabolic / Sep 8, 2026 / 8 minTesofensine Is Not a Peptide: What It Is, the Trials, and the Heart-Rate Issue
- Longevity / Sep 8, 2026 / 12 minPeptides for Longevity: What the Evidence Actually Shows in 2026
- Metabolic / Sep 8, 2026 / 10 minOral GLP-1s in 2026: Wegovy Pill vs Foundayo (Orforglipron) vs Rybelsus, and What Is Coming
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.