Semaglutide vs Tirzepatide
The two leading GLP-1 medications compared head to head
Semaglutide
GLP-1 receptor agonistTirzepatide
Dual GIP/GLP-1 receptor agonistHow They Work
Semaglutide
Mimics the GLP-1 hormone to reduce appetite and slow gastric emptying.
Tirzepatide
Activates both GIP and GLP-1 receptors, affecting appetite, insulin secretion, and fat metabolism.
Weight Loss Efficacy
STEP 1 trial: 14.9% weight loss vs 2.4% with placebo at 68 weeks (n=1,961)
SURMOUNT-1 trial: 22.5% weight loss (15 mg) vs 3.1% with placebo at 72 weeks (n=2,539)
Side Effects
Semaglutide
- Nausea (44%)
- Diarrhea (30%)
- Vomiting (24%)
- Constipation (24%)
- Abdominal pain (20%)
Tirzepatide
- Nausea (33%)
- Diarrhea (25%)
- Vomiting (17%)
- Constipation (20%)
- Injection site reactions (7%)
Cost Comparison
| Semaglutide | Tirzepatide | |
|---|---|---|
| Without Insurance | $1,300-$1,400/month (Wegovy) | $1,000-$1,100/month (Zepbound) |
| With Insurance | $0-$25/month with qualifying commercial insurance | $0-$25/month with qualifying commercial insurance |
| Compounded | $200-$500/month | $250-$550/month |
Pros & Cons
Semaglutide
Advantages
- Longer track record of clinical use
- More published long-term safety data
- Available in oral form (Rybelsus) for diabetes
- Widely covered by insurance for weight loss (Wegovy)
Considerations
- Slightly less weight loss than tirzepatide in head-to-head trials
- Single-hormone mechanism (GLP-1 only)
- Common GI side effects during dose escalation
Tirzepatide
Advantages
- Greater average weight loss in clinical trials
- Dual-hormone mechanism may improve metabolic outcomes
- Slightly lower nausea rates than semaglutide
- Lower list price than Wegovy
Considerations
- Newer medication with less long-term safety data
- Insurance coverage still catching up (especially for Zepbound)
- No oral formulation available
- Compounded versions face FDA scrutiny
The Bottom Line
Both are highly effective for weight loss. Tirzepatide shows greater average weight loss in trials (20-22% vs 15-17%), but semaglutide has a longer safety track record and broader insurance coverage. Your provider will consider your medical history, insurance, and treatment goals when recommending one over the other.
Frequently Asked Questions
In head-to-head clinical trials, tirzepatide produced greater average weight loss. However, "better" depends on your individual response, insurance coverage, side effect profile, and medical history. Both are effective options.
Yes, switching is possible under medical supervision. Your doctor will typically start you at a lower dose of the new medication and adjust gradually. Do not switch medications without consulting your provider.
Both have similar gastrointestinal side effects (nausea, diarrhea, constipation). Tirzepatide may have slightly lower nausea rates based on trial data, but individual responses vary significantly.
Compounded medications are not FDA-approved. Quality depends entirely on the compounding pharmacy. Look for PCAB-accredited or state-licensed 503B pharmacies. Discuss compounded options with your doctor.
Medical Disclaimer: This comparison is for informational purposes only and is not medical advice. All clinical data is sourced from FDA prescribing information and published peer-reviewed trials. Individual results vary. Always consult a qualified healthcare provider before starting, stopping, or switching any medication.