Ozempic Half-Life Calculator

Ozempic is semaglutide, which the FDA label gives an elimination half-life of about 1 week. Since a medication is often considered mostly cleared after roughly five half-lives, most of a dose's estimate has faded after about five weeks. This calculator estimates the amount remaining from your logged doses and is not a blood test.

Approximately 1 week. Ozempic contains semaglutide, and the FDA prescribing information describes injectable semaglutide's elimination half-life as about 7 days. The calculator uses that value to estimate how logged doses may overlap.

Yes. Ozempic and Wegovy are both brands of semaglutide, so they share the same molecule and the same roughly 1-week half-life. They differ in their approved uses and available dose strengths, which the calculator does not weigh in on. This tool is for education, not for comparing or choosing a dose. The Wegovy half-life calculator runs the same math from that brand's page.

No. It shows a simple amount-remaining estimate from the dates and doses you enter, not a blood, plasma, or serum concentration. It cannot account for absorption, your metabolism, health conditions, or interactions, so it should never be used to make a treatment decision.

Using the label's 1-week half-life, about 5 weeks: half of the last dose's estimate is gone in 7 days, three quarters by 14, and roughly 97% by 35 days. The Ozempic label itself notes semaglutide stays in circulation for about 5 weeks after the last dose. When appetite effects fade is individual and can differ from the math.

Because a week only clears about half of each dose, every weekly shot lands on top of what remains from earlier ones. The overlapping remainders stack for roughly four to five weeks before the highs and lows settle into a repeating pattern. That build-up is expected once-weekly behavior, not a sign anything is wrong.

The half-life is about 1 week regardless of dose, so the percentage fades on the same clock. A larger dose starts from a higher amount, which means the absolute amount remaining at any day is bigger even though the share remaining is the same. The calculator makes that visible when you log different doses.

What to do about a missed dose is a prescribing decision, so take that question to your prescriber or pharmacist. For reference, the official Ozempic label instructions say to take a missed dose as soon as possible within 5 days of the missed dose, and to skip it and resume on the regular weekly day once more than 5 days have passed. The chart itself only shows how your estimated level tapers between shots rather than vanishing, so the overlap the math describes stays visible.

Some people notice early appetite effects within the first days, but the level itself builds for about 4 to 5 weeks of weekly dosing before settling into a steady rhythm, which is exactly the build-up this calculator draws. How that translates into effects for you, and how a dose is judged over time, are prescriber-guided questions.

Commonly, yes. As the estimate declines over the roughly 5 weeks after a last dose, published follow-up research reports appetite returning and weight regain being common. The calculator only shows the fading level; planning around stopping belongs with your prescriber.

A week after your last Ozempic shot, about half of that dose's estimate is still present, which is the overlap window the chart makes visible. Switch timing follows label rules and your prescriber's plan; the calculator shows the fade but never schedules a switch.

No. Clearance runs on the roughly 1-week half-life, and drinking more water, sweating, or fasting does not meaningfully speed it up. Time is the variable. If a side effect makes you want it gone sooner, contact your prescriber rather than waiting it out alone.

Yes. It is free, needs no account, and calculates entirely in your browser tab. Your dose dates and amounts are not placed in the URL or sent to MeAgain's servers or analytics. For the same tool with both semaglutide and tirzepatide, use the full GLP-1 half-life calculator.