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How to reconstitute tirzepatide
Tirzepatide has the widest dose range of any compound on this site: 2.5 mg at the bottom, 15 mg at the top, a sixfold spread. That single fact drives everything about reconstituting it, because no one concentration serves both ends well. Get it wrong at the top of the ladder and your dose physically will not fit in a U-100 syringe. This page has the charts for 10, 15, 20, 30 and 60 mg vials, and tells you which concentration your target dose actually requires.
Concentration = vial mg ÷ water mL. Units = (dose mg ÷ concentration) × 100. The constraint that catches people: a U-100 syringe holds 100 units, which is 1 mL. Any dose needing more than that will not fit. Or skip the arithmetic with the reconstitution calculator.
What you need
- • A lyophilized tirzepatide vial. Compounded vials commonly come as 10, 15, 20, 30 or 60 mg
- • Bacteriostatic water (sterile water with 0.9% benzyl alcohol)
- • A U-100 insulin syringe, plus a 3 mL or 5 mL syringe for adding water to the larger vials
- • Alcohol swabs, clean hands, a clean surface
The steps
Prep. Wash your hands. Swab the rubber stopper of both the compound vial and the bacteriostatic water with alcohol and let them air dry.
Draw your water. Pull the volume you decided on above into a syringe. This number is the single decision that sets everything downstream.
Add it slowly. Insert the needle and let the water run down the inside glass wall, not jetting straight onto the powder. Foam means sheared peptide.
Dissolve gently. Swirl the vial or roll it between your palms. Never shake. Wait until it is completely clear. Cloudiness or floating particles means do not use it.
Draw the dose. Work out your units from the chart above, swab the stopper again, and draw on a U-100 syringe, tapping air bubbles back out.
Label and refrigerate. Write the concentration and the date on the vial. In four weeks you will not remember either.
The chart, by concentration
Because vial sizes vary so much, the useful way to read tirzepatide is by the concentration you end up with rather than by the vial you started from. Find your concentration, read across to your dose:
| Concentration | 2.5 mg | 5 mg | 7.5 mg | 10 mg | 12.5 mg | 15 mg |
|---|---|---|---|---|---|---|
| 5 mg/mL | 50 u | 100 u | 150 u | 200 u | 250 u | 300 u |
| 10 mg/mL | 25 u | 50 u | 75 u | 100 u | 125 u | 150 u |
| 20 mg/mL | 12.5 u | 25 u | 37.5 u | 50 u | 62.5 u | 75 u |
| 30 mg/mL | ~8 u | ~17 u | 25 u | ~33 u | ~42 u | 50 u |
Red = over 100 units, which exceeds a single U-100 syringe. You would have to inject twice, which is a good sign you mixed too dilute.
Getting to those concentrations
And here is which vial and water combination produces each one:
| Vial | + 1 mL | + 1.5 mL | + 2 mL | + 3 mL |
|---|---|---|---|---|
| 10 mg | 10 mg/mL | ~6.7 mg/mL | 5 mg/mL | ~3.3 mg/mL |
| 15 mg | 15 mg/mL | 10 mg/mL | 7.5 mg/mL | 5 mg/mL |
| 20 mg | 20 mg/mL | ~13 mg/mL | 10 mg/mL | ~6.7 mg/mL |
| 30 mg | 30 mg/mL | 20 mg/mL | 15 mg/mL | 10 mg/mL |
| 60 mg | 60 mg/mL | 40 mg/mL | 30 mg/mL | 20 mg/mL |
Match the concentration to where you are on the ladder
The mistake almost everyone makes once is reconstituting for the dose they are on today rather than the dose they are climbing towards. Tirzepatide titration runs 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg over roughly five months, and a vial mixed comfortably for 2.5 mg is unusable by the time you reach 12.5 mg.
A practical rule: 10 mg/mL covers 2.5 through 10 mg and is the right default for anyone in the first half of the ladder. If you are heading for 12.5 or 15 mg, mix at 20 mg/mL instead. A 30 mg vial in 1.5 mL gets you there, keeps a 15 mg dose down to 75 units, and still leaves a 2.5 mg dose at a readable 12.5 units. There is no concentration that is genuinely optimal across the whole range, which is why this is a decision rather than a default.
The 60 mg vials that show up in search deserve a specific warning. Sixty milligrams is four to twenty-four weeks of medication in one container, and its beyond-use date will expire long before you finish it. If you have one, the honest options are to mix it and accept significant waste, or to find a smaller vial.
Storage & beyond-use dating
Roughly 28 days refrigerated at 2-8 °C is the working default once tirzepatide is in solution, the same as the other GLP-1s. At weekly dosing that means about four draws from each mix. Do not freeze it, keep it dark, and get it back in the fridge promptly after each draw. The dry powder is far more stable than the solution, which is the whole argument for mixing a smaller vial more often rather than one large vial once. Details in the peptide storage guide.
Common mistakes
- • Mixing at 5 mg/mL and then titrating up. At 7.5 mg you are already over a full syringe.
- • Reading a chart written for a different vial size. "30 units" means nothing without the mg/mL behind it.
- • Reconstituting a 60 mg vial at a starting dose. It will expire with most of it unused.
- • Assuming tirzepatide and semaglutide charts are interchangeable. The dose ranges differ by roughly sixfold.
- • Splitting an over-100-unit dose across two injections as a routine rather than remixing. It doubles the injection burden and the error surface.
This page covers reconstitution mechanics only. It is not medical advice and not an endorsement of compounded tirzepatide over an approved product. Compounded and research-use-only vials are not quality controlled, so stated strength, purity and sterility can be wrong in ways careful mixing cannot fix. The FDA has specifically flagged dosing errors arising from compounded GLP-1 vials. Decisions about use belong with a licensed clinician.
Skip the arithmetic
OptiPin's free reconstitution calculator takes your vial size, water volume and target dose and returns the exact units, flagging the draws that will not fit a syringe. The app then logs every injection, tracks what is left in the vial and warns you before it runs out or expires. iOS, on-device, no account.
Open the calculatorFrequently asked questions
How much bacteriostatic water for a 30 mg tirzepatide vial?
One and a half millilitres gives 20 mg/mL, which is the most broadly useful choice: it keeps a 15 mg dose at 75 units and a 2.5 mg dose at a still-readable 12.5 units. Three millilitres gives 10 mg/mL, which is fine if you will stay at or below 10 mg but leaves you remixing later.
How much bacteriostatic water for a 60 mg tirzepatide vial?
Three millilitres produces 20 mg/mL and two millilitres produces 30 mg/mL. Both are workable, but the more pressing issue with a 60 mg vial is that it holds far more medication than you can use inside a 28-day beyond-use window. Consider whether a smaller vial is available before mixing it.
How many units is 5 mg of tirzepatide?
At 10 mg/mL it is 50 units on a U-100 syringe. At 20 mg/mL it is 25 units, and at 5 mg/mL it is a full 100 units. The dose in milligrams is fixed by your protocol; the units are entirely a function of how you mixed the vial.
Why does my 15 mg dose not fit in the syringe?
Because you mixed too dilute. A U-100 syringe holds 1 mL, so at 10 mg/mL a 15 mg dose needs 1.5 mL, which is 150 units. Remix at 20 mg/mL or higher and it drops to 75 units. Splitting it across two injections works but is a workaround, not a fix.
Is tirzepatide reconstitution the same as semaglutide?
The procedure is identical but the arithmetic is not. Tirzepatide doses run 2.5 to 15 mg against semaglutide's 0.25 to 2.4 mg, roughly six times higher, so a concentration that suits semaglutide will leave a tirzepatide dose far too large to draw. Never reuse a chart across the two.
Sources & further reading
- Bacteriostatic Water for Injection, USP - DailyMed label (multi-dose diluent basics).
- FDA - concerns with unapproved GLP-1 drugs used for weight loss (compounded-vial dosing errors).
- USP General Chapter <797> - Sterile Compounding (aseptic technique, beyond-use dating).
U-100 syringe: 100 units = 1 mL. Vial strengths and fill volumes vary between suppliers, so always verify the stated strength on your own vial before calculating. This page is educational and is not medical advice.
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