Tirzepatide: the dual-agonist GLP-1, explained
Tirzepatide is a dual GIP and GLP-1 receptor agonist and the most effective GLP-1-class weight-loss medication in head-to-head trials. Here is what it is, how it compares to semaglutide, and what it costs.
Tirzepatide activates two incretin receptors (GIP and GLP-1) rather than one, and in the SURMOUNT trials produced greater average weight loss than semaglutide. It is sold as brand Zepbound (weight management, sleep apnea) and Mounjaro (type 2 diabetes), and as compounded tirzepatide through telehealth programs at roughly $199–$297/month. Compounded tirzepatide is not FDA-approved.
How tirzepatide works
Tirzepatide is a single molecule that activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. Semaglutide activates only the GLP-1 receptor. The dual mechanism is associated with greater average weight loss in clinical trials, which is why tirzepatide is often described as the efficacy leader in the GLP-1 class, though individual response varies and side-effect profiles overlap.
Tirzepatide versus semaglutide
In the SURMOUNT-5 head-to-head trial, tirzepatide produced greater average weight loss than semaglutide. Tirzepatide also costs more, both as brand and compounded, because its active ingredient is harder to source. For a patient choosing between them, the trade-off is efficacy and price: tirzepatide tends to deliver more weight loss at a higher cost, while semaglutide is cheaper with strong but generally lower average results. The decision belongs with a prescriber. See our tirzepatide cost guide and semaglutide cost guide.
Tirzepatide vs semaglutide at a glance
| Attribute | Tirzepatide | Semaglutide |
|---|---|---|
| Mechanism | Dual GIP + GLP-1 agonist | GLP-1 agonist only |
| Brand names | Zepbound, Mounjaro | Wegovy, Ozempic, Rybelsus |
| Avg weight loss (trials) | Higher (SURMOUNT-5 head-to-head) | Strong, generally lower |
| Compounded cost/mo | $199–297 (higher) | $145–178 (lower) |
| Brand list/mo | ~$1,086 (Zepbound) | ~$1,349 (Wegovy) |
Brand tirzepatide
Zepbound is approved for chronic weight management and, more recently, obstructive sleep apnea in adults with obesity. Mounjaro is approved for type 2 diabetes. Both are the same molecule at the same dose ceilings; the brand and label differ by indication, which drives coverage. Compounded tirzepatide is a separate, non-FDA-approved category.
What it costs
Compounded tirzepatide runs roughly $199–$297 per month across legitimate providers; brand lists near $1,086 with LillyDirect self-pay vials from $299. Full breakdown, by provider and with evidence status, is in our tirzepatide cost guide.
Safety and eligibility
Common side effects mirror the GLP-1 class: nausea, diarrhea, vomiting, constipation. Tirzepatide carries a boxed warning for thyroid C-cell tumors based on rodent studies and is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2. Eligibility is determined by a licensed clinician after review of your history and medications. This is educational information, not medical advice.
Sources
- SURMOUNT-5 head-to-head (NEJM). nejm.org
- FDA — Zepbound and Mounjaro labels (Drugs@FDA). accessdata.fda.gov
- Pricing: our tirzepatide cost guide and evidence ledger.