Is tirzepatide better than semaglutide for weight loss?

In the SURMOUNT-5 head-to-head trial, tirzepatide produced greater average weight loss (about 20% vs about 14% over 72 weeks). Individual results vary, and the right choice depends on health history, tolerance, cost and a clinician's advice.

What is the difference between semaglutide and tirzepatide?

Semaglutide activates one hormone receptor (GLP-1). Tirzepatide activates two (GIP and GLP-1). Both slow stomach emptying and reduce appetite.

Do semaglutide and tirzepatide have the same side effects?

Largely yes. Both mainly cause digestive side effects, most often while the dose is being increased. Both labels warn about pancreatitis, gallbladder problems and thyroid C-cell tumours seen in rodents.

Can you switch from semaglutide to tirzepatide?

People do switch under medical supervision, but there is no single standard switching protocol. This is a decision for a prescribing clinician.

Head-to-head comparison

Semaglutide vs Tirzepatide

Both are FDA-approved weekly injections for weight management and type 2 diabetes. In the only direct head-to-head obesity trial, tirzepatide produced more weight loss on average. Here is how they differ.

The short answer

Tirzepatide acts on two appetite and blood-sugar hormones (GIP and GLP-1); semaglutide acts on one (GLP-1). In SURMOUNT-5, people on tirzepatide lost about 20% of body weight on average over 72 weeks, compared with about 14% on semaglutide. Side effects are similar and mostly digestive.

Side-by-side

	Semaglutide	Tirzepatide
Drug class	GLP-1 receptor agonist	Dual GIP + GLP-1 receptor agonist
Brand names	Ozempic, Rybelsus (diabetes); Wegovy (weight)	Mounjaro (diabetes); Zepbound (weight)
How often	Once-weekly injection (daily tablet form also exists)	Once-weekly injection
Key obesity trial	STEP 1: about 15% average weight loss at 68 weeks	SURMOUNT-1: about 21% at 72 weeks on the top dose
Head-to-head (SURMOUNT-5)	About 14% average weight loss at 72 weeks	About 20% average weight loss at 72 weeks
Other approved uses	Type 2 diabetes; heart-attack and stroke risk reduction (Wegovy)	Type 2 diabetes; obstructive sleep apnoea with obesity (Zepbound)
Common side effects	Nausea, diarrhoea, vomiting, constipation	Nausea, diarrhoea, vomiting, constipation
FDA status	Prescription medicine	Prescription medicine

How they work

Semaglutide

Mimics GLP-1, a gut hormone released after eating. It increases insulin when blood sugar is high, slows stomach emptying and signals fullness to the brain.

Full semaglutide research guide →

Tirzepatide

Activates both GLP-1 and GIP receptors. GIP is a second gut hormone involved in insulin release and fat metabolism; adding it appears to strengthen the overall effect.

Full tirzepatide research guide →

Common questions

Is tirzepatide better than semaglutide for weight loss?: In the SURMOUNT-5 head-to-head trial, tirzepatide produced greater average weight loss (about 20% vs about 14% over 72 weeks). Individual results vary, and the right choice depends on health history, tolerance, cost and a clinician's advice.
What is the difference between semaglutide and tirzepatide?: Semaglutide activates one hormone receptor (GLP-1). Tirzepatide activates two (GIP and GLP-1). Both slow stomach emptying and reduce appetite.
Do semaglutide and tirzepatide have the same side effects?: Largely yes. Both mainly cause digestive side effects, most often while the dose is being increased. Both labels warn about pancreatitis, gallbladder problems and thyroid C-cell tumours seen in rodents.
Can you switch from semaglutide to tirzepatide?: People do switch under medical supervision, but there is no single standard switching protocol. This is a decision for a prescribing clinician.

Sources

Educational content only, not medical advice. Talk to a licensed clinician before starting or switching any medicine.