A once-a-week shot sounds like it should be gone in a week. It isn't. Here's what the Ozempic label says about how long it lasts, why, and what that means in everyday life.
What is a half-life?
A half-life is the time it takes for the amount of a medicine in your blood to drop by half. After one half-life, half is left. After two, a quarter is left, and so on.
For semaglutide, the elimination half-life is approximately 1 week (Ozempic label, section 12.3).
Why does Ozempic last so long?
- It soaks in slowly. The shot goes into the fatty layer just under the skin (MedlinePlus). From there it moves into the blood slowly. The label says the highest level is reached 1 to 3 days after the dose.
- Your own GLP-1 is gone in minutes. The GLP-1 your body makes is switched off by an enzyme called DPP-4, and it lasts under 2 minutes (Ahrén & Schmitz, 2004). Semaglutide is stabilized against that enzyme (Ozempic label, section 12.1).
- It rides on albumin. Albumin is a protein in your blood, and more than 99% of semaglutide is bound to it. The label says albumin binding is the main reason it lasts: it lowers how fast the kidneys clear it and protects it from being broken down (sections 12.1 and 12.3).
How long is Ozempic in your system after the last shot?
“With an elimination half-life of approximately 1 week, semaglutide will be present in the circulation for about 5 weeks after the last dose.”
- Ozempic shot: about 5 weeks after the last dose.
- Wegovy: about 5 to 7 weeks after the last injectable dose of 2.4 mg or 7.2 mg or oral dose of 25 mg (Wegovy label, section 12.3).
- Ozempic and Rybelsus tablets: a half-life of about one week, and present for about five weeks after the last tablet (tablets label, section 12.3).
When do levels even out?
Each weekly shot lands on top of what's left from the last one. So the level builds up for a while and then holds steady. The label says steady-state exposure is reached after 4 to 5 weeks of once-weekly doses.
How does that compare with other GLP-1 medicines?
| Medicine | Half-life |
|---|---|
| Semaglutide (Ozempic, Wegovy) | About 1 week |
| Tirzepatide (Mounjaro, Zepbound) | About 5 days |
| Orforglipron (Foundayo, daily pill) | About 29 to 49 hours |
The Mounjaro label also says tirzepatide peaks 8 to 72 hours after a dose and reaches steady state after 4 weeks of weekly doses.
What does a long half-life mean in real life?
- A missed dose. The label says to give it as soon as possible within 5 days after the missed dose. After more than 5 days, skip it and go back to the usual day (section 2.1). If you're not sure what to do, ask your prescriber.
- Pregnancy. Because of the long washout period, the label says to discontinue Ozempic at least 2 months before a planned pregnancy (section 8.3). If you're planning a pregnancy, talk to your doctor early.
- Surgery or a procedure. Tell your healthcare team before any planned surgery or procedure that you take it (section 5.10).
- Any change to your plan is your prescriber's call.
Do kidneys, liver or age change how long it lasts?
The label says age, sex, race, ethnicity and kidney impairment don't have a clinically meaningful effect on how semaglutide moves through the body, and liver impairment has no impact on exposure (section 12.3).
How Checkin helps in your first weeks
Checkin is a free AI companion for GLP-1s that you text. For this part of life on a GLP-1, it does three things:
- Text “took my shot”
It's logged, so you can see your weeks add up.
- It checks in two days after your shot
A quick text to see how you're feeling, timed to your shot day.
- Ask anything
Plain answers from the FDA label, with a picture when it helps.
