How long does semaglutide stay in your system?
Short answer: semaglutide has a half-life of about 7 days, meaning half of a dose clears roughly every week. After a final dose, it takes around 5 weeks (about five half-lives) for almost all of it to leave your body. Its cousin tirzepatide, in Mounjaro and Zepbound, clears a little faster at a half-life of about 5 days.
The week-by-week picture
With a 7-day half-life, a dose is at roughly 50 percent after one week, 25 percent after two, 12.5 percent after three, and so on. Because you inject weekly, each new dose lands exactly as the previous one halves, so levels stack and build over the first 4 to 5 weeks before settling into a steady rhythm. That build-up is why the first weeks on a new dose can feel different from month two on the same dose.
What this means in practice
- A late jab is not a cliff. With a week-long half-life, levels decline gradually rather than vanishing on day 8. Follow the label and your prescriber's advice on late or missed doses rather than doubling up.
- Effects outlast the last dose. After stopping, appetite effects fade over weeks, not days, as levels step down through each half-life.
- Side effect timing follows the curve. Nausea and similar effects often cluster near the peak after an injection, especially in the first weeks of a new step.
- Oral semaglutide follows the same logic. Rybelsus is taken daily, but the compound's long half-life still smooths levels across the week.
Averages are not you
Seven days is a population average. Your actual pattern depends on your doses, their exact timing, missed weeks and titration changes. That is why a generic curve from a search result can only ever be an illustration; the useful version is built from the doses you actually took.
How PepLevel handles it
PepLevel builds an estimated level curve from your own logged doses using published half-life values for semaglutide, tirzepatide and any compound you add, with a marker for right now. Log a late dose and the curve reflects it honestly. The estimate is illustrative rather than a blood measurement, but it turns "why am I so hungry today" into something you can actually see, and the basic curve is free.
See what is in your system right now
Level estimates from your actual logged doses. Coming soon to the App Store.
Get PepLevelMedical disclaimer: this guide is general information, not medical advice. Half-life figures are published averages and individual clearance varies. Level estimates in PepLevel are illustrative only and are not a measurement of your blood levels. Always follow your prescriber's instructions, including on missed doses.