How to Reconstitute Tirzepatide: Mixing Guide and Reconstitution Chart

If you've been handed a vial of tirzepatide powder and a separate bottle of liquid, you've probably realized this isn't the same experience as clicking a pen. There's mixing involved. There's math involved. And there's a nagging voice asking, "What if I get this wrong?"

That voice is worth listening to. Mixing and measuring errors with compounded GLP-1 vials are common enough that the FDA has issued warnings about them. The good news is that the process itself is straightforward once you understand what's happening, and the math is the same every time.

This guide covers how to reconstitute tirzepatide step by step, a chart showing what different water volumes do to each vial size, and how to turn "mg" into "units" on your syringe. It won't tell you what dose to take. That comes from your prescriber.

First: Most Tirzepatide Doesn't Need Mixing at All

Here's something that surprises a lot of people. The FDA-approved tirzepatide products, Mounjaro (for type 2 diabetes) and Zepbound (for weight management and obstructive sleep apnea), don't need reconstitution. According to the Zepbound prescribing information on DailyMed, every Zepbound presentation, whether single-dose pen, single-dose vial, multi-dose vial, or KwikPen, is a ready-to-use solution. There's no powder and nothing to add.

So if you're using a brand-name pen or vial, you can skip this guide. Follow the instructions that came with it.

This guide is for compounded tirzepatide that arrives as a lyophilized (freeze-dried) powder. Two important points about that. First, compounded drugs aren't FDA-approved, and the FDA notes they don't go through its review for safety, effectiveness, or quality (FDA's concerns with unapproved GLP-1 drugs). Second, the rules changed after the tirzepatide shortage ended. FDA declared the shortage resolved in December 2024, and its grace periods for pharmacies making copies ended in early 2025 (FDA compounding policy update). A licensed pharmacy may still compound tirzepatide for an individual patient in limited circumstances, but mass-produced copies are no longer permitted.

What does that mean for you? Get tirzepatide only through a licensed prescriber and a licensed pharmacy. Products sold online as "research peptides" or "not for human consumption" are a different category entirely, and the FDA has warned companies selling them. We don't recommend them.

One more thing: many pharmacy-compounded vials arrive as a liquid that's already mixed. If your vial is liquid, don't add anything to it. Only reconstitute a vial that's clearly labelled as powder, using the diluent and volume your pharmacy specifies.

What You'll Need

Lay out everything before you begin. You'll need the tirzepatide vial, the diluent your pharmacy provided or specified (usually bacteriostatic water, which is sterile water with a preservative for multi-dose use; see the DailyMed label), alcohol swabs, a sterile syringe for adding the diluent, U-100 insulin syringes for your doses, and a sharps container.

About that mixing syringe. A 1 mL insulin syringe holds 100 units, which is exactly 1 mL. If your label says to add 2 or 3 mL, you'll either draw multiple times with the same sterile syringe or use a 3 mL syringe for this one step. Whichever you use, it must be new and sterile.

How to Reconstitute Tirzepatide Step by Step

Read through all six steps before you start. It takes about five minutes once you've done it once or twice.

Step 1: Prep your space. Wash your hands with soap and water, and wipe down a clean, flat surface. If the vial has been in the fridge, let it sit for a few minutes so it's closer to room temperature.

Step 2: Swab the stoppers. Flip the caps off both vials. Wipe each rubber stopper with a fresh alcohol swab and let it air dry completely. Wet alcohol can be pushed into the vial by the needle.

Step 3: Draw the diluent. Pull the plunger back to the volume your pharmacy specified, filling the syringe with air. Inject that air into the diluent vial, flip it upside down, and draw the liquid. Tap out any large bubbles.

Step 4: Add it slowly down the side. Insert the needle into the tirzepatide vial at an angle so the liquid runs down the inside wall of the glass. Push the plunger slowly. Think of pouring a fizzy drink down the side of a tilted glass. A fast stream straight onto the powder causes foaming.

Step 5: Swirl gently. Remove the needle and gently swirl the vial or roll it between your palms. Don't shake it. The powder should dissolve within a minute or two. If some clings to the glass, let it sit in the fridge for a few minutes and swirl again.

Step 6: Inspect and label. The solution should be clear and colourless with no particles. Write the concentration and today's date on the vial. That label is what keeps you safe every time you draw a dose afterwards.

Tirzepatide Reconstitution Chart

This is the main reference. For each common vial size, it shows the concentration you get with different diluent volumes, how many units on a U-100 insulin syringe equal 1 mg, and how much tirzepatide sits in 10 units (0.1 mL).

The "units per 1 mg" column is the one to focus on. Multiply it by the number of milligrams your prescriber told you, and you have your units. The last column works as a quick sanity check: it tells you roughly how much is in a small, easy-to-see amount on the syringe.

Notice what happens with bigger vials. A 60mg vial with 1 mL of diluent is so concentrated that a single unit on the syringe holds a large amount of drug, and a tiny misread becomes a big error. That's why pharmacies often specify more diluent for larger vials. The right volume is whatever is on your pharmacy label.

How Much Reconstitution Solution for 10mg, 15mg, or 30mg Tirzepatide?

This is one of the most searched questions about tirzepatide, and the honest answer is: use the volume on your pharmacy label or the one your prescriber gave you. There isn't one universal number.

What the chart shows is that the water volume doesn't change how much tirzepatide is in the vial. It only changes how concentrated each unit is. For example, a 15mg vial with 3 mL of diluent gives 5 mg/mL. A 30mg vial with 3 mL gives 10 mg/mL, so 10 units equals 1 mg. A 60mg vial with 3 mL means 5 units equals 1 mg.

If you don't have instructions, don't guess. Call the pharmacy. This is exactly the kind of question they expect.

Worked Example: Turning mg Into Units

Let's walk through one example so the chart makes sense. The dose here is purely for the math, not a recommendation.

If your prescriber told you 2.5 mg and you have a 10mg vial that was mixed with 2 mL of bacteriostatic water:

The concentration is 10 mg ÷ 2 mL = 5 mg/mL. To get 2.5 mg, you need 2.5 ÷ 5 = 0.5 mL. On a U-100 syringe, 1 mL is 100 units, so 0.5 mL is 50 units. You can also get there from the chart: 20 units per mg × 2.5 mg = 50 units.

Here's why the diluent volume matters so much. If that same 10mg vial had been mixed with only 1 mL, the concentration would be 10 mg/mL and the same 2.5 mg would be just 25 units. Same prescription, half the units. This is exactly how people end up taking double or half their intended dose: they switch vials or pharmacies and keep drawing the same number of units out of habit.

Also check that the result fits your syringe. 50 units won't fit in a 0.3 mL (30 unit) syringe, so you'd need a 0.5 mL or 1 mL syringe for that example. The FDA has specifically recommended that patients get a syringe appropriate for their dose and be shown how to measure it (FDA alert on dosing errors).

If you'd rather not do this by hand, the tirzepatide calculator does it in seconds. Enter your vial size, the diluent you added, and your prescribed dose, and it shows the units to draw.

The Mistake the FDA Keeps Warning About

It's worth spelling this out because it's the single most important safety point in this guide. The FDA has received reports of people drawing 5 to 20 times their intended dose of compounded GLP-1s. The cause is usually confusion between milligrams, millilitres, and units.

Here's the rule to remember. "Units" on an insulin syringe are a volume marking, not an amount of drug. 10 units is always 0.1 mL. How much tirzepatide is in those 10 units depends entirely on how the vial was mixed. So "take 10 units" only means something if you also know the concentration.

If your instructions only say a number of units, confirm the concentration with your pharmacy. If your instructions only say mg, do the math (or use the calculator) and double-check it before every new vial.

Storing Tirzepatide Before and After Mixing

For brand-name Zepbound, the label is clear: store it in the fridge at 2 to 8°C (36 to 46°F), don't freeze it, and keep it in the carton to protect it from light. If needed, a single-dose pen or vial can be kept unrefrigerated at up to 30°C (86°F) for up to 21 days.

Compounded vials are different, and their storage directions come from the pharmacy, not the FDA label. Before mixing, follow the pharmacy's instructions. Freeze-dried peptides are generally kept cold and away from light.

After mixing, keep the vial in the fridge, upright, away from light, and never frozen. For how long, look for a "beyond-use date" on your pharmacy label and follow it. If there isn't one, a general rule for preserved multi-dose vials from CDC injection safety guidance is to discard them 28 days after first puncture unless the manufacturer or pharmacy says otherwise. When in doubt, ask the pharmacy.

What If It Looks Cloudy?

Reconstituted tirzepatide should be clear. If it's cloudy, hazy, discoloured, or has particles, don't use it. Contact the pharmacy that supplied it. Tiny bubbles or foam on top after mixing are usually just trapped air from adding the liquid too quickly. Let the vial rest upright in the fridge and they should settle. If the liquid underneath stays hazy, treat it as cloudy.

Keeping Your Numbers Straight

Between vial sizes, diluent volumes, titration steps, and weekly schedules, there's a lot to remember. Writing the concentration on the vial is step one. Step two is having a log you trust.

PeptideKit lets you set up your tirzepatide protocol with a weekly schedule, reminds you when your dose is due, and includes a reconstitution calculator so the units you draw match the vial you mixed. You can also journal side effects alongside each dose, which is useful when you talk to your prescriber. If you're working through GI side effects, our guide to managing GLP-1 side effects has practical tips.

Frequently Asked Questions

How do you reconstitute tirzepatide?

Swab both stoppers, draw the diluent volume your pharmacy specified, and inject it slowly down the inside wall of the tirzepatide vial. Gently swirl until the powder dissolves into a clear solution, without shaking. Label the vial with the concentration and date, and store it in the fridge. Brand-name Mounjaro and Zepbound are ready-to-use and never need mixing.

How much reconstitution solution do I add to a 10mg vial of tirzepatide?

Use the volume on your pharmacy label. The volume only changes the concentration, not the amount of drug. With 1 mL a 10mg vial is 10 mg/mL, with 2 mL it's 5 mg/mL, and with 3 mL it's about 3.333 mg/mL. The chart in this guide shows units per mg for each.

How much reconstitution solution for 15mg or 30mg tirzepatide?

Again, follow your pharmacy's instructions. With 3 mL of diluent, a 15mg vial is 5 mg/mL and a 30mg vial is 10 mg/mL. Larger vials are usually mixed with more diluent so that each unit on the syringe isn't too concentrated to measure accurately.

How many units is 1 mg of tirzepatide?

It depends on the concentration of your vial. Divide 100 by the concentration in mg/mL to get units per mg on a U-100 syringe. At 5 mg/mL, 1 mg is 20 units. At 10 mg/mL, 1 mg is 10 units. Always confirm the concentration on your vial label first.

Can I reconstitute tirzepatide at home?

If your prescriber and pharmacy have given you a powdered vial with instructions, yes, that's how it's designed to be used. Work clean, use sterile supplies, add the diluent slowly, and don't shake. If you don't have clear instructions on the diluent and volume, ask the pharmacy before mixing.

Do Mounjaro or Zepbound need to be reconstituted?

No. Mounjaro and Zepbound are FDA-approved and come as ready-to-use solutions in pens or vials. Only compounded tirzepatide supplied as a freeze-dried powder needs reconstitution.

How long does reconstituted tirzepatide last in the fridge?

Follow the beyond-use date on your pharmacy label. Without one, the general rule for preserved multi-dose vials is to discard them 28 days after first puncture unless the manufacturer or pharmacy states otherwise. Keep it at 2 to 8°C and never freeze it.

What should I use to mix tirzepatide?

Use the diluent your pharmacy provided or specified, which is usually bacteriostatic water. Don't substitute tap water, saline, or anything else unless the pharmacy tells you to.

The Bottom Line

Reconstituting tirzepatide is a simple routine: clean setup, slow diluent down the glass, gentle swirl, clear label. The part that deserves your full attention is the math afterwards. Units are volume, not dose, and the same number of units means different amounts of tirzepatide depending on how the vial was mixed.

Stick to a licensed prescriber and pharmacy, follow their volume and storage instructions, and check your numbers every time you start a new vial. For the general technique across other GLP-1s and peptides, see our reconstitution guide for weight loss peptides. The peptide calculator handles the arithmetic, and PeptideKit keeps your doses and vials organized.

Always consult with qualified healthcare professionals before starting any peptide therapy protocol. This information is for educational purposes only and does not constitute medical advice.