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Comparison

Tirzepatide vs semaglutide

Two molecules behind six brands. Here's what differs.

Clinician review pending Updated

Tirzepatide

Zepbound · Mounjaro

vs

Semaglutide

Wegovy · Ozempic · Rybelsus

Side by side

TirzepatideSemaglutide
ClassGIP and GLP-1 receptor agonistGLP-1 receptor agonist
BrandsZepbound, MounjaroWegovy, Ozempic, Wegovy pill, Rybelsus
Formsweekly injectionweekly injection or daily tablet
Half-lifeAbout 5 days, which is why it's dosed once a weekAbout 1 week for the injection, so steady levels take 4 to 5 weeks
Weight trial (highest dose)20.9% (SURMOUNT-1, 72 wk)14.9% (STEP 1, 68 wk)
Head-to-head (SURMOUNT-5)about 20.2%about 13.7%
Nausea, weight labels25% to 29%44%

The main difference

Tirzepatide acts on two gut-hormone receptors, GIP and GLP-1. Semaglutide acts on GLP-1 only. In SURMOUNT-5, a 72-week head-to-head trial published in 2025, adults with obesity lost an average of about 20.2% on tirzepatide vs about 13.7% on semaglutide. That's the only direct comparison; other figures come from separate trials.

Trial weight loss

Tirzepatide 15 mgSURMOUNT-1 · 72 wk
20.9%
Tirzepatide 10 mgSURMOUNT-1 · 72 wk
19.5%
Semaglutide 2.4 mgSTEP 1 · 68 wk
14.9%
Oral semaglutide 25 mgOASIS 4 · 64 wk
13.6%

Explainer · 0:23

1 · THE GUT HORMONE GLP-1 the medicine copies it and lasts for days 2 · SLOWER EMPTYING full sooner, full for longer 3 · THE BRAIN lowhigh HUNGER 4 · BLOOD SUGAR blood sugar after a meal + insulin withoutwith GLP-1 tirzepatide: + GIP 0:23 · voiced · captions on
After you eat, your gut releases a hormone called GLP-1. GLP-1 medicines copy it, but last much longer in the body.
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How GLP-1 medicines work
Read the transcript
  1. After you eat, your gut releases a hormone called GLP-1. GLP-1 medicines copy it, but last much longer in the body.
  2. It slows how fast your stomach empties, so you feel full sooner and stay full for longer.
  3. It also acts on appetite centers in the brain, which quiets hunger and constant thoughts about food.
  4. When blood sugar is high, it helps the pancreas release insulin. Tirzepatide also acts on a second gut hormone, GIP.

Common questions

Is tirzepatide stronger than semaglutide?

In SURMOUNT-5, a 72-week head-to-head trial published in 2025, adults with obesity lost an average of about 20.2% on tirzepatide vs about 13.7% on semaglutide. That's the only direct comparison; other figures come from separate trials.

Are tirzepatide and semaglutide the same?

No. Tirzepatide targets GIP and GLP-1 receptors; semaglutide targets GLP-1 only.

Sources

  1. SURMOUNT-1 (NEJM 2022)
  2. STEP 1 (NEJM 2021)
  3. SURMOUNT-5 head-to-head trial (NEJM 2025)

Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error