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Peptide reconstitution calculator

Vial size, bacteriostatic water, your dose — the exact draw in insulin-syringe units. The same calculator that ships inside PeptideLab.

Your syringe (U-100 insulin)
10203040500.10.30.520
Vial size
mg
BAC water
ml
2.50 mg/ml · 1u = 25 mcg
Dose per injection
Draw to
20 units
0.20 ml

Clean, measurable draw

From your 5 mg vial at 2 ml, you can dose 10× at 500 mcg.

This vial

10
doses of 500 mcg

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peptidelabapp.com/calculator?vial=5&water=2&dose=500&syr=0.5

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Reconstitution
Compound
5 mg vial
Draw
20u
Clean draw
Vial5 mg
BAC water2 ml
Concentration2.50 mg/ml
Dose500 mcg
Syringe0.5 ml · U-100
Doses per vial~10
Draw volume
0.20 ml
peptidelabapp.com
Your biology. Your data. Your call.

In the app

Stop re-deriving this every week

  • Save it as a protocol — the draw is on every dose you log
  • Track the vial: doses left, discard window, when to reorder
  • Reminders, injection-site rotation, bloodwork trends
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Reconstitution, explained

What is peptide reconstitution?+

Peptides ship as a lyophilized (freeze-dried) powder. Reconstitution is dissolving that powder in bacteriostatic water so it can be measured and drawn. How much water you add sets the concentration, and the concentration is what decides how many units on an insulin syringe equal your dose.

How many units is my dose?+

Divide the vial mass by the water volume to get the concentration in mg/ml. Divide your dose by that concentration to get the volume of one injection in ml. On a U-100 insulin syringe every 0.01 ml is one unit, so multiply that volume by 100. The calculator does exactly this and shows both steps.

How much bacteriostatic water should I add?+

More water gives larger, easier-to-measure draws; less water gives smaller draws that fit smaller barrels. 2 ml is the most common choice for a 5–10 mg vial. Pick the amount whose draw lands comfortably on your syringe's scale — the fit line under the result says when a draw is too fine to measure or too big for the barrel.

What does U-100 mean?+

U-100 is the standard insulin syringe: 100 units per millilitre. It is what the units on the barrel are calibrated to. If you have a U-40 or U-500 barrel (rare, mostly veterinary), the unit markings mean something different and this calculator's unit readout will not apply.

Which peptides does it work for?+

Any lyophilized peptide — the math is the same regardless of the compound. The picker lists 74 of the most common ones (GLP-1s like semaglutide, tirzepatide and retatrutide, growth-hormone peptides, healing peptides like BPC-157 and TB-500, and more) purely to label the calculation. Selecting one never changes your numbers.

Does this give medical advice?+

No. It performs arithmetic on numbers you enter. It does not recommend a dose, a compound, or a protocol, and it never pre-fills a dose for you. For medical decisions, consult a qualified healthcare professional.

For informational purposes only. This tool performs mathematical calculations and does not provide medical advice. Consult a healthcare professional for medical decisions. PeptideLab for iPhone.