Peptide Reconstitution & Dosing Calculator
Enter your vial strength, the bacteriostatic water, and your prescribed dose. Get the exact units to draw on an insulin syringe, the concentration, and how many doses the vial holds.
Your vial
The milligrams printed on the vial (e.g. 5, 10, 15).
How much water goes into the vial to dissolve the peptide.
1 mg = 1000 mcg. Your provider sets this number.
Draw this much
Pull to
10units
0.100 mL on a U-100 syringe
- Concentration
- 2.50 mg/mL
- Per unit
- 25 mcg
- Doses per vial
- 20
- Dose volume
- 0.100 mL
Educational tool, not a prescription. Your RxPepsDirect peptides arrive pre-reconstituted and ready to use, so most patients only need the "units" number above. A licensed provider sets your actual dose during intake.
Or skip the mixing entirely
If you are running these numbers, you are exactly who RxPepsDirect is for. Get the same peptides without ever touching a vial of bacteriostatic water.
- Comes ready to use, pre-reconstituted in the vial
- No bacteriostatic water to buy, no mixing, no guesswork
- Prescribed by a licensed provider in your state
- Filled by Optimal Balance Pharmacy, a licensed 503A compounding pharmacy in the United States
One $39 provider review. No subscriptions, no markup on the medication.
How the math works
Reconstituting a peptide is just dilution. You dissolve a known amount of dry peptide (in milligrams) into a known volume of bacteriostatic water (in milliliters). That gives you a concentration, and from the concentration you can convert any prescribed dose into a volume, then into insulin-syringe units.
The three formulas the calculator uses:
- Concentration = peptide (mg) divided by water (mL). A 10 mg vial in 2 mL of water is 5 mg/mL.
- Dose volume = your dose (mg) divided by the concentration. A 0.25 mg dose at 5 mg/mL is 0.05 mL.
- Units = dose volume (mL) times 100, because a U-100 insulin syringe has 100 units per mL. 0.05 mL is 5 units.
Reconstitution, step by step
You will not need this for RxPepsDirect peptides, which ship pre-reconstituted. It is here because it is the most-asked peptide question, and because it explains what the numbers above represent.
- Let the vial reach room temperature so the powder dissolves cleanly.
- Draw your bacteriostatic water into a syringe, then push it slowly down the inside wall of the peptide vial. Do not aim the stream directly at the powder.
- Swirl gently to dissolve. Do not shake. Peptides are fragile and foaming can degrade them.
- Store the reconstituted vial in the refrigerator, out of light, and never frozen. See how to store peptide solutions for peptide-specific shelf life.
Where RxPepsDirect fits
RxPepsDirect prescriptions are written by licensed providers in 28 states and filled by Optimal Balance Pharmacy, a 503A pharmacy that ships every peptide pre-reconstituted and ready to use. That means you skip the mixing and usually only need the "units" number this calculator gives you. Pricing is simple: a one-time $39 provider review, then the pharmacy bills the medication at wholesale.
New to this? Start with how to give a subcutaneous injection, or browse the full peptide selection to see what your provider can prescribe.
Peptide calculator FAQ
- How do I use this peptide calculator?
- Enter three numbers: the milligrams of peptide in your vial, the amount of bacteriostatic water you added (or that the pharmacy added), and your prescribed dose. The calculator returns the exact number of units to pull on a U-100 insulin syringe, the concentration, and how many doses the vial holds.
- Do RxPepsDirect peptides come already mixed?
- Yes. RxPepsDirect peptides are compounded and shipped pre-reconstituted by Optimal Balance Pharmacy, so they arrive ready to use. You do not add water yourself. For our patients this calculator is mainly a check on how many units to draw for a prescribed dose.
- How much bacteriostatic water should I add when reconstituting?
- There is no single correct amount. More water makes small doses easier to measure but increases the volume you inject. Most protocols use 1 to 3 mL per vial. Change the water figure in the calculator to see how it shifts the units you draw.
- What is bacteriostatic water?
- Bacteriostatic water is sterile water that contains 0.9 percent benzyl alcohol as a preservative. The preservative lets you draw from a multi-dose vial repeatedly over its shelf life. It is different from plain sterile water, which has no preservative.
- How do I read units on an insulin syringe?
- A standard U-100 insulin syringe is marked in units, where 100 units equals 1 mL. The calculator gives you the exact unit line to pull to. A 30-unit (0.3 mL) syringe suits small doses, a 100-unit (1.0 mL) syringe suits larger ones.
- How long does a reconstituted peptide last?
- Once mixed, most peptides are stable refrigerated for a period of weeks, though it varies by peptide. Keep the vial cold, out of light, and do not freeze it. See the guide on how to store peptide solutions for peptide-specific timelines.
- Can this tool tell me what dose to take?
- No. This is an educational conversion tool, not medical advice. A licensed provider sets your dose based on your goals, labs, and history. The calculator only converts a dose your provider prescribed into the units to draw.
- Why does concentration matter?
- Concentration decides how many units each dose takes and whether it fits your syringe. The same 250 mcg dose is a different number of units in a strong vial versus a dilute one. Matching concentration to your dose keeps the draw easy to measure.