Peptide calculator
How much bacteriostatic water, how many units on the barrel, how many doses in the vial and how long it lasts. Pick any of the 45 injectable compounds for its defaults, or type your own numbers.
I know the dose I want. How many units do I draw?
Picks sensible defaults — change anything you like.
Optional — gives cost per dose.
Draw to
5 u
0.05 mL · 250 mcg
Concentration
5 mg/mL
50 mcg per unit
Doses per vial
40
Vial lasts
5 weeks 5 days
Draw to 5 units on the barrel.
Reference information only — not medical advice. Most compounds listed here are unapproved research chemicals. Doses are what the literature and the community report, not a recommendation. Bloodwork and a doctor beat a spreadsheet every time.
Mcg per unit — quick reference
What one unit on a U-100 insulin syringe delivers, for the common vial-and-water combinations. One unit is 0.01 mL.
| Vial | + 1 mL water | + 2 mL water | + 3 mL water |
|---|---|---|---|
| 2 mg | 20 mcg / unit2 mg/mL | 10 mcg / unit1 mg/mL | 6.67 mcg / unit0.67 mg/mL |
| 5 mg | 50 mcg / unit5 mg/mL | 25 mcg / unit2.5 mg/mL | 16.7 mcg / unit1.67 mg/mL |
| 10 mg | 100 mcg / unit10 mg/mL | 50 mcg / unit5 mg/mL | 33.3 mcg / unit3.33 mg/mL |
| 15 mg | 150 mcg / unit15 mg/mL | 75 mcg / unit7.5 mg/mL | 50 mcg / unit5 mg/mL |
| 20 mg | 200 mcg / unit20 mg/mL | 100 mcg / unit10 mg/mL | 66.7 mcg / unit6.67 mg/mL |
The maths behind it
Three lines of arithmetic, done in this order:
- Concentration = peptide in the vial ÷ water added. A 10 mg vial in 2 mL is 5 mg/mL.
- Per unit = concentration ÷ 100 (a U-100 unit is 0.01 mL). 5 mg/mL gives 0.05 mg — 50 mcg — per unit.
- Units to draw = dose ÷ per-unit. A 250 mcg dose ÷ 50 mcg is 5 units.
Everything else follows: doses per vial is vial strength ÷ dose, and vial life is doses per vial divided by how often you inject.
Mixing, step by step
- Let the vial reach room temperature — cold glass and cold powder mix badly.
- Alcohol-swab both stoppers and let them dry.
- Draw your bacteriostatic water and inject it slowly down the inside wall of the vial, not straight onto the powder.
- Let it dissolve on its own. Swirl gently if you must. Never shake — peptides are fragile and shear-sensitive.
- Wait until the solution is completely clear. Cloudiness or visible particles means something is wrong.
- Label the vial with the strength, the water volume and the date you mixed it.
- Refrigerate, and keep it out of the light.
Calculator FAQ
How do I work out how many units to draw?+
Divide the vial strength by the water you added to get the concentration in mg/mL. On a U-100 insulin syringe, one unit is 0.01 mL, so one unit delivers concentration ÷ 100 in milligrams. Divide your dose by that number and you have your units. A 10 mg vial in 2 mL is 5 mg/mL, so one unit is 50 mcg and a 250 mcg dose is 5 units.
Does the amount of bacteriostatic water change the dose?+
No. The vial holds a fixed amount of peptide. More water means a weaker solution and more units per dose; less water means a stronger solution and fewer units. The dose only changes if you draw a different volume. Pick a water volume that puts your usual dose somewhere between 10 and 50 units — that is the range an insulin syringe measures accurately.
What is a "unit" on an insulin syringe?+
On a standard U-100 syringe, 100 units equal 1 mL, so one unit is 0.01 mL. U-40 syringes — sold mainly for veterinary insulin — put 40 units in 1 mL, so the same mark holds two and a half times more liquid. Using a U-40 syringe while reading a U-100 chart is one of the most common overdose mistakes people make.
How much bacteriostatic water should I use?+
Whatever makes the arithmetic easy and keeps the draw measurable. 1 mL, 2 mL and 3 mL are the usual choices; 2 mL into a 10 mg vial is the most common default because it makes one unit equal 50 mcg. Most peptide vials will not physically hold more than about 3 mL.
Can I use sterile water instead of bacteriostatic water?+
Sterile water contains no preservative, so a multi-dose vial mixed with it should be treated as single-use or kept for a very short time in the fridge. Bacteriostatic water contains 0.9% benzyl alcohol, which is what makes repeated draws from the same vial reasonable. Some compounds and some people react badly to benzyl alcohol.
How long does a reconstituted vial last?+
It depends entirely on the compound — the storage window is listed on every entry in the database. As a rough rule most reconstituted peptides hold up for a few weeks refrigerated and degrade fast at room temperature or in light. If the calculator says your vial will take three months to finish, mix less of it or use a smaller vial.
Why does the calculator warn me about small draws?+
Below about two graduation marks the measurement error swamps the dose. A 1 mL U-100 barrel is usually printed in 2-unit steps, so a 3-unit draw can easily be 33% out. Adding more water spreads the same dose across more units and makes it measurable.
48 compounds
Every peptide in the database, with its own numbers
Dosing ranges, half-lives, reconstitution volumes, storage windows, side effects and an honest read on how much human evidence there actually is.
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