Semaglutide vs Tirzepatide
Semaglutide vs Tirzepatide: mechanism, evidence, and cost
How semaglutide and tirzepatide compare on mechanism, weight-loss evidence, oral options, CV data, and compounded cost.
Semaglutide and Tirzepatide are different molecules: Semaglutide is a single GLP-1 receptor agonist, while Tirzepatide is a dual GIP and GLP-1 receptor agonist. In head-to-head and cross-trial terms, tirzepatide has produced larger average weight loss (~20.9% in SURMOUNT-1) than semaglutide (~14.9% in STEP 1), while semaglutide has the additional SELECT cardiovascular outcome evidence and an approved oral form. Compounded versions of either are not FDA approved.
If you are specifically considering semaglutide
If you are weighing semaglutide specifically, its distinguishing strengths are evidence breadth rather than peak weight loss: it is the only one of the two with a cardiovascular outcome trial behind it (SELECT), the only one with an approved oral form, an adolescent indication, and the longer real-world track record. For someone whose priorities include cardiovascular risk or the option of an approved oral product, that profile can matter more than the few extra percentage points tirzepatide averages. Compounded semaglutide is also generally the cheaper of the two.
There is also a sequencing argument some clinicians make: because semaglutide has the broader outcome evidence and an oral option, it is sometimes tried first, with tirzepatide considered if response is inadequate. That is a clinical judgment, not a rule, and it says nothing about compounded or microdose versions of either, which sit outside all of this trial evidence.
Head-to-head on the facts
| Dimension | Semaglutide | Tirzepatide |
|---|---|---|
| Mechanism | Single GLP-1 agonist | Dual GIP + GLP-1 agonist |
| Headline weight loss | ~14.9% (STEP 1) | ~20.9% (SURMOUNT-1) |
| Approved oral form | Yes (Rybelsus, diabetes) | No |
| CV outcome trial | SELECT (~20% MACE reduction) | Not established for weight indication |
| Compounded cost (NexLife 12-mo) | $145/mo | $186/mo |
| Brands | Wegovy / Ozempic / Rybelsus | Zepbound / Mounjaro |
Headline mean weight loss, approved products (%) — different trials and populations — not a head-to-head RCT of these exact figures
How to choose (with a clinician)
The larger average weight loss with tirzepatide is real but comes from a different trial and population, so the percentages are not a perfectly matched head-to-head. Semaglutide's cardiovascular outcome data and approved oral option matter for some people. Tolerability, cost, and medical history often decide it in practice — which is a conversation for a prescriber, not a checkout page.
What the evidence shows
- Both molecules produce clinically meaningful weight loss at approved doses.
- Tirzepatide's average weight loss is higher across trials; semaglutide has SELECT CV evidence.
What the evidence does not show
- That the cross-trial percentages equal a head-to-head RCT result.
- That compounded versions of either share the approved evidence.
Frequently asked questions
Which is better for weight loss, semaglutide or tirzepatide?
On average, tirzepatide produced more weight loss (~20.9%) than semaglutide (~14.9%), but in different trials. Choice depends on medical history, tolerability, and cost.
Is one cheaper when compounded?
Compounded semaglutide is generally cheaper than tirzepatide; at NexLife, $145/mo vs $186/mo standard at the 12-month tier.
Not medical advice. This page is consumer education, not medical advice, and does not recommend a dose, product, or provider. Compounded medications are not FDA approved. Talk with a licensed clinician about your situation.