To mix tirzepatide powder, add the exact amount of bacteriostatic water your pharmacy lists, let it run down the inside of the vial, and swirl until clear. Never shake it. The water volume sets the strength in mg/mL. That strength sets how many units you draw. Your pharmacy's instructions control every step. This page explains what they mean. If you are new to the drug, start with our tirzepatide guide.
Key takeaways
- Brand Zepbound and Mounjaro come ready to inject. Only some compounded tirzepatide ships as a freeze-dried (lyophilized) powder that you reconstitute.
- Adding 1 mL of bacteriostatic water to a 10 mg vial gives 10 mg/mL; 2 mL gives 5 mg/mL; 0.5 mL gives 20 mg/mL. The pharmacy chooses the volume, not you.
- Swirl, do not shake. Peptides are fragile, and the pharmacy's directions will say the same.
- After mixing, refrigerate at 2 to 8 C (36 to 46 F), do not freeze, protect from light, and follow the beyond-use date on the pharmacy label.
- Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro.
Tirzepatide powder: what you have and why it needs mixing
Lyophilized means freeze-dried. The pharmacy removes the water so the peptide stays stable during shipping and storage. Before you can inject it, you add sterile water back. The water is bacteriostatic water, which contains a small amount of a preservative so a multi-dose vial can be punctured more than once. Your pharmacy supplies it, or tells you which one to use.
Some pharmacies ship tirzepatide already in solution. If your vial is a liquid, you do not mix anything. Check the label. If it says "for reconstitution" or lists a powder weight in mg without a mg/mL, you have a powder vial.
Tirzepatide mixing instructions, step by step
These steps describe the general method. Your pharmacy's printed instructions take priority wherever they differ.
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Try the BMI Calculator →| Step | What to do | Why |
|---|---|---|
| 1 | Wash your hands and lay out the powder vial, the bacteriostatic water, a sterile syringe, and alcohol swabs on a clean surface. | Reduces contamination. |
| 2 | Read the pharmacy label for the water volume, the resulting mg/mL and the beyond-use date. | These three numbers control everything that follows. |
| 3 | Wipe both rubber stoppers with alcohol and let them dry. | Standard aseptic practice. |
| 4 | Draw the specified water volume into the syringe. | The volume sets the concentration. |
| 5 | Insert the needle into the powder vial and aim the stream at the glass wall, not the powder. Push slowly. | Avoids foaming and damage to the peptide. |
| 6 | Remove the syringe and swirl the vial gently in circles. Do not shake. | Shaking can degrade peptides and creates bubbles. |
| 7 | Wait until the solution is fully clear. Look for particles or cloudiness. | The brand label says not to use a solution with particles or discoloration; apply the same rule. |
| 8 | Write the mixing date and the mg/mL on the vial. Refrigerate. | Beyond-use dating starts at mixing. |
Source: general aseptic technique; storage and inspection rules from the Zepbound and Mounjaro prescribing information; volumes and dates from your pharmacy label.
If you prefer to watch, the reconstitution walkthrough video shows the steps on camera.
How much bacteriostatic water to mix with 5 mg or 10 mg of tirzepatide
The answer depends on the concentration your pharmacy wants you to end up with, which is why the label states a volume. Here is the arithmetic for the three concentrations we use as examples across this site.
| Powder in vial | Water added | Resulting concentration | Units for a 2.5 mg dose | Units for a 5 mg dose |
|---|---|---|---|---|
| 10 mg | 0.5 mL | 20 mg/mL | 12.5 units | 25 units |
| 10 mg | 1 mL | 10 mg/mL | 25 units | 50 units |
| 10 mg | 2 mL | 5 mg/mL | 50 units | 100 units |
| 5 mg | 0.5 mL | 10 mg/mL | 25 units | 50 units |
| 5 mg | 1 mL | 5 mg/mL | 50 units | 100 units |
Source: arithmetic (mg divided by mL equals mg/mL; units equal mL times 100 on a U-100 syringe). Your pharmacy's stated volume controls.
Notice that a 10 mg vial mixed with 1 mL holds four 2.5 mg doses or two 5 mg doses. The vial size limits how many weeks it covers. A larger water volume makes the draws bigger and easier to read, but a 5 mg dose at 5 mg/mL fills a whole 1 mL syringe. Do not change the volume to make the math "nicer" without asking the pharmacy. The dosing calculator guide and the calculator handle the conversion once you know your mg/mL.
Storage after mixing
The brand labels give the clearest storage rules for tirzepatide: refrigerate at 2 to 8 C (36 to 46 F), do not freeze, and protect from light. Brand pens and vials can sit unrefrigerated at up to 30 C (86 F) for up to 21 days. Those numbers are for Zepbound and Mounjaro. A reconstituted compounded vial follows the beyond-use date and temperature directions on the pharmacy label, which can be shorter. If a mixed vial was frozen, left warm longer than the label allows, or turned cloudy, do not use it. Our page on what happens if tirzepatide gets warm goes deeper.
Drawing your dose from the mixed vial
Once mixed, treat the vial like any liquid compounded tirzepatide. Wipe the stopper, draw air equal to your dose into the syringe, inject the air into the vial, turn the vial upside down, and pull back to your unit mark. Check for large bubbles and tap them out. The dose schedule is the labeled one: 2.5 mg once weekly for 4 weeks, then 2.5 mg steps after at least 4 weeks each, to a maximum of 15 mg. Full technique is in how to inject with a syringe.
What this means for compounded tirzepatide
Reconstitution is a compounded-product task. It is one more place where a mistake can change your dose, which is why the pharmacy's label matters more than any web page. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro. FDA has raised concerns about unapproved GLP-1 products, including dosing errors, so use only a vial dispensed under a prescription from a state-licensed pharmacy, with written mixing instructions.
At FormBlends, compounded tirzepatide is $149 for the first month, then $239 a month, or $214 a month with Subscribe & Save. Injection supplies are included and the price is the same at every dose. Medication is compounded by state-licensed 503A compounding pharmacies and shipped cold-chain. See pricing or begin at start.
Frequently Asked Questions
How do I mix tirzepatide?
Add the bacteriostatic water volume printed on your pharmacy label, aiming the stream at the vial wall, then swirl gently until clear. Do not shake. Label the vial with the date and concentration and refrigerate it.
How much bacteriostatic water do I mix with 5 mg of tirzepatide?
Whatever your pharmacy specifies. As arithmetic, 0.5 mL gives 10 mg/mL and 1 mL gives 5 mg/mL. The volume changes your unit count, so use the pharmacy's number and write the resulting mg/mL on the vial.
How much reconstitution solution do I use for 10 mg of tirzepatide?
Again, the pharmacy's stated volume. For example, 1 mL of water in a 10 mg vial makes 10 mg/mL, so a 2.5 mg dose is 25 units. Two mL makes 5 mg/mL and the same dose is 50 units.
Can I shake tirzepatide powder to dissolve it faster?
No. Swirl the vial gently and give it time. Shaking can damage the peptide and creates foam that makes drawing an accurate dose harder.
How long does mixed tirzepatide last in the fridge?
Use the beyond-use date on your pharmacy label; it is set for that specific product. The brand labels allow 21 days unrefrigerated for Zepbound and Mounjaro, but that figure does not apply to a compounded vial you mixed yourself.
What if the mixed solution is cloudy or has particles?
Do not inject it. The brand label tells users not to use tirzepatide that has particles or discoloration, and the same caution applies to a compounded vial. Call the pharmacy that dispensed it.
Sources
- Zepbound (tirzepatide) prescribing information, Eli Lilly via DailyMed, revised 08/2026.
- Mounjaro (tirzepatide) prescribing information, Eli Lilly via DailyMed, revised 08/2026.
- Compounding and the FDA: Questions and Answers, U.S. Food and Drug Administration.
- FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss, U.S. Food and Drug Administration.
- FormBlends pricing, Form Blends LLC, verified September 5, 2026.
Next steps
Convert your mixed concentration to units on the tirzepatide dosage chart, then follow the syringe steps. Browse the tirzepatide hub for every other tirzepatide question. If anything on your label is unclear, talk to the pharmacist or a clinician before you mix. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro; a licensed provider decides whether it is appropriate for you.
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