Guide · Updated August 2026
Tirzepatide Dosage Chart: How Many Units Is Each mg?
"How many units is 5mg of tirzepatide?" has no single answer. It depends entirely on the concentration printed on your vial, which varies by pharmacy. Brand-name Mounjaro and Zepbound pens never require this math at all. This guide covers the FDA-approved dosing schedule, the conversion formula for compounded vials, and a chart across the concentrations pharmacies commonly use. Checked against current pharmacy and manufacturer sources, August 2026.
Why “Units” Comes Up at All
Mounjaro and Zepbound ship as pre-filled, single-dose pens. You click the pen, it delivers a fixed amount, and there is no syringe, no draw, and no unit to calculate. If you are on a brand pen, this entire conversion question does not apply to you.
The “units” question comes almost entirely from compounded tirzepatide, which is dispensed differently: as a multi-dose vial that you draw from yourself using a small insulin syringe. Compounded tirzepatide is not FDA-approved and is not a generic version of Mounjaro or Zepbound. It is a copy of the active ingredient mixed by a compounding pharmacy, and because pharmacies mix it at different strengths, the same prescribed dose can look like a completely different number of units depending on which vial is in your fridge.
This page is a reference for understanding that math, not a substitute for the dosing instructions your prescriber and pharmacy gave you. If the number you calculate does not match what is printed on your pharmacy label, trust the label and call the pharmacy before you draw anything up.
I have been on brand Mounjaro since 2024, so I have never had to draw a dose myself. But readers ask me this question constantly, usually after switching pharmacies or comparing notes with someone else on the same mg dose who reports a completely different unit count. The mismatch is almost always the concentration, not an error.
The FDA-Approved Dose Levels
Whether a person is on brand tirzepatide or a compounded version, prescribers generally follow the same six-step dose ladder that Eli Lilly established in the Mounjaro and Zepbound prescribing information: start low, hold for at least 4 weeks, then step up.
| Dose | Typical Minimum Duration | Status |
|---|---|---|
| 2.5 mg | 4 weeks | Starting dose, not intended to be therapeutic |
| 5 mg | 4 weeks | First therapeutic dose |
| 7.5 mg | 4 weeks | Titration step |
| 10 mg | 4 weeks | Titration step |
| 12.5 mg | 4 weeks | Titration step |
| 15 mg | Ongoing | Maximum FDA-approved dose |
Our Mounjaro dosage titration guide covers what each of these steps feels like in practice, dose by dose. This page is only about converting the mg number on your prescription into a units number on a syringe, for the vials where that step is necessary.
The Conversion Formula
Compounded tirzepatide vials are drawn up with a standard U-100 insulin syringe, where the barrel is marked in units and 100 units always equals 1 mL, regardless of what is dissolved in that milliliter. The concentration on your vial label (in mg per mL) is what turns a units mark into a specific dose.
Units = (Prescribed dose in mg ÷ Vial concentration in mg/mL) × 100
Two examples make the point:
- A 5 mg dose drawn from a 10 mg/mL vial: (5 ÷ 10) × 100 = 50 units
- The same 5 mg dose drawn from a 20 mg/mL vial: (5 ÷ 20) × 100 = 25 units
Same prescription, same 5 mg, half the number on the syringe. Neither number is wrong. They are two different concentrations delivering the same dose. This is exactly why a units chart copied from a forum post or a different pharmacy’s website can lead someone to draw the wrong amount.
Before you draw anything: Check the concentration (mg/mL) printed on your specific vial label. Compounding pharmacies do not use a single industry-standard concentration. If your pharmacy's instructions and the chart below disagree, the pharmacy's label is correct, not this page.
Units by Common Concentration
Compounding pharmacies typically mix tirzepatide somewhere in the 5 to 30 mg/mL range, and some pharmacies pick a concentration specifically so their patients’ doses land on clean, easy-to-read numbers. The table below shows the math for concentrations reported across compounding pharmacies. Use it to sanity-check your own label, not to replace it.
| Prescribed Dose | 5 mg/mL | 10 mg/mL | 12.5 mg/mL | 20 mg/mL | 30 mg/mL |
|---|---|---|---|---|---|
| 2.5 mg | 50 units | 25 units | 20 units | 12.5 units | 8.3 units |
| 5 mg | 100 units | 50 units | 40 units | 25 units | 16.7 units |
| 7.5 mg | 150 units* | 75 units | 60 units | 37.5 units | 25 units |
| 10 mg | 200 units* | 100 units | 80 units | 50 units | 33.3 units |
| 12.5 mg | 250 units* | 125 units* | 100 units | 62.5 units | 41.7 units |
| 15 mg | 300 units* | 150 units* | 120 units* | 75 units | 50 units |
*Exceeds the 100-unit capacity of a standard 1 mL (100-unit) insulin syringe. A dose marked with an asterisk means either the concentration is too dilute for that dose to fit in one syringe, or your pharmacy uses a larger syringe or a different draw method. This is a sign to call your pharmacy, not a math error to work around yourself.
Notice that fractional units (8.3, 16.7, 33.3, 41.7) show up at the 30 mg/mL concentration. Standard insulin syringes are marked in whole-unit or half-unit increments, not tenths. If your calculation lands on a fraction, your pharmacy has either rounded it in your instructions or chosen a different concentration for your specific dose. A fraction you cannot see marked on your syringe is a reason to call the pharmacy, not a reason to estimate.
Comparing tirzepatide pricing across providers?
See current cash-pay pricing for brand and compounded tirzepatide across telehealth providers.
Check Yucca Health →Syringe Sizes and Why They Matter
Insulin syringes come in three common sizes, and picking the wrong one makes small doses hard to read accurately:
| Syringe Size | Total Units | Best For |
|---|---|---|
| 0.3 mL (30-unit) | 30 units | Small doses, marked in 1-unit increments, easiest to read precisely at low volumes |
| 0.5 mL (50-unit) | 50 units | Mid-range doses |
| 1 mL (100-unit) | 100 units | Larger doses, coarser gradations that make small doses harder to measure precisely |
A 12.5-unit dose drawn on a 100-unit syringe is a short, hard-to-read line near the bottom of the barrel. The same 12.5-unit dose drawn on a 30-unit syringe fills almost half the barrel and is much easier to measure accurately. Ask your pharmacy which syringe size ships with your specific concentration and dose, and use that one rather than whatever insulin syringe you may have on hand from another prescription.
Common Mistakes People Make
Using a chart from a different pharmacy. The most common error is applying a units chart found online to a vial from a pharmacy that mixes at a different concentration. Always match the chart to the exact mg/mL printed on your label.
Assuming Mounjaro’s dose steps require conversion. They do not. Every FDA-approved Mounjaro and Zepbound pen delivers a fixed, pre-measured dose. If you are on brand medication, none of this math applies to you.
Confusing mL with units. A 0.5 mL draw is not the same as “50 units” unless the syringe is a 1 mL/100-unit syringe, where 0.5 mL happens to equal 50 units. On a different-sized syringe, the same volume reads differently. Read the unit markings on the barrel, not the mL markings.
Rounding aggressively. A fractional unit result is a signal to call the pharmacy, not a cue to round to the nearest whole number on your own. Compounding pharmacies that use uneven concentrations usually provide written, dose-specific draw instructions for exactly this reason.
FAQ
How many units is 5mg of tirzepatide?
It depends entirely on your vial’s concentration. At 10 mg/mL, 5 mg is 50 units. At 20 mg/mL, the same 5 mg is 25 units. There is no single correct answer without knowing the mg/mL printed on your specific vial.
Why don’t Mounjaro or Zepbound require unit conversion?
Brand-name Mounjaro and Zepbound are dispensed as pre-filled, single-dose auto-injector pens. Eli Lilly manufactures each pen to deliver one fixed dose per click. There is no syringe to draw and no concentration math involved. Unit conversion is only relevant for compounded tirzepatide dispensed in multi-dose vials.
Is compounded tirzepatide the same as Mounjaro or Zepbound?
No. Compounded tirzepatide is not FDA-approved and is not a generic version of Mounjaro or Zepbound. It is prepared by a compounding pharmacy using the same active ingredient, but it has not gone through FDA review for safety, effectiveness, or manufacturing quality the way the brand products have. Whether a compounded product is appropriate for a given patient is a decision for a licensed prescriber, not something this chart determines.
What if my calculated dose comes out to a fraction of a unit?
Call your pharmacy before drawing anything. A fractional result usually means the concentration on your vial does not divide evenly into your prescribed dose, and your pharmacy should have already given you rounded, dose-specific instructions. Do not estimate a fractional unit by eye on the syringe.
What syringe size should I use for compounded tirzepatide?
Whatever size your pharmacy ships with your prescription. As a general rule, smaller doses are easier to measure accurately on a smaller-capacity syringe (0.3 mL or 0.5 mL) because the unit markings are spaced further apart. A 1 mL syringe is better suited to larger-volume draws.
This guide is for general information only, not medical advice, and does not tell you what dose to take or how to administer it. Compounded tirzepatide is not FDA-approved and is not a generic version of Mounjaro or Zepbound. Only a licensed prescriber and your dispensing pharmacy can tell you the correct dose and draw volume for your specific prescription. Full details in our disclaimer.
Related
Guides:
- Mounjaro Dosage Titration: 2.5mg to 15mg
- Mounjaro Dosage Guide
- Compounded vs Brand-Name GLP-1
- Cheapest Tirzepatide Online
Medications: Compounded Tirzepatide · Mounjaro · Zepbound
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