Semaglutide vs Tirzepatide
GLP-1 vs dual GIP/GLP-1 for weight and diabetes
The 30-second view
- ~15%
- ~20–22%
- Proven (SELECT)
- Trial ongoing
- Established
- Established
- Injection · weekly
- Injection · weekly
- FDA-approved
- FDA-approved
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| Weight loss | ~15% | ~20–22% |
| Cardiovascular outcomes | Proven (SELECT) | Trial ongoing |
| Evidence maturity | Established | Established |
| Route · dosing | Injection · weekly | Injection · weekly |
| Regulatory | FDA-approved | FDA-approved |
Overview
Both are once-weekly injectable incretin medications approved for weight management and type 2 diabetes. Tirzepatide adds GIP activity to the GLP-1 mechanism that semaglutide uses.
Quick summary
When each is appropriate
When proven cardiovascular-event reduction is a priority (semaglutide has outcome data), or based on access, coverage, and clinician judgment.
When maximal weight loss or glycemic reduction is the goal and cardiovascular-outcome proof is not the deciding factor.
Evidence comparison
- GLP-1 agonist
- GIP + GLP-1 agonist
- ~15% (STEP program)
- ~20–22% (SURMOUNT-1)
- Substantial
- Greater (SURPASS-2)
- Proven event reduction (SELECT)
- Outcome trial ongoing — not yet proven
- Established
- Established
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| Mechanism | GLP-1 agonist | GIP + GLP-1 agonist |
| Average weight loss (obesity) | ~15% (STEP program) | ~20–22% (SURMOUNT-1) |
| Head-to-head glycemic effect | Substantial | Greater (SURPASS-2) |
| Cardiovascular outcomes | Proven event reduction (SELECT) | Outcome trial ongoing — not yet proven |
| BioSignal evidence maturity | Established | Established |
Safety comparison
- GI (nausea, diarrhea)
- GI (nausea, diarrhea)
- Rodent thyroid C-cell signal
- Rodent thyroid C-cell signal
- Longer track record
- Shorter (newer agent)
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| Common effects | GI (nausea, diarrhea) | GI (nausea, diarrhea) |
| Boxed warning | Rodent thyroid C-cell signal | Rodent thyroid C-cell signal |
| Long-term data | Longer track record | Shorter (newer agent) |
Regulatory comparison
- Approved (Ozempic / Wegovy)
- Approved (Mounjaro / Zepbound)
- Not a prohibited class (confirm)
- Not a prohibited class (confirm)
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| FDA status | Approved (Ozempic / Wegovy) | Approved (Mounjaro / Zepbound) |
| Anti-doping (WADA) | Not a prohibited class (confirm) | Not a prohibited class (confirm) |
Cost & accessibility
- High; coverage varies
- High; coverage varies
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| Cost & access | High; coverage varies | High; coverage varies |
Strengths & limitations
Semaglutide
Tirzepatide
Frequently asked questions
Which one causes more weight loss?
In their respective trials, tirzepatide produced greater average weight loss than semaglutide, and it was superior in a head-to-head glycemic trial (SURPASS-2). Individual results vary, and both require ongoing use.
Is one clearly safer?
They share the same class side-effect profile (mainly gastrointestinal) and the same rodent thyroid warning. Semaglutide simply has more long-term and cardiovascular-outcome data by virtue of being older.
Where to go next
Related Foundations
Related Signal Records
Related biomarkers
Related conditions
Related body systems
References & sources
- STEP and SUSTAIN programs
- SELECT cardiovascular-outcomes trial
- SURMOUNT-1
- SURPASS-2 head-to-head
Educational information — not medical advice
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