Wegovy Half-Life Calculator

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

About 1 week. The FDA Wegovy prescribing information lists an elimination half-life of approximately 7 days for injectable semaglutide, and the calculator uses that value to estimate how your logged doses overlap.

For half-life, yes. Wegovy and Ozempic are both semaglutide, so they share the same molecule and the same roughly 1-week half-life. Their brand names, approved uses, and dose strengths differ, but the decay math the calculator uses is identical. The tool is for education, not for choosing between them. The Ozempic 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 level. It cannot model absorption, your metabolism, health conditions, or interactions, so it must not 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 Wegovy label itself notes semaglutide can remain in circulation for about 5 to 7 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 on any day is bigger even though the share remaining is the same. Logging different doses in the calculator makes that visible.

What to do about a missed dose is a prescribing decision, so take that question to your prescriber or pharmacist. For reference, the official Wegovy label instructions say to take a missed dose as soon as possible when your next scheduled dose is more than 2 days (48 hours) away, and to skip it and resume on the regular day when the next dose is less than 2 days away. 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 weight change for you is individual and prescriber-guided.

Commonly, yes. As the estimate declines in the 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 Wegovy 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, requires no account, and runs entirely in your browser tab. Your dose dates and amounts stay local and are never added to the URL or sent to MeAgain's servers or analytics. For semaglutide and tirzepatide in one place, use the full GLP-1 half-life calculator.