Blog · Updated September 26, 2026 · By the team building Embera
Short answer
The half-life of a medication is the time it takes for the amount in your body to drop by half. Semaglutide (Wegovy, Ozempic) has a half-life of about 7 days, and tirzepatide (Zepbound, Mounjaro) about 5 days, which is why both can be taken once a week.
Half-life tells you how fast your body clears a medication. After one half-life, about half of a dose is left; after two, a quarter; and so on.
Medication
Molecule
Half-life
Wegovy, Ozempic, Rybelsus
Semaglutide
About 7 days
Zepbound, Mounjaro
Tirzepatide
About 5 days
A long half-life means each weekly dose adds to what is left of the last one, so the level builds up over the first 4 to 5 weeks on a dose before it settles. A common rule of thumb says a medication is mostly cleared after about 5 half-lives.
Embera is a personal tracking app, not a medical service, and the people writing these guides are not clinicians. This article is general information, not medical advice. Always follow your prescriber's or pharmacist's instructions.