Semaglutide and tirzepatide are the two dominant GLP-1 medications on the market, but they work differently, produce different results, and come at different price points. If you're deciding between the two, here's what the clinical evidence actually shows.
How They Work: The Mechanism Difference
Semaglutide is a GLP-1 receptor agonist — it mimics the GLP-1 hormone that your gut releases after eating. This slows gastric emptying, reduces appetite, and improves insulin sensitivity.
Tirzepatide is a dual GIP/GLP-1 receptor agonist. In addition to activating the GLP-1 receptor, it also activates the GIP (glucose-dependent insulinotropic polypeptide) receptor. This dual mechanism appears to produce greater effects on both weight loss and blood sugar control.
Think of it this way: semaglutide activates one pathway. Tirzepatide activates two. The clinical results reflect this difference.
Weight Loss: Head-to-Head Results
| Metric | Semaglutide 2.4mg (STEP-1) | Tirzepatide 15mg (SURMOUNT-1) |
|---|---|---|
| Average weight loss | ~14.9% | ~20.9% |
| Trial duration | 68 weeks | 72 weeks |
| Patients losing ≥20% body weight | ~32% | ~57% |
| Patients losing ≥5% body weight | ~86% | ~91% |
Tirzepatide produces greater average weight loss at the highest approved doses. However, semaglutide still delivers clinically meaningful results for most patients, and some patients respond better to semaglutide than to tirzepatide — individual variation matters.
Blood Sugar Control
Both medications are approved for type 2 diabetes. Tirzepatide achieved superior A1C reductions in the SURPASS trials compared to semaglutide in SUSTAIN trials, though direct head-to-head diabetes data is limited. Both medications reduce A1C by approximately 1.5–2.0 percentage points at therapeutic doses.
Cardiovascular Benefits
Semaglutide has the strongest cardiovascular evidence. The SELECT trial demonstrated a 20% reduction in major adverse cardiovascular events (heart attack, stroke, cardiovascular death) in patients with obesity and established cardiovascular disease — even without diabetes. This data led to Wegovy's FDA approval for cardiovascular risk reduction.
Tirzepatide's cardiovascular outcomes trial (SURPASS-CVOT) is still reporting, so the full picture isn't available yet. Early data is encouraging, but semaglutide currently has the evidence edge for heart health.
Side Effects Comparison
| Side Effect | Semaglutide | Tirzepatide |
|---|---|---|
| Nausea | ~44% | ~24–33% |
| Diarrhea | ~30% | ~18–22% |
| Vomiting | ~24% | ~9–13% |
| Constipation | ~24% | ~17–23% |
| Discontinuation due to GI side effects | ~7% | ~4–7% |
Tirzepatide tends to produce fewer gastrointestinal side effects than semaglutide at comparable efficacy levels. This is one of its practical advantages — patients who struggle with semaglutide's GI profile may tolerate tirzepatide better.
Pricing: Brand-Name vs Compounded
| Format | Semaglutide | Tirzepatide |
|---|---|---|
| Brand-name (retail) | Wegovy: ~$1,349/mo | Zepbound: ~$1,060/mo |
| Brand-name oral | Oral Wegovy: $149/mo (NovoCare promo) | Not available |
| Compounded (typical range) | $130–$300/mo | $149–$350/mo |
Compounded semaglutide is generally cheaper than compounded tirzepatide. Brand-name oral Wegovy at $149/mo through NovoCare (promo through August 2026) currently offers the lowest brand-name entry point.
Available Formats
Semaglutide is available as a weekly injection (Ozempic, Wegovy), a daily oral tablet (Rybelsus, oral Wegovy), and in compounded formulations including injectable, sublingual, and tablet forms.
Tirzepatide is currently available only as a weekly injection (Mounjaro, Zepbound) and in compounded injectable form. Oral tirzepatide is in clinical development but not yet available.
Which Should You Choose?
There's no universal answer, but the data suggests some practical guidelines:
- Maximize weight loss: Tirzepatide produces greater average weight loss at comparable doses
- Cardiovascular protection: Semaglutide has the proven CV outcomes data (SELECT trial)
- Minimize GI side effects: Tirzepatide tends to produce fewer nausea and vomiting episodes
- Lowest cost: Compounded semaglutide, or brand-name oral Wegovy at $149/mo promo pricing
- Non-injection option: Semaglutide (oral formats available); tirzepatide is injection-only currently
- Type 2 diabetes + weight loss: Either medication works; tirzepatide may offer modestly better glucose control
Your prescribing provider can help determine which medication fits your clinical profile. Many telehealth platforms offer both options.
Compare providers offering both semaglutide and tirzepatide
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- Wilding JPH, et al. "Once-weekly semaglutide in adults with overweight or obesity." STEP-1 trial. N Engl J Med. 2021;384:989–1002.
- Jastreboff AM, et al. "Tirzepatide once weekly for the treatment of obesity." SURMOUNT-1 trial. N Engl J Med. 2022;387:205–216.
- Lincoff AM, et al. "Semaglutide and cardiovascular outcomes in obesity without diabetes." SELECT trial. N Engl J Med. 2023;389:2221–2232.
- FDA prescribing information for Wegovy (semaglutide 2.4mg injection), Zepbound (tirzepatide injection), and oral semaglutide.
- Novo Nordisk NovoCare: oral Wegovy promotional pricing ($149/mo for 1.5mg and 4mg) through August 2026.
- SURPASS clinical trial program: tirzepatide diabetes efficacy and safety data.
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