Enter your vial amount and desired dose to instantly calculate how many units to draw on your syringe. Works for any reconstituted peptide or premixed medication.
We'll tell you how much bacteriostatic water to add so each dose lands on this mark.
What liquid volume should I use?
Common choice: 1–3 mL. Most vials hold a max of ~3 mL.
• Less water → smaller injections, but harder to measure precisely
• More water → easier measurement, but larger injection volume
Always use bacteriostatic water (not saline or plain water) to preserve the peptide.
2
Concentration
mg/mL
Listed on your vial or prescription (e.g. testosterone cypionate = 200 mg/mL)
3
Desired Dose per Injection
How much medication per injection
4Total Vial Volume (optional - to calculate total doses)
mL
Results
Draw to this line on your syringe
-
units
0
⚠️ Overflow - dose exceeds syringe capacity. Use a larger syringe or increase liquid volume.
⚠️ Desired dose exceeds the available medication in the vial.
Concentration
-
Total doses in vial
-
Per-dose breakdown
-
Syringe Type
30-unit insulin syringes are most common for peptides
Enter your values above
Fill in the medication amount and desired dose to see your results.
Educational use only. This calculator is for informational purposes and does not constitute medical advice. Always verify dosing with your healthcare provider. Measurement errors can have serious health consequences - double-check your calculations.
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Log doses, rotate injection sites, forecast testosterone & GLP-1 levels, and get smart reminders - all on-device, no cloud required.
Reconstitute if you have a powder vial you'll mix with bacteriostatic water. Premixed if the medication already comes in liquid form.
2
Enter medication amount
For reconstitution: enter the mg amount printed on your vial (e.g., "5 mg BPC-157"). For premixed: enter the concentration listed (e.g., "200 mg/mL testosterone cypionate").
3
Enter your desired dose
Enter the dose you plan to inject each time (in mg or mcg).
4
Set water, or set your target units (reconstitution only)
Choose Set water → get units to enter how much bacteriostatic water you'll add and see the units to draw. Or flip to Set units → get water to pick a clean number of syringe units and have the calculator tell you how much water to add. 1–2 mL is common for most peptides.
Peptide & GLP-1 Reconstitution Chart
Common reconstitution setups and the units to draw on a U-100 insulin syringe (100 units = 1 mL). These are worked examples; use the calculator above for your exact vial and dose.
Compound
Vial
BAC water
Concentration
Example dose
Draw to (units)
Semaglutide
5 mg
1 mL
5 mg/mL
0.25 mg
5 units
Semaglutide
5 mg
1 mL
5 mg/mL
0.5 mg
10 units
Semaglutide
10 mg
2 mL
5 mg/mL
1 mg
20 units
Tirzepatide
10 mg
1 mL
10 mg/mL
2.5 mg
25 units
Tirzepatide
20 mg
1 mL
20 mg/mL
5 mg
25 units
Tirzepatide
30 mg
1.5 mL
20 mg/mL
7.5 mg
37.5 units
Retatrutide
10 mg
1 mL
10 mg/mL
2 mg
20 units
Retatrutide
20 mg
2 mL
10 mg/mL
4 mg
40 units
BPC-157
5 mg
2 mL
2.5 mg/mL
250 mcg
10 units
TB-500
5 mg
2.5 mL
2 mg/mL
2 mg
100 units
Educational reference only, not medical advice or a recommended dose. Confirm your protocol with a licensed provider. Store reconstituted vials refrigerated and follow compound-specific discard windows.
Frequently Asked Questions
What is reconstitution?
Reconstitution means dissolving a freeze-dried (lyophilized) powder peptide into liquid - usually bacteriostatic water - to create an injectable solution. Most research peptides (BPC-157, TB-500, CJC-1295, etc.) come as powder and must be reconstituted before injection.
What does "units" mean on a syringe?
Insulin syringes measure in "units" - specifically insulin units. 100 units = 1 mL. So 10 units = 0.10 mL, 25 units = 0.25 mL. When you use an insulin syringe for peptides, you draw to the unit marking that corresponds to your calculated volume.
How much bacteriostatic water should I add?
Most practitioners use 1–2 mL for standard 5 mg peptide vials. Use this calculator to find the liquid volume that gives you an easy-to-measure number of units. For example, adding 2 mL to a 5 mg BPC-157 vial gives 2.5 mg/mL concentration. A 250 mcg dose = 10 units on a 30-unit syringe - a clean, easy measurement.
What syringe should I use?
30-unit (0.3 mL) insulin syringes are most commonly used for peptides. They allow precise measurement in small increments. 50-unit and 100-unit syringes are options if your dose requires a larger volume. Always use a fresh, sterile needle for each injection.
Can I use this for semaglutide / GLP-1 medications?
Yes - select Premixed mode and enter your concentration (e.g., 2.5 mg/mL or 5 mg/mL for compounded semaglutide, 2 mg/0.5 mL = 4 mg/mL for tirzepatide). Then enter your dose in mg. The calculator will give you the units to draw.
How do you reconstitute tirzepatide?
Add bacteriostatic water to the powder vial, then draw your dose with a U-100 insulin syringe. For a 10 mg tirzepatide vial, adding 1 mL of bacteriostatic water gives a 10 mg/mL solution, so a 2.5 mg dose is 0.25 mL, or 25 units. For a 20 mg vial with 1 mL of water (20 mg/mL), a 5 mg dose is 25 units. Inject the water slowly down the vial wall, swirl gently rather than shaking, and store the reconstituted vial refrigerated.
How do you reconstitute semaglutide?
Add bacteriostatic water to the powder vial and draw your dose on a U-100 insulin syringe. A 5 mg semaglutide vial with 1 mL of bacteriostatic water gives 5 mg/mL, so a 0.25 mg starting dose is 5 units and a 0.5 mg dose is 10 units. Add the water slowly, swirl gently instead of shaking, and keep the reconstituted vial refrigerated.
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