Peptide Reconstitution Chart: BAC Water, Concentration and Syringe Units by Vial Size
There is one calculation standing between reading about a peptide protocol and actually running it, and it trips up almost everyone the first time. The research says a dose in micrograms. The vial is labelled in milligrams. The syringe is marked in units. Three different scales, none of which convert to the others without knowing one number you choose yourself: how much bacteriostatic water you added.
This page is that arithmetic, worked out in full. Find your vial size, find the water volume you used, read off the concentration - then find how many units that makes your dose. No dose here is a recommendation; the tables answer "if your dose is X, draw Y", and the dose itself is yours to establish with your own research and a qualified practitioner.
The only two formulas you need
Everything below comes from two lines of arithmetic.
Concentration is the vial's contents divided by the water you added. A 10mg vial in 2ml of bacteriostatic water gives 5mg per ml, which is 5,000mcg per ml:
- concentration (mcg/ml) = vial mg × 1000 ÷ ml of water
Units convert that concentration to a mark on the syringe. A U-100 insulin syringe is graduated so that 100 units = 1ml. So:
- units to draw = dose in mcg ÷ concentration × 100
The key thing to understand - and the part that confuses people - is that the water volume does not change your dose. It changes how big the draw is. More water means a more dilute solution and a larger, easier-to-read mark on the syringe. Less water means a smaller, fiddlier one. The amount of peptide entering you is identical either way.
Concentration by vial size and water volume
Find your vial down the left, the water you added across the top. The cell is your concentration in micrograms per millilitre.
| Vial size | 1ml BAC | 2ml BAC | 3ml BAC | 5ml BAC |
|---|---|---|---|---|
| 2mg | 2,000 mcg/ml | 1,000 mcg/ml | 666.7 mcg/ml | 400 mcg/ml |
| 5mg | 5,000 mcg/ml | 2,500 mcg/ml | 1,666.7 mcg/ml | 1,000 mcg/ml |
| 10mg | 10,000 mcg/ml | 5,000 mcg/ml | 3,333.3 mcg/ml | 2,000 mcg/ml |
| 15mg | 15,000 mcg/ml | 7,500 mcg/ml | 5,000 mcg/ml | 3,000 mcg/ml |
| 20mg | 20,000 mcg/ml | 10,000 mcg/ml | 6,666.7 mcg/ml | 4,000 mcg/ml |
| 30mg | 30,000 mcg/ml | 15,000 mcg/ml | 10,000 mcg/ml | 6,000 mcg/ml |
| 40mg | 40,000 mcg/ml | 20,000 mcg/ml | 13,333.3 mcg/ml | 8,000 mcg/ml |
| 50mg | 50,000 mcg/ml | 25,000 mcg/ml | 16,666.7 mcg/ml | 10,000 mcg/ml |
| 70mg | 70,000 mcg/ml | 35,000 mcg/ml | 23,333.3 mcg/ml | 14,000 mcg/ml |
| 80mg | 80,000 mcg/ml | 40,000 mcg/ml | 26,666.7 mcg/ml | 16,000 mcg/ml |
Aevum's calculator defaults to 3ml, deliberately. For someone new to measuring their own doses, a more dilute mix is the safer default: the draws are bigger, the markings easier to read, and a small misread costs proportionally less.
Units to draw, at 3ml of bacteriostatic water
Using the 3ml default, here is what each dose works out to on a U-100 syringe. A dash means the draw would exceed a 1ml syringe - reconstitute in less water, or split the dose.
| Vial size | 100mcg | 250mcg | 500mcg | 1mg | 2mg | 3mg | 5mg |
|---|---|---|---|---|---|---|---|
| 2mg | 15 | 37.5 | 75 | - | - | - | - |
| 5mg | 6 | 15 | 30 | 60 | - | - | - |
| 10mg | 3 | 7.5 | 15 | 30 | 60 | 90 | - |
| 15mg | 2 | 5 | 10 | 20 | 40 | 60 | 100 |
| 20mg | 1.5 | 3.8 | 7.5 | 15 | 30 | 45 | 75 |
| 30mg | 1 | 2.5 | 5 | 10 | 20 | 30 | 50 |
| 40mg | 0.8 | 1.9 | 3.8 | 7.5 | 15 | 22.5 | 37.5 |
| 50mg | 0.6 | 1.5 | 3 | 6 | 12 | 18 | 30 |
| 70mg | 0.4 | 1.1 | 2.1 | 4.3 | 8.6 | 12.9 | 21.4 |
| 80mg | 0.4 | 0.9 | 1.9 | 3.8 | 7.5 | 11.2 | 18.8 |
If you used a different water volume, scale it: at 2ml every number here becomes two-thirds of what it shows; at 5ml, multiply by five-thirds. Or skip the mental arithmetic and put your own numbers into the dosing calculator, which does this and also tells you how many vials a run of a given length will need.
Worked example
Say you have a 10mg vial and your intended dose is 3mg once weekly.
- You add 2ml of bacteriostatic water. Concentration = 10 × 1000 ÷ 2 = 5,000 mcg/ml.
- Your dose is 3mg, which is 3,000mcg.
- Units = 3,000 ÷ 5,000 × 100 = 60 units.
So you draw to the 60 mark. The vial holds 10mg total and you are using 3mg per dose, so it covers three doses with a little left over - which is how you get from a dose to a shopping list. Over a 16-week run at one dose a week, that is 48mg, or five 10mg vials.
Concentrations for the compounds in the index
The same arithmetic applied to actual vial sizes, in mcg/ml. Where a compound is sold in several sizes, the figure below is for the vial named.
| Compound | Vial | At 2ml | At 3ml | At 5ml |
|---|---|---|---|---|
| Oxytocin 2mg | 2mg | 1,000 | 666.7 | 400 |
| AOD9604 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Ipamorelin 5mg + CJC-1295 No DAC 5mg Blend | 5mg | 2,500 | 1,666.7 | 1,000 |
| BPC-157 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| DSIP 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Kisspeptin 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Selank 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Semaglutide 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Semax 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Sermorelin 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| SLU-PP-332 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Thymosin A1 5mg | 5mg | 2,500 | 1,666.7 | 1,000 |
| Tirz 5mg (Tirzepatide/Mounjaro) | 5mg | 2,500 | 1,666.7 | 1,000 |
| CJC-1295 (no DAC) 10mg | 10mg | 5,000 | 3,333.3 | 2,000 |
| Ipamorelin 10mg | 10mg | 5,000 | 3,333.3 | 2,000 |
| KPV 10mg | 10mg | 5,000 | 3,333.3 | 2,000 |
| Melanotan 2 10mg | 10mg | 5,000 | 3,333.3 | 2,000 |
| PT-141 10mg | 10mg | 5,000 | 3,333.3 | 2,000 |
Every one of these has a component page with its published dosing outline. Read that before setting a number - the arithmetic on this page tells you how to hit a dose accurately, not what the dose should be.
Where the arithmetic goes wrong
Four mistakes account for most of them.
- Confusing mg and mcg. 1mg is 1,000mcg. A tenfold slip here is the single most common and most consequential error in peptide dosing.
- Assuming the water volume sets the dose. It does not. It sets the concentration. Two people running the same protocol with different water volumes draw different unit marks and receive the same dose.
- Reading a U-40 syringe as U-100. U-40 syringes exist (largely veterinary) and are graduated differently. If your syringe does not say U-100, the unit conversion above does not apply.
- Recalculating from memory after a re-mix. If you reconstitute a second vial with a different water volume, every unit figure changes. Write the volume on the vial.
Frequently asked
How much bacteriostatic water should I add to a 10mg vial?
Whatever volume you choose - it changes the concentration, not the dose. 1ml gives 10,000mcg/ml, 2ml gives 5,000mcg/ml, 3ml gives roughly 3,333mcg/ml and 5ml gives 2,000mcg/ml. More water produces a larger, easier-to-read draw on the syringe, which is why 3ml is a common default for people new to measuring doses.
How many units is 250mcg on a U-100 insulin syringe?
It depends entirely on the concentration. At 3,333mcg/ml (a 10mg vial in 3ml) it is 7.5 units. At 5,000mcg/ml (the same vial in 2ml) it is 5 units. The formula is dose in mcg divided by concentration in mcg/ml, multiplied by 100.
Does adding more bacteriostatic water make the peptide weaker?
It makes the solution more dilute, but not the dose weaker. You draw proportionally more of the dilute solution to deliver the same amount of peptide. The only practical effects are that the draw is larger and easier to measure accurately, and the vial contains more total liquid.
Can I use sterile water or saline instead of bacteriostatic water?
Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what makes a multi-dose vial safe to draw from repeatedly over days or weeks. Plain sterile water and saline have no preservative and are intended for single use.
How do I work out how many vials I need for a full run?
Multiply your dose by the number of doses per week and by the number of weeks, then divide by the vial size. A 3mg weekly dose over 16 weeks is 48mg total, which needs five 10mg vials. The Aevum calculator does this automatically once you set dose, frequency and duration.
Build a structured protocol from your goal, with vial maths worked out — then talk it through with our concierge, Jenny.
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