This page gives general facts from the medicine label. It is not medical advice. Ask your doctor or pharmacist about your treatment.
The half-life is the time it takes for half of a medicine to leave your body. It explains why these shots are weekly, and why the medicine stays for weeks after the last dose.
The numbers on the label
- Semaglutide (Ozempic, Wegovy): about 1 week.
- Tirzepatide (Mounjaro): about 5 days.
- Tirzepatide (Zepbound): about 5 to 6 days in people with overweight or obesity.
One dose, week by week
After each half-life, half of what was left goes. With a half-life of 1 week, half stays after 1 week, a quarter after 2 weeks, and about 6% after 4 weeks.
With a dose each week
A new dose comes before the last one has gone. So the level goes up over the first weeks, then it stays in a steady range. The labels say this steady level comes after about 4 to 5 weeks for semaglutide and about 4 weeks for tirzepatide.
After the last dose
The Ozempic label says semaglutide stays in the blood for about 5 weeks after the last dose. The Wegovy label says about 5 to 7 weeks after the last 2.4 mg or 7.2 mg dose.
The medicine level in Octopoke
Octopoke uses the half-life to show an estimate of your medicine level over time. It is an estimate from your logged doses, not a blood test. Do not use it to change a dose.