Semaglutide vs tirzepatide, on the evidence
Last verified 2026-08-24 · methodology · conflict-of-interest disclosure · dataset: open JSON
The trial record, attributed properly
| Semaglutide (approved product) | Tirzepatide (approved product) | |
|---|---|---|
| Flagship trial | STEP-1: ≈14.9% at 68 weeks | SURMOUNT-1: ≈20.9% at 72 weeks (highest dose) |
| Direct head-to-head | SURMOUNT-5: ≈13.7% | SURMOUNT-5: ≈20.2% |
| Mechanism | GLP-1 | GIP + GLP-1 |
| Verified compounded floor | $69/mo | $97/mo |
Those trials tested Wegovy and Zepbound — the FDA-approved products. Compounded preparations carry the molecule, not the trial file; that evidence status is the honest asterisk on every compounded comparison, ours included.
Side effects: same family, different intensity curve
Both lead with nausea, constipation, diarrhea, and fatigue, front-loaded in titration. Trial discontinuation-for-adverse-events ran modestly higher for tirzepatide at top doses; plenty of individual patients report the reverse. Tolerability is discovered, not predicted — which is why slow titration and an adjustable provider matter more than the molecule choice.
The decision, honestly framed
Bigger average effect and budget room: tirzepatide has the stronger trial case. Tightest budget: semaglutide’s $69 floor is the market’s entry point, and ≈15% average loss is transformative, not a consolation. History of rough GI tolerance, retinopathy, thyroid-cancer family history, or pregnancy plans: that’s a prescriber conversation before a price conversation — see the safety page. Rankings: semaglutide · tirzepatide.
Update log
- 2026-08-24 — Page created per the Pass-12 audit; sources inline.