Interactive Tool
Reconstitution Calculator
Calculate the concentration, syringe units, and doses per vial when reconstituting any peptide with bacteriostatic water.
Research Purposes Only: All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.
Quick Fill
✓ Auto-filled vial size, water amount, and typical dose for Retatrutide
Vial Information
Dose Settings
Enter the research dose in micrograms
Draw This Amount
= 0.1 mL for a 250 mcg dose
Concentration
2,500 mcg/mL
Per Syringe Unit
25.00 mcg
Doses per Vial
20
at 250 mcg each
Total in Vial
5,000 mcg
5 mg total
Syringe Fill Level
Summary: Add 2 mL of bacteriostatic water to a 5 mg vial. Each 100-unit syringe tick mark equals 25.00 mcg. For a 250 mcg dose, draw to 10 units. This vial provides approximately 20 doses.
How Peptide Reconstitution Works
Reconstitution is the process of adding bacteriostatic water to a lyophilized (freeze-dried) peptide powder to create an injectable solution. The amount of water you add determines the concentration of the solution, which in turn determines how many syringe units correspond to a given dose.
The basic formula is: Concentration (mcg/mL) = Vial Size (mg) × 1000 ÷ Water Added (mL). For example, adding 2 mL of water to a 5 mg vial gives a concentration of 2,500 mcg/mL. On a standard 100-unit insulin syringe (where 100 units = 1 mL), each tick mark represents 25 mcg. To draw 250 mcg, you would draw to the 10-unit mark.
Always use bacteriostatic water (not sterile water) for multi-use vials, as the 0.9% benzyl alcohol preservative prevents bacterial growth. Direct the water stream against the glass wall of the vial rather than directly onto the powder, and swirl gently to dissolve. Never shake.
Frequently Asked Questions
Enter your peptide vial size (in mg), the amount of bacteriostatic water you want to add (in mL), your desired dose (in mcg), and your syringe size. The calculator instantly shows the resulting concentration and exactly how many syringe units to draw.
Yes — the amount of water determines the concentration. More water means a more dilute solution (more units per dose, easier to measure small doses). Less water means a more concentrated solution (fewer units per dose, but harder to measure precisely). Most protocols use 1-2 mL for standard vials.
A 100-unit (1 mL) insulin syringe is most common. For very small doses, a 50-unit (0.5 mL) or 30-unit (0.3 mL) syringe offers finer graduation marks for more precise measurement. The calculator adjusts its output based on your syringe selection.