Peptide Reconstitution Calculator
Calculate exact BAC water volume, concentration per ml, U-100 syringe units, and view an interactive visual barrel fill level.
Calculators by compound
The same arithmetic, prefilled with a common vial size and mixing volume, alongside what the published evidence says about that compound. No page prefills a dose.
- Semaglutide
- Tirzepatide
- Retatrutide
- Cagrilintide
- Orforglipron
- Survodutide
- Pentadeca Arginate
- BPC-157
- TB-500
- Ipamorelin
- CJC-1295 without DAC
- PT-141
- Tesamorelin
- Semax
- Epithalon
- NAD+
- Glutathione
- GHK-Cu
- Sermorelin
- DSIP (Delta Sleep-Inducing Peptide)
- Selank
- MOTS-c
- SS-31 (Elamipretide)
- Kisspeptin
- Thymosin Alpha-1
- KPV
- MK-677 (Ibutamoren)
- IGF-1 LR3
- All compounds
Understanding Peptide Reconstitution Arithmetic
Written out so you can check it by hand. The app runs this exact function, not a second implementation that drifts.
Reconstitution math determines how concentrated a peptide solution becomes when mixed with diluent. The fundamental relationship relies on three core variables: total peptide mass in the vial (e.g., 5 mg), volume of Bacteriostatic (BAC) water added (e.g., 2 ml), and your intended target dose (e.g., 250 mcg).
1. Solution Concentration: Concentration (mg/ml) = Vial Mass (mg) ÷ BAC Water Volume (ml). Adding 2 ml of BAC water to a 5 mg vial yields a concentration of 2.5 mg/ml (or 2,500 mcg/ml).
2. Draw Volume: Draw Volume (ml) = Target Dose (mg) ÷ Concentration (mg/ml). For a 250 mcg (0.25 mg) dose from a 2.5 mg/ml solution, the draw volume is 0.25 ÷ 2.5 = 0.10 ml.
3. Syringe Units (U-100): Standard insulin syringes use a U-100 scale where 1.0 ml = 100 units. Multiplying 0.10 ml × 100 yields exactly 10 units on the barrel.
- What is peptide reconstitution?
- Reconstitution is the process of dissolving lyophilized (freeze-dried) peptide powder in a diluent, typically Bacteriostatic Water (0.9% benzyl alcohol), to produce a sterile liquid solution suitable for measurement and administration.
- How do I calculate U-100 syringe units for my target dose?
- For a standard U-100 insulin syringe, 1.0 ml equals 100 units (10 units = 0.1 ml). To calculate your draw in units: divide your desired target dose (in mg) by the vial concentration (in mg/ml) to find draw volume in ml, then multiply by 100.
- Why use Bacteriostatic Water instead of plain Sterile Water?
- Bacteriostatic Water contains 0.9% benzyl alcohol, a preservative that prevents microbial growth after the rubber vial stopper is punctured. Plain sterile water lacks preservatives and is intended for single-use immediate administration only. Source: FDA labeling for Bacteriostatic Water for Injection, USP.
- Which syringe barrel size should I select?
- Select a barrel size slightly larger than your target draw. A 0.3 ml barrel (30 units) provides fine half-unit gradations for small doses. A 0.5 ml barrel (50 units) handles medium doses, while a 1.0 ml barrel (100 units) is used for larger volumes.
- What are the most common reconstitution math mistakes?
- Three recur. Slipping a factor of 1,000 between mg and mcg (a 250 mcg dose is 0.25 mg, not 2.5). Treating syringe units as a mass unit: units measure volume, so the same dose is a different number of units at a different concentration. And reading the vial label as a concentration: 5 mg on the label is total content, and means nothing per ml until you divide by the diluent volume you added.
- How long does a reconstituted peptide vial remain usable?
- A punctured multi-dose vial should be discarded within 28 days (the window USP <797> and CDC injection-safety guidance set unless the manufacturer specifies otherwise). Store refrigerated at 2–8°C (36–46°F); chemical stability beyond that varies by compound and is not guaranteed.
The number is right. Now keep the record.
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