Semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) are the two dominant GLP-1 receptor agonists on the market. Both produce significant weight loss and cardiometabolic improvements—but they work differently, and the clinical data that has accumulated through 2026 reveals some important distinctions.
The Fundamentals
| Feature | Semaglutide | Tirzepatide |
|---|---|---|
| Mechanism | GLP-1 receptor agonist (single) | GLP-1 + GIP dual agonist |
| Brand Names (Diabetes) | Ozempic | Mounjaro |
| Brand Names (Weight Loss) | Wegovy, Wegovy HD (7.2mg) | Zepbound |
| Manufacturer | Novo Nordisk | Eli Lilly |
| Administration | Weekly injection (oral also available) | Weekly injection |
| Dose Range (Weight Loss) | 0.25mg – 7.2mg weekly | 2.5mg – 15mg weekly |
| Half-Life | ~7 days | ~5 days |
Weight Loss: The Numbers
This is where most patients start their comparison, and the data is now robust enough to draw clear conclusions.
Semaglutide
- STEP 1 trial (2.4mg): 14.9% average weight loss at 68 weeks
- Wegovy HD (7.2mg): 20.7% average weight loss (FDA approved 2025/2026)
- STEP 5 (2-year data): 15.2% sustained weight loss at 104 weeks
Tirzepatide
- SURMOUNT-1 (15mg): 22.5% average weight loss at 72 weeks
- SURMOUNT-2 (diabetes patients): 14.7% average weight loss at 72 weeks
- Some participants: Over 25% weight loss at the highest dose in SURMOUNT-1
The Takeaway on Weight Loss
At maximum doses, tirzepatide produces about 5–7 percentage points more weight loss than standard-dose semaglutide (2.4mg). However, the new Wegovy HD 7.2mg formulation narrows this gap significantly, showing 20.7% weight loss—approaching tirzepatide territory.
Beyond Weight Loss: Approved Indications
Both medications have expanded well beyond their original diabetes and weight loss approvals.
Semaglutide Additional Indications
- Cardiovascular risk reduction: SELECT trial showed 20% reduction in major cardiovascular events
- MASH/fatty liver disease: Wegovy approved for MASH treatment
- Chronic kidney disease: FLOW trial stopped early for efficacy
- Heart failure (HFpEF): FDA-approved indication
- Peripheral artery disease (PAD): FDA-approved indication
Tirzepatide Additional Indications
- Obstructive sleep apnea: Zepbound approved for moderate-to-severe OSA
- Heart failure (HFpEF): Under review / approved
- Cardiovascular outcomes: SURPASS-CVOT trial ongoing
As of early 2026, semaglutide has a wider range of proven indications beyond weight loss—particularly in cardiovascular and kidney disease. Tirzepatide’s cardiovascular outcomes trial is expected to report results in 2026–2027, which could change this picture.
Side Effects Comparison
Both medications share the same class of side effects—primarily gastrointestinal—but there are nuanced differences.
| Side Effect | Semaglutide | Tirzepatide |
|---|---|---|
| Nausea | ~44% | ~31% |
| Diarrhea | ~30% | ~23% |
| Vomiting | ~24% | ~13% |
| Constipation | ~24% | ~17% |
| Injection Site Reactions | ~4% | ~7% |
| Discontinuation Due to AEs | ~7% | ~7% |
Tirzepatide tends to produce slightly lower rates of nausea and vomiting compared to semaglutide at therapeutic doses. However, both medications have similar discontinuation rates due to side effects—around 7%—suggesting that most patients who experience side effects can tolerate them with proper management.
Cost Comparison (2026)
| Version | Semaglutide | Tirzepatide |
|---|---|---|
| Brand-Name (Cash Price) | $1,000–$1,600/month | $1,000–$1,200/month |
| Compounded (503A/503B) | $150–$350/month | $200–$450/month |
| With Insurance (avg copay) | $25–$250/month | $25–$250/month |
Compounded tirzepatide typically costs more than compounded semaglutide because the raw ingredient is more expensive. Both are dramatically cheaper than brand-name versions for patients paying out of pocket.
So Which One Should You Choose?
There’s no single right answer—it depends on your specific situation. Here’s a framework:
Tirzepatide May Be Better If…
- You need maximum weight loss (especially if BMI is 40+)
- You have type 2 diabetes (dual GIP/GLP-1 mechanism provides superior glucose control)
- You’ve tried semaglutide and plateaued
- You have obstructive sleep apnea
- You experience significant nausea on semaglutide
Semaglutide May Be Better If…
- You have cardiovascular risk factors (SELECT trial data is definitive)
- You have kidney disease (FLOW trial data)
- You prefer an oral option (Rybelsus / Wegovy pill)
- You have MASH/fatty liver disease
- Cost is a primary concern (compounded semaglutide is generally cheaper)
- You want the medication with the longest safety track record
Most Important
Either medication represents a massive leap forward from where obesity treatment was five years ago. The “wrong” choice between semaglutide and tirzepatide is still a very good choice. Work with your provider to pick the one that fits your medical profile, budget, and goals.
The Bottom Line
In 2026, tirzepatide leads on raw weight loss numbers and may have an edge for patients with diabetes or sleep apnea. Semaglutide leads on breadth of evidence, with proven cardiovascular, kidney, and liver benefits that tirzepatide hasn’t yet matched. Both are evolving rapidly—tirzepatide’s cardiovascular outcomes trial and semaglutide’s higher-dose formulations will continue to reshape this comparison.