Head-to-head comparison
| Property | Semaglutide | Tirzepatide |
|---|---|---|
| Category | Weight Loss | Weight Loss |
| Legal Status | Prescription | Prescription |
| Primary Route | subcutaneous | subcutaneous |
| Half-life | ~7 days | ~5 days |
| Mol. Weight | 4,113.58 Da | 4,813.45 Da |
| Side Effects | Nausea (39%), Vomiting, Diarrhea | Nausea (up to 31%), Diarrhea, Vomiting |
Key differences
- Receptor targets: Semaglutide is a GLP-1 receptor agonist only; tirzepatide is a dual GIP/GLP-1 receptor agonist.
- Weight loss efficacy: SURMOUNT trials showed tirzepatide (15 mg) achieved 22.5% weight loss over 72 weeks; STEP trials showed semaglutide (2.4 mg) achieved 15–17% weight loss over 68 weeks.
- Manufacturer: Semaglutide is made by Novo Nordisk (Ozempic, Wegovy); tirzepatide is made by Eli Lilly (Mounjaro, Zepbound).
- Half-life: Semaglutide has a half-life of approximately 7 days; tirzepatide has a half-life of approximately 5 days. Both support weekly dosing.
- Dosing range: Semaglutide titrates from 0.25 mg to 2.4 mg weekly; tirzepatide titrates from 2.5 mg to 15 mg weekly.
- GI side effects: Both cause nausea, vomiting, and diarrhea; semaglutide has a reported nausea rate of about 39% vs tirzepatide at about 31% in trials.
- Track record: Semaglutide has a longer market presence (FDA-approved 2017 for diabetes, 2021 for obesity) and more published cardiovascular outcomes data; tirzepatide was FDA-approved in 2022 (diabetes) and 2023 (obesity).
The verdict
Head-to-head trial data shows tirzepatide produces greater weight loss than semaglutide, likely due to the additional GIP receptor activation. However, semaglutide has a longer track record, more published safety and cardiovascular outcomes data, and broader clinical experience. Cost, insurance coverage, and supply availability also differ. The choice is best made with a prescribing physician based on individual health profile, treatment goals, and access considerations.
Frequently asked questions
In clinical trials, tirzepatide (15 mg) produced approximately 22.5% body weight reduction over 72 weeks, compared to 15–17% with semaglutide (2.4 mg) over 68 weeks. Head-to-head studies confirm tirzepatide's superiority for weight loss at maximum doses.
Switching between GLP-1 medications should be done under medical supervision. Physicians typically manage the transition by stopping one medication and starting the other at the initial titration dose. There is no standardized dose-equivalence conversion between semaglutide and tirzepatide.
Both have similar GI side effect profiles (nausea, vomiting, diarrhea). Trial data shows semaglutide has a slightly higher nausea rate (about 39%) compared to tirzepatide (about 31%). Individual tolerance varies significantly, and side effects typically improve after the titration period.
List prices are comparable for both medications (roughly $1,000–$1,400/month without insurance as of 2026). Actual cost depends on insurance formulary placement, manufacturer savings programs, and pharmacy. Compounded versions have been available at lower cost but face regulatory action.
Semaglutide activates only the GLP-1 receptor. Tirzepatide activates both the GIP and GLP-1 receptors simultaneously. GIP receptor activation is thought to enhance insulin sensitivity and improve fat metabolism beyond what GLP-1 alone achieves, producing the observed superior weight loss.
Semaglutide has published cardiovascular outcomes data (SELECT trial) showing reduced risk of major cardiovascular events. Tirzepatide cardiovascular outcomes trials are ongoing with preliminary results expected. Both are being studied for NASH, Alzheimer's, and other conditions beyond diabetes and obesity.
Discussion (0)
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