Reconstitution Calculator — Peptide mg/mL & Syringe UnitsReconstitution Calculator — Peptide mg/mL & Syringe UnitsQuick peptide reconstitution calculator. Enter vial mg and BAC water, get mg/mL and exact insulin units per dose in seconds. Free, no sign-up needed.
Turn any peptide vial into an exact insulin-syringe draw. Enter the vial size, how much bacteriostatic water you're adding, and your target dose. We'll show mg/mL, the units to draw on a U-100 or U-40 syringe, and total doses per vial.
This is a unit converter. It converts an amount you already have into volume and syringe units. It does not tell you what to take, and it is educational only — not medical advice. Confirm every amount with your clinician and your product label.
Example mixes to try the converter
Calculator inputs
Total peptide in the vial.
Volume of bacteriostatic water you reconstitute with.
Per-injection dose you want to draw.
U-100 = 100 units per mL (standard). U-40 = 40 units per mL.
Syringe previewU-100
0.0u
0100-unit barrel
Enter vial size, BAC water and target dose to see the fill mark.
How we handle safety and your data
DoseRoutine is a tracking and reference tool. It does not diagnose, prescribe, or replace your doctor or pharmacist.
Interaction results are informational flags to discuss with a clinician — not clearances to combine anything.
Dose calculators do the arithmetic you enter. They don't decide what you should take, or how much.
First-hand observations from using DoseRoutine day to day. Personal experience, not medical advice.
I stopped doing the math on my phone's calculator
For the first few months I reconstituted vials with a note app and a calculator, and I twice mixed 2 mL into a vial I had planned at 1 mL. Typing the vial strength and bacteriostatic water volume into one screen — and seeing the units-on-the-syringe number instead of a milligram figure — is what actually stopped the errors for me.
Insulin syringe units are the number that matters
The mistake I kept making was converting to mL and then eyeballing the barrel. Now I read the result as syringe units only. On a 1 mL/100-unit syringe, a 10 mg vial in 2 mL gives 5 mg per mL, so a 250 mcg dose is 5 units — a mark I can actually see, instead of a sliver between two lines.
Write the mix date on the vial, not in an app
I log reconstitution in DoseRoutine, but I still write the date on the vial cap with a marker. When I have two vials of the same peptide in the fridge at different concentrations, the physical label is the thing that stops me grabbing the wrong one at 6am.
Related calculators
More free DoseRoutine calculators and dosing references.
Reviewed by the DoseRoutine editorial team. Last reviewed .
Frequently asked questions
What does the reconstitution calculator do?
It converts a peptide vial's strength and the bacteriostatic water you add into a concentration in mg/mL, then converts your target dose into the exact insulin syringe units to draw on a U-100 or U-40 syringe, plus how many doses the vial holds in total.
How is the concentration calculated?
Concentration in mg/mL equals the total peptide in the vial divided by the milliliters of bacteriostatic water added. For example, a 5 mg vial reconstituted with 2 mL of water gives a concentration of 2.5 mg/mL.
How do syringe units get calculated from my dose?
The calculator first converts your dose to milligrams, divides by the concentration to get the volume in mL, then multiplies by 100 for a U-100 syringe or 40 for a U-40 syringe. It also warns you when a dose would need more volume than a single full syringe.
Does the calculator work for compounds other than BPC-157?
Yes. It works for any peptide reconstituted with bacteriostatic water — the built-in presets cover BPC-157, TB-500, semaglutide, tirzepatide, ipamorelin and CJC-1295, and the vial size, water volume, dose and syringe type fields can be set to any values.
Is this calculator free and does it store my numbers?
It's free, needs no account, and runs entirely in your browser. Nothing you enter is saved unless you choose to save a result to a signed-in DoseRoutine account, which also lets you track doses remaining and get injection reminders.
Does this calculator tell me what dose to take?
No. It only converts an amount you already have — from a prescriber or a protocol you're following — into a syringe reading. It is an educational tool, not medical advice; always verify dosing with your prescriber.
What reconstitution actually is
A lyophilized peptide arrives as a dry powder with a stated mass in milligrams. Reconstitution is the step where you add a measured volume of bacteriostatic water to that vial, turning a mass into a concentration — milligrams per milliliter — that a syringe can measure. The powder itself contributes almost no volume, which is why the diluent volume you choose is effectively the volume of the finished vial.
One formula covers every case: concentration equals the milligrams in the vial divided by the milliliters of water you add. Everything else — units on an insulin syringe, doses per vial, how long the vial lasts — falls out of that single number.
Choosing a dilution you can measure
There is no single correct volume. A more concentrated mix means smaller draws and fewer milliliters in the fridge; a more dilute mix means larger, easier-to-read draws at the cost of vial space. The practical rule is to pick the dilution that puts your usual dose somewhere you can read confidently on the syringe you own — for most people on a 100-unit insulin syringe, that means a draw in the ten-to-forty unit range rather than down at three or four units.
Insulin syringe units are a volume measure, not a dose measure. One hundred units is one milliliter, so a unit is a hundredth of a milliliter regardless of what is dissolved in it. This is the conversion that produces most tenfold errors, because a protocol quoted in units only means anything alongside the concentration it assumed.
Concentration (mg/mL) = vial milligrams ÷ milliliters of bacteriostatic water
Units to draw = (dose in mg ÷ concentration) × 100
100 units on an insulin syringe = 1 mL, whatever the concentration
Recalculate from scratch whenever the vial size or diluent volume changes
Handling the vial after mixing
Add the water slowly down the side wall of the vial rather than directly onto the powder, and let it dissolve on its own instead of shaking. Once mixed, the vial belongs in the fridge, and its useful life is measured in weeks rather than months — bacteriostatic water contains a preservative that allows repeated entry, but it does not make the contents indefinitely stable.
Note the date you mixed it. The most common reason a vial gets discarded early is nobody remembering when it was reconstituted, and the most common reason one gets used too long is the same uncertainty in the other direction. Saving the mix against the vial in the app records the concentration and the date together and counts down the remaining doses as you log them.
Track this in your own routine
Build your stack, get reminders at the right times, and see combination notes across 475+ supplements, hormones and peptides. Free to start — no card needed.