Tirzepatide Dosage Chart: mg to Units by Vial Concentration
Tirzepatide dosage chart from the Zepbound prescribing information, 2.5 mg to 15 mg, plus a mg to units table for common compounded vial strengths.
By Juan Montes
Updated October 19, 2026 · 8 min read
PrescribedRX is a telehealth platform; prescriptions are written by licensed clinicians and filled by licensed partner pharmacies.
Short answer: In the Zepbound prescribing information, tirzepatide (Zepbound, Mounjaro) starts at 2.5 mg once a week and can go up in 2.5 mg steps no sooner than every 4 weeks, to a maximum of 15 mg. This tirzepatide dosage chart also converts mg to units: on a U-100 insulin syringe, 2.5 mg is 25 units if your vial is 10 mg/mL, but 50 units at 5 mg/mL and 12.5 units at 20 mg/mL. Branded pens are dosed in mg, so units only matter for compounded tirzepatide vials.
This page is a reference, not dosing instructions. Your provider sets your dose, and your pharmacy label tells you your vial’s concentration. The dose steps below come from the Zepbound prescribing information (revised 02/2026).
What is the tirzepatide dosage chart in the prescribing information?
The Zepbound prescribing information starts everyone at 2.5 mg once weekly for 4 weeks. After at least 4 weeks on a dose, the dose can go up by 2.5 mg, and the most anyone takes is 15 mg a week (Zepbound prescribing information). If every step were taken on the earliest possible week, it would look like this:
| Weeks (earliest possible) | Weekly dose | What the prescribing information says about it |
|---|---|---|
| Weeks 1 to 4 | 2.5 mg | Starting dose only, not a maintenance dose |
| Weeks 5 to 8 | 5 mg | A weight-reduction maintenance dose |
| Weeks 9 to 12 | 7.5 mg | A step on the way up |
| Weeks 13 to 16 | 10 mg | A maintenance dose (weight reduction or sleep apnea) |
| Weeks 17 to 20 | 12.5 mg | A step on the way up |
| Week 21 onward | 15 mg | Maximum dose; a maintenance dose (weight reduction or sleep apnea) |
Reference only. Your provider sets the dose; check your pharmacy label for concentration.
Two things the chart can hide. First, the prescribing information describes 2.5 mg as a starting dose, not a maintenance dose. The current prescribing information lists 5, 10 or 15 mg once weekly as the maintenance doses for weight reduction, and 10 or 15 mg for obstructive sleep apnea. Second, the timeline is a minimum, not a schedule. Steps happen no sooner than every 4 weeks, and the prescribing information ties them to tolerability (Zepbound prescribing information).
Mounjaro is the same molecule with the same 2.5 mg start and the same 15 mg maximum for adults. Its prescribing information covers type 2 diabetes, not weight loss, and notes the 2.5 mg dose is for starting treatment and is “not intended for glycemic control” (Mounjaro prescribing information).
How many units is 2.5 mg of tirzepatide?
It depends on how strong your vial is. On a standard U-100 insulin syringe, 2.5 mg of tirzepatide is 25 units (0.25 mL) at 10 mg/mL, 50 units (0.50 mL) at 5 mg/mL, 12.5 units at 20 mg/mL and 10 units at 25 mg/mL. There is no single right number until you know the mg/mL on your label.
You can check any number yourself with two simple formulas:
- mL to draw = dose in mg ÷ concentration in mg/mL
- Units on a U-100 syringe = (dose in mg ÷ concentration in mg/mL) × 100
Example: 2.5 mg ÷ 10 mg/mL = 0.25 mL, and 0.25 × 100 = 25 units. Our vial-to-syringe units calculator does the same math for any vial strength.
Tirzepatide mg to units chart by concentration
Find your mg/mL on the pharmacy label first. Don’t assume 10 mg/mL. The number of units for a given mg dose changes with the vial’s concentration. Each cell shows units on a U-100 syringe, with mL in brackets.
Lower-strength vials (5 to 12.5 mg/mL)
| Dose | 5 mg/mL | 8 mg/mL | 10 mg/mL | 12.5 mg/mL |
|---|---|---|---|---|
| 2.5 mg | 50 (0.50) | 31.3 (0.31) | 25 (0.25) | 20 (0.20) |
| 5 mg | 100 (1.00) | 62.5 (0.63) | 50 (0.50) | 40 (0.40) |
| 7.5 mg | 150 (1.50)* | 93.8 (0.94) | 75 (0.75) | 60 (0.60) |
| 10 mg | 200 (2.00)* | 125 (1.25)* | 100 (1.00) | 80 (0.80) |
| 12.5 mg | 250 (2.50)* | 156.3 (1.56)* | 125 (1.25)* | 100 (1.00) |
| 15 mg | 300 (3.00)* | 187.5 (1.88)* | 150 (1.50)* | 120 (1.20)* |
Higher-strength vials (15 to 30 mg/mL)
| Dose | 15 mg/mL | 17 mg/mL | 20 mg/mL | 25 mg/mL | 30 mg/mL |
|---|---|---|---|---|---|
| 2.5 mg | 16.7 (0.17) | 14.7 (0.15) | 12.5 (0.13) | 10 (0.10) | 8.3 (0.08) |
| 5 mg | 33.3 (0.33) | 29.4 (0.29) | 25 (0.25) | 20 (0.20) | 16.7 (0.17) |
| 7.5 mg | 50 (0.50) | 44.1 (0.44) | 37.5 (0.38) | 30 (0.30) | 25 (0.25) |
| 10 mg | 66.7 (0.67) | 58.8 (0.59) | 50 (0.50) | 40 (0.40) | 33.3 (0.33) |
| 12.5 mg | 83.3 (0.83) | 73.5 (0.74) | 62.5 (0.63) | 50 (0.50) | 41.7 (0.42) |
| 15 mg | 100 (1.00) | 88.2 (0.88) | 75 (0.75) | 60 (0.60) | 50 (0.50) |
*More than 100 units will not fit in one 1 mL U-100 syringe. These cells show why higher doses are usually supplied in stronger vials. Values are rounded to one decimal place for units and two for mL. Reference only. Your provider sets the dose; check your pharmacy label for concentration.
Why do compounded tirzepatide vials come in different strengths?
There is no single standard compounded vial. Each pharmacy decides its own strength and vial size, so two people on the same mg dose can draw very different unit amounts. If your pharmacy changes, or your vial strength changes, recheck the math before your next dose.
Are Zepbound pens measured in units?
No. Branded Zepbound is dosed in mg, and there is no unit math. The single-dose pens and vials each hold one dose, from 2.5 mg to 15 mg in 0.5 mL. The newer multi-dose KwikPen and multi-dose vial hold 2.4 mL with four 0.6 mL doses, at strengths from 10 mg to 60 mg per 2.4 mL (Zepbound prescribing information). People using Mounjaro vials need a 1 mL syringe that can measure the labeled volume (Mounjaro prescribing information).
What dosing mistakes happen with units and mL?
Mix-ups between mL, mg and units have been reported with compounded GLP-1 vials. A poison control center case series described three patients using compounded semaglutide, two of whom self-administered 10-fold dosing errors, and one who dosed in milliliters and units rather than milligrams. The authors noted that vials, unlike prefilled pens, allow large dosing errors (Lambson et al., J Am Pharm Assoc 2023).
The most common traps:
- Mixing up mL and units. On a U-100 syringe, 1 unit is 0.01 mL. Reading 0.25 mL as 25 mL, or 25 units as 2.5, is a 10x or 100x error.
- Using a chart built for someone else’s vial. A unit count copied from a forum or another clinic only works if the concentration matches yours.
- Not checking the syringe size. Insulin syringes come in 0.3, 0.5 and 1 mL sizes, so the markings are spaced differently.
- Doses above 100 units. Anything over 100 units is more than 1 mL and will not fit in one standard 1 mL syringe. Ask your pharmacy or provider rather than guessing.
If a number on your label, your provider’s note and a chart do not match, talk to your provider or pharmacy before the next dose.
How fast do you move up a tirzepatide dose?
The prescribing information says no sooner than every 4 weeks, and only as tolerated (Zepbound prescribing information). Your provider decides whether you stay, step up or step down.
What should I do if I miss a dose of tirzepatide?
The prescribing information says a missed dose should be taken as soon as possible within 4 days (96 hours), and that if more than 4 days have passed, the missed dose should be skipped and the next dose taken on the usual day. It says two doses should be at least 3 days (72 hours) apart (Zepbound prescribing information). If you have missed several weeks, talk to your provider before restarting. Our help page on missed doses and restarting a GLP-1 covers what to tell your care team.
What weight loss did each dose show in SURMOUNT-1?
SURMOUNT-1 was the main 72-week trial of branded tirzepatide in adults with obesity or overweight (Jastreboff et al., NEJM 2022). Results by dose, as reported in the Zepbound prescribing information (Table 2):
| Group | Average weight change at 72 weeks | Share who lost at least 15% |
|---|---|---|
| Tirzepatide 5 mg | -15.0% | 48.0% |
| Tirzepatide 10 mg | -19.5% | 66.6% |
| Tirzepatide 15 mg | -20.9% | 70.6% |
| Placebo | -3.1% | 8.8% |
These are averages from a clinical trial of the branded drug. They are not a promise of what any one person will lose, and they come from Zepbound, not a compounded product. If you want to see how these numbers compare with semaglutide, read our tirzepatide vs semaglutide trial comparison.
Which side effects mean you should call your provider?
For general education, the Zepbound prescribing information lists stomach effects such as nausea, diarrhea, vomiting and constipation as the most common side effects (Zepbound prescribing information; DailyMed, Zepbound). Our page on tirzepatide side effects goes through them in detail, and our tirzepatide safety information page covers more. If you notice any symptom that worries you, contact your provider or get medical help.
How does tirzepatide dosing work with PrescribedRX?
You start with a short online eligibility check. A licensed provider reviews your answers, typically within 48 hours, and decides whether compounded tirzepatide is appropriate for you. If it is prescribed, a licensed partner pharmacy fills it, and it ships with free priority shipping in plain packaging. Compounded medications are prepared by licensed pharmacies and are not FDA-approved. Availability varies by state, and it is self-pay with no insurance.
Your provider sets your starting dose and decides when, or whether, to step it up. Each plan includes a three-month supply, needles, syringes and alcohol swabs, and portal messaging with your care team for dosing questions. The price is the same at every dose:
- Compounded tirzepatide: 3 month plan $597 · $199/mo · Billed every 3 months. Cancel anytime.
Because vial strength can vary, always read the concentration on the pharmacy label that comes with your order, and use the matching column in the chart above. To see how the plan price works out against other options, read what tirzepatide costs.
Tirzepatide dosage FAQ
How many units is 5 mg of tirzepatide?
On a U-100 syringe, 5 mg is 50 units (0.50 mL) at 10 mg/mL, 100 units (1.00 mL) at 5 mg/mL, 25 units at 20 mg/mL and 20 units at 25 mg/mL. The number changes with every concentration, so check your vial label and use the chart above. Your provider sets the dose.
Do I need to reach 15 mg?
The Zepbound prescribing information lists 5 mg, 10 mg and 15 mg as maintenance doses for weight reduction, with 15 mg as the maximum. It says dose increases happen no sooner than every 4 weeks and only as tolerated (Zepbound prescribing information). Your provider sets the dose.
How do I know when to increase my tirzepatide dose?
The prescribing information allows a 2.5 mg increase after at least 4 weeks on the current dose, if it is tolerated (Zepbound prescribing information). Your provider sets the dose and may keep it the same, step it up or step it down. Talk to your provider before changing anything.
How many units is 2.5 mg in a 30, 50 or 100 unit syringe?
The syringe size does not change the unit count. One unit is 0.01 mL on any U-100 syringe, whether it holds 30, 50 or 100 units. What changes the count is your vial: 2.5 mg is 25 units at 10 mg/mL and 12.5 units at 20 mg/mL.
Check your eligibility for tirzepatide
Start with a short eligibility check. A licensed provider decides whether it is appropriate for you, and your provider sets the dose. 3 month plan $597 · $199/mo · Billed every 3 months. Cancel anytime. See the compounded tirzepatide plan, take the eligibility quiz, or browse all GLP-1 weight loss treatment options.
Related reading: tirzepatide results by timepoint · do GLP-1 medications cause fatigue?
Sources
- Eli Lilly and Company. Zepbound (tirzepatide) Prescribing Information, revised 02/2026. prescribing information PDF. Accessed Oct 2026.
- Eli Lilly and Company. Mounjaro (tirzepatide) Prescribing Information, revised 01/2026. prescribing information PDF. Accessed Oct 2026.
- DailyMed. Zepbound (tirzepatide) injection prescribing information. National Library of Medicine, NIH. dailymed.nlm.nih.gov. Accessed Oct 2026.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. PubMed. Accessed Oct 2026.
- Lambson JE, Flegal SC, Johnson AR. Administration errors of compounded semaglutide reported to a poison control center: case series. J Am Pharm Assoc. 2023;63(5):1643-1645. PubMed. Accessed Oct 2026.
This article is for general information. It is not medical advice and it is not a recommendation for any particular treatment. Whether a treatment is appropriate for you is a decision for a licensed clinician who has reviewed your health history and current medications.
About the author
Juan MontesJuan Montes writes and reviews PrescribedRX's clinical content, covering testosterone replacement therapy, men's sexual health, weight management and hair loss. He trained as a Professional Nurse at the Colombian Red Cross in Cali, Colombia, and has worked in healthcare since 2011, roughly six of those years in direct emergency and critical care nursing. He served as Head Nurse in Emergency…
More from Juan →This article is for information only and is not medical advice. Treatment is prescribed solely at the discretion of a licensed provider following a clinical evaluation.
