What is tirzepatide?
A tirzepatide dosage chart only makes sense once you know what the vial holds. Tirzepatide, developed by Eli Lilly under the code LY3298176, is a 39-amino-acid peptide that acts on two receptors: GIP and GLP-1. That dual action is what separates it from semaglutide, which targets GLP-1 only. Like semaglutide, it carries a fatty acid side chain that helps it last longer in the body.
The approved products come as ready-to-use injections labeled in mg. Research-labeled tirzepatide is usually freeze-dried powder in vials that run much larger than most peptides: 10 mg, 15 mg, 30 mg and even 60 mg. Those larger vials change the math in ways worth understanding before you read any chart.
How much BAC water for a tirzepatide vial?
No single volume is correct. The water only sets the concentration. With tirzepatide the vial sizes span a wide range, so the same water volume produces very different strengths. The chart below shows mcg per unit for the four common vial sizes across several water volumes.
| BAC water | 10 mg vial | 15 mg vial | 30 mg vial | 60 mg vial |
|---|---|---|---|---|
| 1 mL | 100 mcg/unit 10 mg/mL | 150 mcg/unit 15 mg/mL | 300 mcg/unit 30 mg/mL | 600 mcg/unit 60 mg/mL |
| 2 mL | 50 mcg/unit 5 mg/mL | 75 mcg/unit 7.5 mg/mL | 150 mcg/unit 15 mg/mL | 300 mcg/unit 30 mg/mL |
| 3 mL | 33.33 mcg/unit 3.333 mg/mL | 50 mcg/unit 5 mg/mL | 100 mcg/unit 10 mg/mL | 200 mcg/unit 20 mg/mL |
| 5 mL | 20 mcg/unit 2 mg/mL | 30 mcg/unit 3 mg/mL | 60 mcg/unit 6 mg/mL | 120 mcg/unit 12 mg/mL |
Each cell shows mcg per unit on a U-100 syringe (100 units = 1 mL) and the resulting concentration.
Read down a column to follow one vial, such as a tirzepatide 30mg reconstitution, as more water is added. Read across a row to see how a tirzepatide 10mg vial compares with a 60 mg vial at the same volume: the larger vial is six times as concentrated, so the same amount needs one sixth of the units. Every cell is vial mg × 1,000 ÷ (water mL × 100). The BAC water to peptide ratio guide explains the relationship in more depth.
Worked example: tirzepatide reconstitution math
Here is the tirzepatide calculator in action. For example, if the amount you already have is 3 mg and a 30 mg vial is mixed with 3 mL of BAC water:
The math: 30 mg ÷ 3 mL = 10 mg/mL (10,000 mcg/mL), which is 100 mcg per unit. 3 mg ÷ 10,000 mcg/mL = 0.3 mL = 30 units on a U-100 syringe.
Now keep the amount and the water the same but switch to a 60 mg vial. For example, if the amount you already have is 3 mg and a 60 mg vial is mixed with 3 mL:
The math: 60 mg ÷ 3 mL = 20 mg/mL (20,000 mcg/mL), which is 200 mcg per unit. 3 mg ÷ 20,000 mcg/mL = 0.15 mL = 15 units on a U-100 syringe.
Doubling the vial at the same water volume doubles the concentration and halves the units. With very large vials, small syringe marks carry a lot of peptide, so reading the syringe accurately matters more. If you want to confirm any result by hand, the guide to checking calculator math walks through it.
Tirzepatide dosage chart: what the numbers mean
This tirzepatide dosage chart is a conversion table. Each cell says how many mcg are in one U-100 unit for a given vial and water volume. It does not say what amount to use, how often, or for how long. For the approved products those decisions come from labeling and a qualified professional, and no calculator can replace that.
The same logic answers “tirzepatide units to mg”. Divide units by 100 to get mL, then multiply by the concentration (vial mg ÷ water mL). Because 100 units always equal 1 mL on a U-100 syringe, the volume side never changes; only the mg per unit does. Also keep mg and mcg straight: 1 mg is 1,000 mcg, and a mix-up gives an answer off by a factor of a thousand.
One more check is worth building into the habit. Before trusting any tirzepatide calculator result, confirm that the vial size you entered matches the label in your hand. Tirzepatide is sold in so many sizes that entering 10 mg for a 30 mg vial is an easy slip, and it changes every number on the page by the same factor. The chart only reflects the inputs it is given.
Tirzepatide reconstitution notes for large vials
Some suppliers specify bacteriostatic water as the diluent, adding it slowly down the inside of the vial and swirling gently, and refrigerating after mixing. These are labeling statements, not instructions from this site. Two practical points matter more with tirzepatide than with smaller peptides. First, a vial has a physical capacity, so the water volume you can add is limited by the vial itself, not just by the math. Second, a large vial takes longer to use, and a punctured multi-dose vial of BAC water is commonly dated and discarded within 28 days unless the manufacturer states otherwise. See BAC water vial sizes to match the diluent vial to your use.
Is tirzepatide FDA-approved?
Yes, as specific branded products. Tirzepatide is FDA-approved as Mounjaro (2022) and Zepbound (2023), both made by Eli Lilly. Research-labeled vials are not those products, and a correct calculation cannot confirm their identity, purity, sterility or content. For Lilly’s investigational triple agonist, see the retatrutide calculator.
Tirzepatide FAQ
How much BAC water do you add to a 30 mg tirzepatide vial?
There is no single required volume. The water only sets the concentration. The chart on this page shows mcg per unit for several volumes; the product labeling decides the diluent and volume.
How do I convert tirzepatide units to mg?
Divide the units by 100 to get mL, then multiply by the concentration, which is the vial mg divided by the mL of water added. The result changes with every vial size and water volume.
Why does a 60 mg tirzepatide vial need fewer units?
At the same water volume, a 60 mg vial is more concentrated than a 10, 15 or 30 mg vial, so the same amount fits in fewer units on the syringe.
Is this a tirzepatide dosage calculator?
It converts an amount you already have into mL and U-100 syringe units. It does not recommend a dose, schedule or treatment.
Are tirzepatide vials the same as Mounjaro or Zepbound?
No. Mounjaro and Zepbound are FDA-approved Eli Lilly products supplied ready to use. Research-labeled vials are different products.