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Tirzepatide Dosage Guide
Last updated: September 2026
Tirzepatide is the active medicine in Zepbound® and Mounjaro®, and getting the dose right is what makes it both tolerable and effective. The tirzepatide dosage schedule is deliberately slow: a low starting dose, a step up every four weeks, and a maintenance dose chosen for how a patient responds rather than how high the number goes.
Tirzepatide was first approved as Mounjaro® for type 2 diabetes, and later studies showed substantial weight loss when it was combined with a reduced-calorie diet and more activity, which led to Zepbound® being approved for weight management. Zepbound® is now also approved for moderate to severe obstructive sleep apnea in adults with obesity, and its weight indication covers both losing weight and maintaining that loss long term. If you are weighing it against the once-weekly GLP-1 alternative, our Zepbound® vs Wegovy® comparison puts the two side by side.
This guide covers the full dosing ladder, the three maintenance doses, the four ways tirzepatide is now supplied, what to do about a missed dose, what the 2026 label changed, and why there is no safe way to convert a tirzepatide dose into “units.” Always follow the plan your healthcare team sets.
Key Takeaways
Tirzepatide starts at 2.5 mg once weekly for 4 weeks, then increases in 2.5 mg steps with at least 4 weeks at each dose, up to a maximum of 15 mg once weekly.
The recommended maintenance doses for weight management are 5 mg, 10 mg, or 15 mg once weekly. For obstructive sleep apnea they are 10 mg or 15 mg.
A missed dose can be taken within 4 days (96 hours). After that, skip it. The injection day can change as long as doses stay at least 3 days apart.
Since early 2026 tirzepatide is supplied four ways: a single-dose pen, a single-dose vial, a multi-dose vial, and a four-dose KwikPen® that holds a month of treatment.
In SURMOUNT-MAINTAIN, stepping down to 5 mg held most of the weight loss, while stopping treatment gave most of it back.
There is no reliable way to convert a tirzepatide dose into insulin-syringe “units” — that number depends entirely on a vial’s concentration.
Tirzepatide Dosage in Units
Zepbound® is taken once a week, on the same day each week, at any time of day, with or without food. It is injected under the skin of the stomach, thigh, or upper arm, and the injection site should be rotated to avoid irritating the same patch of skin. A healthcare provider or nurse demonstrates the first injection, after which most patients do it themselves at home, or have someone help them.
One of the most common questions about tirzepatide is how many units a dose works out to — usually because someone has been handed a vial and an insulin syringe rather than a pen. The honest answer is that the question does not have a single number behind it.
Why there is no universal “units” conversion
FDA-approved tirzepatide is measured in milligrams, and the volume is fixed by the manufacturer: 0.5 mL for every dose in a single-dose pen or single-dose vial, and 0.6 mL for every dose in the multi-dose vial and the KwikPen®. Nobody using an approved product has to measure anything.
“Units” are marks on an insulin syringe. A unit is a measure of volume on that syringe, not an amount of tirzepatide. How many milligrams sit in one unit depends entirely on how concentrated the liquid in the vial is, and compounded vials are not all made to the same concentration. That is why a units chart copied from a forum can be badly wrong for the vial in someone’s refrigerator, and why the FDA has documented dosing errors from patients and clinicians measuring doses themselves — including doses many times larger than intended.
The safe rule is simple: follow the dose written on the prescription and the concentration printed on the vial’s own label, and ask the prescriber or pharmacist to confirm the volume before injecting. Never convert from a chart found online. This is the same principle that applies across the drug class, and it is why each medicine has its own numbers — the semaglutide ladder in our semaglutide weight loss dosage chart looks nothing like the tirzepatide one, and the two are never interchangeable.
Zepbound® Pens Come in these Doses:
Zepbound® is made in six strengths. Every strength is a once-weekly dose, and the strength is fixed — there is no dial to turn on the pen.
Dose
How often
Where it sits in the schedule
2.5 mg
Once weekly
Starting dose only, for the first 4 weeks. Not a maintenance dose
5 mg
Once weekly
First possible maintenance dose
7.5 mg
Once weekly
Step-up dose
10 mg
Once weekly
Maintenance dose (and a maintenance dose for sleep apnea)
12.5 mg
Once weekly
Step-up dose
15 mg
Once weekly
Maximum dose, and a maintenance dose
Four ways tirzepatide is now supplied
This part of the picture changed in 2026. Zepbound® used to mean a single-dose pen. The FDA approved a four-dose KwikPen® in late January 2026, and Lilly made it available on February 23, 2026, so a patient can now carry a month of treatment in one device.
How it is supplied
Doses inside
Volume per dose
Room temperature limit
Single-dose pen
1
0.5 mL
21 days
Single-dose vial
1
0.5 mL
21 days
Multi-dose vial
4
0.6 mL
30 days
Single-patient-use KwikPen®
4
0.6 mL
30 days
All four are stored in the refrigerator between 2°C and 8°C (36°F and 46°F) until use. An opened multi-dose vial or KwikPen® is thrown away after 30 days, or once four weekly doses have been taken, whichever comes first — even if liquid is left inside. And a KwikPen® is for one patient only: it must never be shared, even if the needle is changed. That warning was added to the label in January 2026.
Zepbound® Dosage Schedule
The schedule is built to let the gut adjust. The starting dose is 2.5 mg once weekly for the first 4 weeks. This lower dose is there to improve tolerability, so nausea, diarrhea, and similar effects stay manageable, and most people do not see much weight change during this period. That is expected.
At week 5 the dose usually increases to 5 mg once weekly for another 4 weeks. From week 9 onward, the prescriber may increase again based on how well the patient is responding and how they are tolerating it. Increases are made in 2.5 mg steps, with at least 4 weeks at the current dose before the next one.
Timing
Dose (once weekly)
Notes
Weeks 1–4
2.5 mg
Initiation only — not a maintenance dose
Weeks 5–8
5 mg
First possible maintenance dose
Weeks 9–12
7.5 mg
Optional step up
Weeks 13–16
10 mg
Possible maintenance dose
Weeks 17–20
12.5 mg
Optional step up
Week 21 onward
15 mg
Maximum dose, and a possible maintenance dose
Two rules sit alongside that ladder and are worth knowing before they come up:
A missed dose can be taken as soon as possible within 4 days (96 hours) of the day it was due. If more than 4 days have passed, that dose is skipped and the next one is taken on the regular schedule.
The weekly injection day can be changed if needed, as long as there are at least 3 days (72 hours) between two doses.
The four-week rule is a floor, not a countdown. If a patient is struggling at a given dose, holding there longer — or stepping back to the last comfortable dose and trying again later — is a normal part of the plan. A comfortable patient who stays on treatment almost always does better than an uncomfortable one pushed to the top of the ladder.
What’s the Starting Dose for Tirzepatide?
The starting dose for weight management is 2.5 mg once weekly for 4 weeks. Its only job is to introduce the medicine gently. It is not a maintenance dose, and it is not expected to produce meaningful weight loss, which is a common source of early disappointment and early quitting. Setting that expectation on day one is one of the most useful things a prescriber can do.
After four weeks, if it is being tolerated, the dose typically moves to 5 mg once weekly. From there, adjustments of 2.5 mg every four weeks are made according to response and tolerability. The same 2.5 mg start applies to Mounjaro® for type 2 diabetes.
What’s the Maximum Dose of Tirzepatide?
The maximum recommended dose is 15 mg once weekly. In the single-dose pen and vial that dose comes as 15 mg in 0.5 mL; in the multi-dose vial and KwikPen® the same 15 mg comes in 0.6 mL, because those presentations use a different concentration. The milligrams are what matter.
The maximum is not automatically the goal. The label names three maintenance doses for weight management — 5 mg, 10 mg, or 15 mg — precisely so that a patient can settle at the lowest dose that achieves the result comfortably. Higher doses do produce more weight loss on average, as the pivotal SURMOUNT-1 trial showed over 72 weeks, but “on average” is not “for everyone.”
Average weight loss at 72 weeks — SURMOUNT-1
Tirzepatide 15 mg20.9%
Tirzepatide 10 mg19.5%
Tirzepatide 5 mg15.0%
Placebo3.1%
SURMOUNT-1, 2,539 adults with obesity or overweight without diabetes, 72 weeks (New England Journal of Medicine, 2022).
Tirzepatide Maintenance Dose After Weight Loss
Once someone reaches the weight they were aiming for, the next question is what happens to the dose. Two trials answer it directly, and the newer one is the more useful.
In SURMOUNT-MAINTAIN, published in The Lancet in 2026, 441 adults took tirzepatide at their maximum tolerated dose (10 or 15 mg) for 60 weeks, then were split three ways for another 52 weeks: stay at that dose, drop to 5 mg, or switch to placebo.
What they did after 60 weeks
Total weight change at 112 weeks
Regained at least half their loss
Stayed at 10 or 15 mg
−21.9%
8%
Stepped down to 5 mg
−16.6%
25%
Switched to placebo
−9.9%
67%
The practical reading: staying on treatment holds the result, stepping down to 5 mg holds most of it and is a reasonable alternative to stopping, and stopping gives most of it back. That matches the earlier SURMOUNT-4 trial, where people who stopped after 36 weeks regained 14.0% of their body weight over the next year while those who continued lost a further 5.5%. Obesity behaves like a chronic condition here, not a course of antibiotics — the same pattern our article on what happens when you stop taking Ozempic® describes for semaglutide.
Compounded Tirzepatide Dosage Chart
For a period during the 2023–2024 shortage, compounded tirzepatide was widely available and widely prescribed, and dosing charts for it circulated everywhere. That situation has changed, and any page still presenting a compounded ladder as a routine option is out of date. Here is where things actually stand:
The shortage ended. The FDA declared the tirzepatide shortage resolved at the end of 2024, and the grace periods that had allowed compounding pharmacies to keep making copies ran out in February and March 2025.
The FDA has moved to close bulk compounding for good. On April 30, 2026 it proposed excluding semaglutide, tirzepatide, and liraglutide from the 503B bulk drug substances list, on the basis that there is no clinical need to compound them from bulk when approved products are available. The comment period closed on June 29, 2026.
Safety reports exist. The FDA has received more than 215 adverse event reports involving compounded tirzepatide, and separately warns about products sold online as “for research purposes only,” which are unapproved drugs of unverified identity, strength, and sterility.
Dosing is where the risk concentrates. Approved products arrive with the dose already measured. Compounded vials do not, which is where the units-versus-milligrams confusion described above turns into real overdoses.
If a patient arrives already using a compounded product, the useful conversation is not a lecture. It is: what concentration is in the vial, who prescribed it, what dose are they actually taking, and how would we move them onto an approved product and a documented dosing schedule.
What Zepbound® Costs and Who Covers It
Dose questions and cost questions usually arrive together, and the answer changed twice in the past year.
Self-pay through LillyDirect: $299 a month for 2.5 mg, $399 for 5 mg, and $449 for 7.5 mg and above, available as either single-dose vials or the KwikPen®, provided each refill is bought within 45 days of the previous delivery.
Commercial insurance that covers it: as little as $25 a month for eligible patients.
Medicare: a temporary GLP-1 Bridge program running from July 1, 2026 to December 31, 2027 puts eligible Part D beneficiaries at $50 a month. For Zepbound®, it is the KwikPen® formulation that is included.
For a practice, this matters clinically as well as commercially: cost is one of the most common reasons patients stop mid-titration, and a patient who stops at 5 mg because of price is a patient whose dose decision was made by their wallet.
Zepbound® and Mounjaro®: Same Medicine, Two Labels
Both products contain tirzepatide, and both use the same 2.5 mg start, the same 2.5 mg steps, and the same 15 mg adult maximum. What differs is what they are approved to treat:
Zepbound® is approved to reduce excess body weight and maintain that reduction long term in adults with obesity, or overweight with at least one weight-related condition, and to treat moderate to severe obstructive sleep apnea in adults with obesity. For sleep apnea the maintenance doses are 10 mg or 15 mg.
Mounjaro® is approved for type 2 diabetes. Since December 2025 it is approved for children aged 10 and older as well, where the maximum is 10 mg weekly, and in August 2026 the FDA added an indication to lower the risk of major cardiovascular events in adults with type 2 diabetes at high risk, based on the 13,299-patient SURPASS-CVOT trial.
The label is explicit that tirzepatide should not be combined with another tirzepatide product or with any GLP-1 receptor agonist. If you want the pharmacology behind the difference between the two brand names, our guide to how long Mounjaro® stays in your system covers the half-life and what it means for timing.
2026 Label Updates Worth Knowing
The prescribing information was revised in August 2026, and several changes are recent enough that older guides still repeat the previous version:
The suicidal behavior and ideation warning was removed. On January 13, 2026 the FDA requested its removal from weight-management GLP-1 labels after a review covering 91 trials and a cohort of 2.2 million users found no increased risk.
Severe gastrointestinal reactions were given a strengthened section in February 2026, and tirzepatide is not recommended for patients with severe gastroparesis.
Diabetic retinopathy monitoring was added in August 2026: patients with type 2 diabetes and a history of retinopathy should be monitored for progression, since rapid improvement in glucose control can cause temporary worsening.
Oral contraceptives: patients taking the pill should add a barrier method, or switch to a non-oral method, for 4 weeks after starting tirzepatide and for 4 weeks after every dose increase. Non-oral hormonal contraception is not affected.
Anesthesia and sedation: because tirzepatide slows stomach emptying, patients should tell every provider about planned surgeries or procedures.
Unchanged: the boxed warning about thyroid C-cell tumors, and the contraindications for a personal or family history of medullary thyroid carcinoma or MEN 2, and for serious hypersensitivity to tirzepatide.
What Clinicians Should Tell Patients About Tirzepatide Dosing
Most dosing problems in practice are expectation problems. A short, consistent script prevents most of them:
The first month is a ramp, not a result. 2.5 mg exists to be tolerated, not to produce weight loss.
Slower is often better. Holding a dose an extra few weeks, or stepping back down, keeps patients on therapy — and adherence is what produces the outcome.
Coach the gut. Smaller meals, eating slowly, stopping at the first sign of fullness, staying hydrated, easing off very large or fatty meals. Most nausea during escalation is manageable and temporary.
Name the maintenance plan early. Patients should hear at the start that this is long-term treatment, that 5 mg is a legitimate maintenance dose, and what the data show about stopping.
Ask what they are actually injecting. Compounded vials, units on an insulin syringe, and internet conversion charts are where serious dosing errors come from.
These judgment calls — when to hold, when to step back, which maintenance dose to land on — are the core clinical skill in weight management, and they transfer directly to whatever comes next in the class, including the triple agonist covered in our retatrutide vs tirzepatide comparison. You can sample IAPAM’s clinical GLP-1 training with the free 1-CME module below.
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Frequently Asked Questions
What is the starting dose of tirzepatide?
The starting dose of tirzepatide for weight management is 2.5 mg injected under the skin once weekly for the first 4 weeks. It is a starting dose only, not a maintenance dose, and it is not expected to produce much weight loss on its own. After 4 weeks the dose increases to 5 mg once weekly, and it can then rise in 2.5 mg steps with at least 4 weeks at each dose.
What is the maximum dose of tirzepatide?
The maximum dose is 15 mg once weekly, for both Zepbound® for weight management and Mounjaro® for type 2 diabetes in adults. The recommended maintenance doses for weight management are 5 mg, 10 mg, or 15 mg once weekly, so many patients do well without ever reaching the maximum.
How many units is 2.5 mg of tirzepatide?
There is no single answer, and that is the important part. FDA-approved tirzepatide is dosed in milligrams in a fixed volume set by the manufacturer: 0.5 mL in a single-dose pen or vial and 0.6 mL per dose in the multi-dose vial and KwikPen®. Units are marks on an insulin syringe, not an amount of drug. How many units equal 2.5 mg depends entirely on the concentration of the vial in question, which varies between compounding pharmacies. Patients should follow the dose their prescriber wrote and the concentration printed on their own vial label, and never convert from a chart found online.
What is the tirzepatide dosage schedule for weight loss?
Weeks 1 to 4 are 2.5 mg once weekly, weeks 5 to 8 are 5 mg once weekly, and the dose can then step up by 2.5 mg at a time, to 7.5 mg, 10 mg, 12.5 mg, and a maximum of 15 mg, with at least 4 weeks at each dose. The four-week rule is a minimum, not a schedule to rush. A prescriber may hold a dose longer or step back down if side effects are troublesome.
What happens if a dose of tirzepatide is missed?
If the missed dose is caught within 4 days (96 hours), it can be given as soon as possible. If more than 4 days have passed, that dose is skipped and the next one is taken on the regular day. The weekly injection day can also be changed as long as two doses are at least 3 days (72 hours) apart.
What is the maintenance dose of tirzepatide after weight loss?
The label names three maintenance doses for weight management: 5 mg, 10 mg, or 15 mg once weekly. In the SURMOUNT-MAINTAIN trial published in The Lancet in 2026, people who stayed on their maximum tolerated dose were down 21.9% at 112 weeks, those who stepped down to 5 mg were down 16.6%, and those who stopped were down 9.9%. Stepping down to 5 mg kept most of the loss; stopping gave most of it back.
Is the dose of Zepbound® the same as Mounjaro®?
They are the same medicine, tirzepatide, with the same 2.5 mg start, the same 2.5 mg steps, and the same 15 mg adult maximum, but they are approved for different uses. Zepbound® is approved for weight management and for moderate to severe obstructive sleep apnea in adults with obesity. Mounjaro® is approved for type 2 diabetes, including in children aged 10 and older, where the maximum is 10 mg weekly. The two should never be used together, or with any other GLP-1 medicine.
Conclusion
Tirzepatide dosing is a patient, stepwise process: a 2.5 mg start, 2.5 mg increases no closer together than four weeks, a 15 mg ceiling, and three maintenance doses to choose between. The 2026 additions — a four-dose KwikPen®, a clearer picture of what happens at maintenance, and a revised safety section — make the conversation with patients more concrete than it was a year ago, not more complicated.
For providers building or refining a weight management program, IAPAM’s GLP-1 certification training for medical weight management providers covers titration protocols, patient selection, side-effect management, and the business foundations behind them, with AMA PRA Category 1 CME credit online. Many providers pair it with IAPAM’s Botox® training to build a broader cash-pay practice.
Disclaimer: This guide is for informational and educational purposes only and does not constitute medical advice. Dosing must be individualized by a qualified, licensed prescriber, and patients should follow the plan set by their own healthcare team. Always follow current product labeling, your scope of practice, and your state medical and nursing board regulations.
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Disclaimer: The information provided here is for general knowledge only and should not be considered medical advice. For any questions or concerns about your health or medications, please consult your physician or healthcare provider. They are best equipped to provide guidance specific to your medical needs.
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