Semaglutide and tirzepatide are the two names at the center of almost every GLP-1 conversation. They are related, they are not the same, and the honest answer to "which one is better" is: that is a question for a physician who has seen your history — not for a marketing page.
Here is what actually separates them.
They work through different pathways
Both act on the body's incretin system — the hormone signals your gut releases around eating that influence blood sugar and appetite. The difference is how many of those signals each one engages.
- Semaglutide is a GLP-1 receptor agonist. It acts on the GLP-1 pathway.
- Tirzepatide is a dual agonist. It acts on GLP-1 and GIP, a second incretin pathway. That is why it is not accurate to call tirzepatide "a GLP-1" — it is a GIP/GLP-1 medicine.
Whether engaging a second pathway matters for a given person is exactly the kind of thing a clinician weighs. More mechanisms is not automatically "more suitable for you."
What the approved-brand trials reported
The clearest evidence comes from the FDA-approved, brand-name forms of each molecule and their own clinical trials — not from compounded preparations, which carry no outcome claims.
- The approved form of semaglutide, in its STEP 1 trial, showed an average 14.9% total body-weight reduction at 68 weeks on the highest studied dose.
- The approved form of tirzepatide, in its SURMOUNT-1 trial, showed an average 20.9% at 72 weeks on the highest studied dose.
Two cautions that matter more than the numbers: these were different trials, with different participants and different lengths, so they are not a clean head-to-head, and both results were as an adjunct to a reduced-calorie diet and increased physical activity — not stand-alone effects, and not a prediction of any individual's outcome. Results vary and not everyone qualifies.
Compounded versions are a separate question
At OS Reboot, compounded semaglutide and compounded tirzepatide are offered only as part of physician-directed metabolic care. They are not FDA-approved, are not copies of the branded products, and carry no weight-loss claims — the trial figures above describe the approved brands, not the compounded preparations. A licensed physician decides whether a compounded preparation is appropriate at all.
Practical differences people actually ask about
- Dosing rhythm. Both are typically weekly routines; a physician sets and adjusts the specifics. Some compounded options also come in non-injectable forms — a clinician decides what fits.
- Tolerability. Both share the GLP-1 class side-effect profile (nausea and other GI effects are the common early ones). How a specific person tolerates one versus the other is individual and is part of why titration and follow-up exist.
- Cost. The two are priced differently; see each program's page for current pricing.
The honest bottom line
Tirzepatide engages an extra pathway and its approved-brand trial reported a higher average than semaglutide's — but those are different studies, the figures belong to the FDA-approved products, and the right choice depends on your health history, other conditions, tolerability, and what a physician judges appropriate. The useful next step isn't picking a molecule off a page; it's a medical review.
You can read more about compounded semaglutide and compounded tirzepatide, and a licensed physician decides what is appropriate only after reviewing your information.
Educational information about GLP-1 medications, not medical advice, a diagnosis, or a prescription. OS Reboot does not practice medicine or operate a pharmacy; every medical decision is made by a licensed clinician based on your individual evaluation.