Peptide reconstitution calculator.
Convert vial size, bacteriostatic water, and dose into exact U-100 syringe units, concentration, and draws per vial — or work backwards from a clean syringe mark to the water volume that produces it. Presets pre-fill the figures for every AKH BioLabs compound.
250 mcg = 0.25 mg
- Concentration
- 5 mg/ml
- Draws per vial
- 40
Reconstitution summary — custom vial Vial: 10 mg Bacteriostatic water: 2 ml Dose per draw: 250 mcg Concentration: 5 mg/ml Draw: 5 units (U-100) Draws per vial: 40 Laboratory arithmetic only. Not a dosing recommendation. All products are supplied strictly for research use and are not for human consumption.
For research and laboratory use only. Not for human consumption.
Three formulas, no black box.
Every figure the calculator produces can be checked by hand.
vial content ÷ water volume
10 mg ÷ 2 ml = 5 mg/ml
dose ÷ concentration
0.25 mg ÷ 5 mg/ml = 0.05 ml
draw volume × 100
0.05 ml × 100 = 5 units
Worked example: a 10 mg vial reconstituted with 2 ml of bacteriostatic water gives 5 mg/ml. A 250 mcg draw is then 0.05 ml — 5 units on a U-100 insulin syringe — and the vial holds 40 such draws.
| Vial | Water | Concentration | 250 mcg draw | 500 mcg draw |
|---|---|---|---|---|
| 5 mg | 1 ml | 5 mg/ml | 5 units | 10 units |
| 5 mg | 2 ml | 2.5 mg/ml | 10 units | 20 units |
| 5 mg | 3 ml | 1.67 mg/ml | 15 units | 30 units |
| 10 mg | 1 ml | 10 mg/ml | 2.5 units | 5 units |
| 10 mg | 2 ml | 5 mg/ml | 5 units | 10 units |
| 10 mg | 3 ml | 3.33 mg/ml | 7.5 units | 15 units |
Water sets concentration, not amount.
The volume of bacteriostatic water added to a vial does not change how much compound the vial contains. It changes only how concentrated the resulting solution is, and therefore how many syringe units a given draw occupies. A 10 mg vial holds 10 mg whether it is reconstituted with 1 ml or 5 ml.
That makes the choice a practical one about readability. Too little water and a draw lands on 2 or 3 units, where a small error in reading the plunger is a large proportional error in the amount drawn. Too much water and the draw exceeds the 100-unit barrel, requiring more than one draw. Laboratory practice generally targets the middle of the barrel, roughly the 10 to 50 unit region, where a misread of one unit is a small fraction of the total.
The reverse mode of the calculator above inverts the arithmetic: given a target draw and a preferred syringe mark, it returns the water volume that produces it. That is usually a faster route to a clean number than trying volumes until one lands well.
Vials quantified in International Units, such as somatropin, HCG and HMG, follow the same logic with IU in place of milligrams. Because IU measures biological activity rather than mass, the calculator never converts between IU and milligrams for those products.
What changes once the powder dissolves.
Lyophilised peptide and reconstituted peptide are two different stability problems.
Lyophilised powder
Freeze-dried peptide is comparatively robust. With water removed, the hydrolysis and oxidation pathways that degrade peptides in solution are largely inactive, which is why lyophilised material tolerates ambient temperatures in transit and is held frozen for long-term storage.
In solution
Once water is added the clock starts. Reconstituted peptide is kept refrigerated at 2-8 degrees Celsius and protected from light. Stability windows differ by compound, and the figure for each is stated on that compound's own product page rather than generalised here.
Bacteriostatic, not sterile
Bacteriostatic water contains roughly 0.9% benzyl alcohol, which suppresses microbial growth and is what makes a multi-draw vial viable. Sterile water carries no preservative, so a vial reconstituted with it is a single-use preparation.
Handling that costs potency
Agitation denatures peptides, so vials are swirled rather than shaken and the water stream is aimed at the glass wall instead of directly onto the powder. Repeated freeze-thaw cycling and prolonged light exposure are the other two common causes of avoidable loss.
Purity at the point of manufacture is a separate question from stability in storage, and one is not evidence of the other. Each product's Certificate, from a named outside laboratory, is published on its product page. What actually degrades a peptide goes through the chemistry in full, and how laboratory verification works explains what those reports measure.
Four recurring mistakes.
- 01
Confusing units with volume
Syringe units measure volume, not peptide mass. The same 10-unit mark holds twice as much compound at 5 mg/ml as it does at 2.5 mg/ml. A unit figure means nothing without the concentration that produced it.
- 02
Mixing mg and mcg
One milligram is 1,000 micrograms. A factor-of-1,000 slip is the most common error in this calculation, which is why every dose on this page is echoed in both units.
- 03
Assuming more water means less compound
Adding more bacteriostatic water dilutes the solution but removes nothing from the vial. The same total remains; each draw simply occupies more volume.
- 04
Treating IU as a mass unit
International Units express biological activity, and the IU-to-milligram relationship differs by preparation. There is no general conversion factor, and this calculator does not offer one.
Every vial in the catalog.
Vial strength and the reconstitution volume each compound is presented with in the calculator above, with the published literature for each alongside.
Preset volumes are the figure each compound is most commonly reconstituted with in the published protocols, not a recommendation. The calculator accepts any volume.
Common questions.
For research and laboratory use only. Not for human consumption. Figures produced by this tool are laboratory arithmetic — they are not medical advice, dosing instructions, or a recommendation of any kind.