Mounjaro Half-Life
See the dosage chart to find out how long Mounjaro stays in your system.
Chart your Mounjaro injection half-life
How Mounjaro dosing works
Mounjaro starts at 2.5 mg once a week for 4 weeks, then increases to 5 mg. If needed, the dose goes up in 2.5 mg steps after at least 4 weeks on each dose. In the EU and the UK the maintenance doses are 5 mg, 10 mg and 15 mg, and 15 mg is the maximum.
In the United States, Mounjaro is approved for type 2 diabetes and the same medicine for weight management is sold as Zepbound, with the same dose steps. Zepbound dosage chart and half-life →
- Starting doseMonth 1Weeks 1–42.5 mgonce a week
- Maintenance optionMonth 2Weeks 5–85 mgonce a week
- Step upMonth 3Weeks 9–127.5 mgonce a week
- Maintenance optionMonth 4Weeks 13–1610 mgonce a week
- Step upMonth 5Weeks 17–2012.5 mgonce a week
- Maximum doseMonth 6 onwardWeek 21 onward15 mgonce a week
Mounjaro dosing schedule by week
| When | Weekly dose | What this step is for |
|---|---|---|
| Weeks 1–4Month 1 | 2.5 mg | Starting doseHelps your body get used to tirzepatide. In the US, where Mounjaro is for type 2 diabetes, 2.5 mg can also be continued. |
| Weeks 5–8Month 2 | 5 mg | Maintenance optionFirst increase, from week 5 at the earliest. The lowest maintenance dose. |
| Weeks 9–12Month 3 | 7.5 mg | Step upNext step from week 9 at the earliest, if more effect is needed. |
| Weeks 13–16Month 4 | 10 mg | Maintenance optionFrom week 13 at the earliest. A maintenance dose. |
| Weeks 17–20Month 5 | 12.5 mg | Step upFrom week 17 at the earliest, on the way to 15 mg. |
| Week 21 onwardMonth 6 onward | 15 mg | Maximum doseFrom week 21 at the earliest. The highest maintenance dose. |
Get reminders for every Mounjaro jab and track each dose step in Glapp
Rated Excellent on Trustpilot. (opens in a new tab)
How long does Mounjaro stay in your system?
Mounjaro (tirzepatide) has a half-life of about 5 days. After your last jab the level falls by about half every 5 days: roughly 17% of the peak is left after 2 weeks and less than 3% after about 4 weeks, so most of it has left your body about a month after the last dose.
- Half-life
- About 5 days
- Highest level
- 8 to 72 hours after a jab, typically about 24 hours
- Steady state
- After about 4 weeks on the same dose
- Mostly cleared (under 3%)
- About 4 weeks after the last dose
The Mounjaro prescribing information does not give a washout time. At 5 half-lives, the usual rule of thumb, tirzepatide is mostly cleared after about 25 days.
Mounjaro is the tirzepatide brand used for weight management in the EU, the UK, Brazil and many other countries. In the United States it is approved for type 2 diabetes, and the same medicine for weight management is sold as Zepbound.
Mounjaro half-life chart
Estimated share of the medicine left after your last jab, compared with the highest level just after that jab. It assumes you had been on the same dose for at least 4 weeks.
| Time since your last jab | Estimated level left |
|---|---|
| 1 week (7 days) | 44% |
| 2 weeks (14 days) | 17% |
| 3 weeks (21 days) | 6.4% |
| 4 weeks (28 days) | 2.4% |
| 5 weeks (35 days) | 0.9% |
| 6 weeks (42 days) | 0.3% |
When to increase your Mounjaro dose
Each increase needs at least 4 weeks on the current dose. Your prescriber increases the dose only if you need more effect and tolerate the current one.
Going up slowly limits nausea, diarrhoea and vomiting. The EU label notes that these side effects are more common while the dose is being increased and become less frequent over time.
What is the maximum dose of Mounjaro?
The maximum dose of Mounjaro is 15 mg once a week for adults. With the minimum 4-week steps, the earliest you can reach it is week 21.
For children aged 10 and over with type 2 diabetes, the maximum is 10 mg.
Mounjaro pens and strengths
In the UK, Mounjaro comes as a KwikPen that holds 4 weekly doses, in strengths from 2.5 mg to 15 mg. In the EU, single-dose pens, vials and KwikPens are approved, and which ones you get depends on the country.
In Brazil, Mounjaro is sold as single-dose pens. In the US, it comes as single-dose pens and vials.
If you miss a dose of Mounjaro
If you miss a dose, take it within 4 days (96 hours). If more than 4 days have passed, skip the missed dose and take the next one on your usual day.
You can change your injection day as long as the two doses are at least 3 days (72 hours) apart.
Mounjaro KwikPen doses and clicks
Each KwikPen delivers 4 fixed weekly doses of the strength printed on the pen. The label does not include taking partial doses from a KwikPen.
Some people count clicks to take a smaller dose. That is off-label; if your prescriber agrees to it, the Mounjaro click chart shows how many clicks match a dose.
After one dose vs. after months on Mounjaro
The level falls by about half every 5 days, whether you took a single jab or have been on Mounjaro for months. What changes is the starting point: after several weeks on the same dose the jabs overlap, and the peak is about 1.6 times higher than after one jab, so there is more to clear. As a share of the peak, the timeline in the table above applies either way.
Why Mounjaro can feel weaker before your next jab
Mounjaro peaks about 20 hours after a jab, once you are on a steady dose. By the day of your next weekly jab, the estimated level is about 44% of that peak, so some people notice more hunger or fewer side effects late in the week. This is expected with once-weekly dosing. If it bothers you, talk to your prescriber rather than changing your schedule on your own.
Can you flush Mounjaro out of your system faster?
No. There is no proven way to speed up how your body clears tirzepatide. Drinking more water, exercising or fasting does not shorten its half-life, because it is broken down slowly by normal metabolism rather than flushed out. If side effects are the problem, contact your healthcare professional.
Stopping Mounjaro before surgery or pregnancy
Pregnancy: the EU and UK labels advise stopping Mounjaro at least 1 month before a planned pregnancy because of its long half-life. The US label says to stop it when a pregnancy is recognised.
Birth control pills: the US, UK and Brazil labels advise a non-oral method, or adding a barrier method, for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase. The EU label says no change to oral contraceptives is needed.
Surgery: Mounjaro slows stomach emptying, which can matter under anaesthesia or deep sedation. Tell your surgeon and anaesthesia team that you take it; they will tell you whether and when to pause it.
Frequently asked questions about Mounjaro
What is the starting dose of Mounjaro?
2.5 mg once a week for 4 weeks. In the EU and the UK it is a starting dose only, while the US label allows staying on 2.5 mg for type 2 diabetes.
How often can you increase the Mounjaro dose?
No sooner than every 4 weeks, in 2.5 mg steps, and only when your prescriber decides you need it.
What is the highest dose of Mounjaro?
15 mg once a week for adults. It can be reached in week 21 at the earliest.
Do you have to go up to 15 mg?
No. The maintenance doses are 5 mg, 10 mg and 15 mg, and you can stay on a lower dose if it works for you.
How many doses are in a Mounjaro KwikPen?
4 weekly doses of the strength shown on the pen, which covers 4 weeks of treatment.
Is Mounjaro dosing the same as Zepbound?
Yes. Both are tirzepatide, with the same dose steps from 2.5 mg to 15 mg.
What is the half-life of Mounjaro?
About 5 days, according to the prescribing information. Because of this long half-life, Mounjaro is injected once a week.
How long does Mounjaro stay in your system after stopping?
The level halves about every 5 days. After 2 weeks roughly 17% of the peak is left, after 3 weeks about 6%, and after about 4 weeks less than 3%. You can think of it as gone about a month after the last jab.
Is Mounjaro out of your system after 2 weeks?
Not completely. About 2 weeks after the last jab, roughly 17% of the peak level is still in your body. It takes about 4 weeks to fall below 3%.
When does Mounjaro peak after an injection?
Between 8 and 72 hours after a jab, typically around 24 hours, according to the prescribing information.
Why does Mounjaro wear off after 4 or 5 days?
With weekly jabs, the estimated level before the next dose is about 44% of the peak, so some people feel the effect fade late in the week. If the dip bothers you, talk to your prescriber rather than changing the schedule yourself.
Are Mounjaro and Zepbound the same medicine?
Yes. Both are tirzepatide from Eli Lilly, with the same half-life and dose steps. The brand name depends on the country and on what the medicine is approved for.
Does the KwikPen change how long Mounjaro lasts?
No. The KwikPen holds 4 weekly doses, but each dose is the same tirzepatide as a single-dose pen, so the half-life and levels are the same.
How the estimate works
The calculator uses a one-compartment model with first-order absorption, the standard way to describe a weekly injection. It uses average values for tirzepatide: a half-life of 5 days, a peak 1 day after a single jab and 80% absorption from the injection site. Real levels vary from person to person, and the model does not show how well the medicine works for you.
Data Sources
Label facts on this page come from these sources:
- Mounjaro EU product information — EMA summary of product characteristics
- Mounjaro US prescribing information — Eli Lilly, FDA-approved label
- Tirzepatide clinical pharmacology review — FDA, NDA 215866
Check Our Other Free Tools
- Zepbound dosage chart and half-life
- Mounjaro click chart
- Tirzepatide units calculator
- GLP-1 dose plotter
- Titration planner
- Missed dose guide
Important
This page is general information, not medical advice. Levels shown are estimates from a model, not lab results. Follow your prescriber and the instructions that come with your medicine.