Tirzepatide Half-Life Calculator for Mounjaro, Zepbound & Compounded Tirzepatide

About 5 days. The FDA prescribing information describes tirzepatide's elimination half-life as approximately 5 days, and this calculator uses that value for every shot you enter. Because the number belongs to the tirzepatide molecule, it is the same whether you take Mounjaro, Zepbound, or compounded tirzepatide. A 5-day half-life means a single dose's estimate halves every five days: roughly 50% left at day 5, 25% at day 10, and on down the line. That is a little quicker than semaglutide's week-long fade, so the tirzepatide curve dips a bit lower between weekly shots. The tool turns that published number into a curve from your own dates, so you can read where a dose sits on any day without treating the line as a lab result.

Most of a dose is gone in about 25 days, a little over three weeks. With a half-life of about 5 days, roughly 97% of a tirzepatide dose has cleared after five half-lives: half of the last shot's estimate fades in the first five days, three quarters by ten, and only a few percent is left by day 25. Scrub this calculator's timeline forward past your final shot to watch your own estimate drop toward the bottom of the chart. As with any GLP-1, when the appetite effect eases after stopping is a separate, personal question that can run on a different clock than the math, so treat the fading curve as background rather than a cue to change anything on your own.

Yes. The roughly 5-day half-life is a property of the tirzepatide molecule, so the calculator uses the same value for compounded tirzepatide that it uses for a branded pen. Enter your dose and dates exactly as you would for Mounjaro or Zepbound and the curve is drawn the same way. What the calculator cannot know is anything specific to how a given compounded prescription was prepared or how your body takes it in, which is one reason the line is an estimate for learning rather than a measurement. For anything about your compounded medicine, its strength, or its schedule, follow the instructions you were given and ask the pharmacy or prescriber that provided it.

Using the label's 5-day half-life, about 25 days. Half of the last dose's estimate is gone in 5 days, three quarters by 10, and roughly 97% by 25 days, which is the five-half-lives mark most people mean by mostly cleared. The remaining sliver keeps shrinking but never reaches an exact zero on paper. The GLP-1 half-life calculator shows the same fade next to semaglutide if you want to compare the two side by side. Whatever the chart shows, when to expect changes in appetite or weight after stopping is individual, so keep those questions with your prescriber rather than reading them off the curve.

Each weekly shot lands while roughly a third of the previous one's estimate is still present — seven days on a 5-day half-life leaves about 38%. Those leftovers stack for the first few weeks until the amount cleared between shots matches the amount added, and the peaks and valleys settle into a repeating pattern. That build-up is expected once-weekly behavior, not a sign anything is wrong, and it is part of why the first weeks can feel different from later ones. The calculator draws that climb straight from the dates you enter, so if you have been on tirzepatide longer than the default history, add earlier shots to see the fuller picture rather than just the most recent stretch.

Commonly, yes. As the estimate declines over the roughly 25 days after a last dose, published follow-up research on tirzepatide reports appetite returning and weight regain being common once the medicine is stopped. The calculator only shows the fading level from your dates; it does not predict how your appetite will respond, which varies from person to person. If you are thinking about stopping, tapering, or switching, that belongs with your prescriber, who can weigh your history and goals. Use the fading curve here as a way to picture the timing, not as a plan. For the same fade alongside semaglutide, open the GLP-1 half-life calculator.