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Semaglutide vs Tirzepatide — GLP-1 Peptide Comparison
Semaglutide and Tirzepatide are the two most clinically significant metabolic peptides of the past decade. Both are FDA-approved and backed by large-scale Phase 3 trials. Tirzepatide is newer and shows greater average weight loss, but semaglutide has a longer track record and broader approval history.
| Semaglutide | Tirzepatide | |
|---|---|---|
| Mechanism | GLP-1 receptor agonist (single agonist) | Dual GLP-1 + GIP receptor agonist |
| Brand Names | Ozempic (diabetes), Wegovy (obesity), Rybelsus (oral) | Mounjaro (diabetes), Zepbound (obesity) |
| FDA Approval | Diabetes: 2017. Obesity (Wegovy): 2021 | Diabetes: 2022. Obesity (Zepbound): 2023 |
| Average Weight Loss | 10–15% body weight (Wegovy trials) | 15–22% body weight (Zepbound/SURMOUNT trials) |
| Head-to-Head Data | SURMOUNT-5 (2025, NEJM): Tirzepatide superior | Same trial — ~47% more weight loss than semaglutide at 72 weeks |
| GI Side Effects | Nausea, vomiting, diarrhea — common, usually transient | Similar profile — some evidence of fewer GI side effects at higher doses |
| Dosing | Once weekly subcutaneous (or daily oral for Rybelsus) | Once weekly subcutaneous injection |
| Blood Sugar Control | Reduces HbA1c 1–2% | Reduces HbA1c 2–2.5% (stronger glucose control) |
| Cardiovascular Data | SUSTAIN-6, SELECT trials — significant CV risk reduction | SURPASS-CVOT — cardiovascular outcomes trial ongoing |
| Research Status | Most studied GLP-1 agonist — extensive long-term data | Newer — strong Phase 3 data, long-term data still accumulating |
Bottom Line
Tirzepatide produces greater average weight loss and better blood sugar control in head-to-head data. Semaglutide has a longer track record, broader approval history, and more long-term safety data. Both are prescription medications — neither is available as a research peptide in the same category as BPC-157 or TB-500.
For educational and research purposes only. Not medical advice.