Semaglutide vs. tirzepatide: what's the difference?

Updated 2026-09-29 · Reviewed for accuracy by the EKO Labs team. Educational only; not medical advice.

Semaglutide and tirzepatide are both once-weekly prescription injections. Both are FDA-approved for type 2 diabetes and for chronic weight management in eligible adults. The main difference is how they work.

How they work

• Semaglutide acts on one hormone receptor: GLP-1.
• Tirzepatide acts on two: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide).

What each is approved for

• Semaglutide: type 2 diabetes (Ozempic®); chronic weight management and cardiovascular risk reduction in eligible adults (Wegovy®).
• Tirzepatide: type 2 diabetes (Mounjaro®); chronic weight management and moderate-to-severe obstructive sleep apnea in adults with obesity (Zepbound®).

Safety

Both carry the same boxed warning about thyroid C-cell tumors and have similar common side effects, mostly nausea, diarrhea, vomiting and constipation.

How does a doctor choose?

There is no single "better" medicine for everyone. Doctors consider your health history, other conditions such as heart disease or sleep apnea, other medicines you take, side effects, insurance and cost. That is why EKO Labs never recommends a medicine on this website: the choice belongs to your doctor, after a real conversation.