Peptide Calculator: Reconstitution, Dosage & Syringe Conversion

The standard ratio for a 5mg peptide vial is 2mL of bacteriostatic water. This creates a concentration of 2.5mg/mL, where every 0.1mL (10 units on a U-100 insulin syringe) delivers exactly 250mcg. You can adjust this ratio — use our peptide calculator above to recalculate for any water volume.

The number of units for a 250mcg dose depends on your reconstitution ratio. For a 5mg vial mixed with 2mL of BAC water, 250mcg equals exactly 10 units (0.1mL) on a U-100 syringe. Use the peptide dosage calculator to find the precise unit count for your specific vial and water volume.

A U-100 syringe contains 100 units per 1mL. A U-40 syringe contains only 40 units per 1mL. Nearly all peptide research sessions use U-100 syringes. Drawing the same number of markings on a U-40 syringe delivers 2.5 times more volume than a U-100 — a critical distinction that can lead to significant dosing errors if unrecognized.

Always roll, never shake. Shaking a peptide vial creates mechanical stress that can disrupt the amino acid chains in the compound. Instead, gently roll the vial between your palms in a smooth, circular motion until the lyophilized powder is fully dissolved in the bacteriostatic water.

Most peptide solutions reconstituted with bacteriostatic water remain stable for 28–30 days when stored at 2–8°C (standard refrigerator temperature). After this window, degradation accelerates. For extended storage, some researchers prefer to keep unreconstituted lyophilized peptides frozen and reconstitute only what is needed per research session.

For a 10mg vial, adding 2mL of bacteriostatic water creates a 5mg/mL concentration, where a 250mcg dose equals 5 units on a U-100 syringe. Adding 5mL instead creates a 2mg/mL concentration, where the same dose equals 12.5 units — easier to measure precisely. Use the peptide reconstitution calculator above to find the optimal ratio for your dose range.

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a sterile liquid carrier — typically bacteriostatic water — to create an injectable solution ready for research use. The ratio of peptide to water determines the concentration of the final solution, which dictates how many syringe units correspond to any given dose.

To convert micrograms (mcg) to milligrams (mg), divide by 1,000. For example, 500mcg = 0.5mg. To convert mg to mcg, multiply by 1,000. So a 5mg vial contains 5,000mcg of peptide. This conversion is the foundation of all peptide dosage calculations.

Sterile water can technically dissolve peptides, but it lacks the 0.9% benzyl alcohol preservative found in bacteriostatic water. Without this preservative, microbial growth is possible and the reconstituted solution's shelf life is dramatically reduced — typically to 24 hours. For any research session extending beyond a single day, bacteriostatic water is strongly preferred.

The volume of bacteriostatic water you add determines your peptide solution's concentration — and therefore how many syringe units correspond to your target dose. Using inconsistent water volumes across sessions creates inconsistent dosing, even with the same vial. Always note the exact water volume used and recalculate using the peptide calculator if you change your reconstitution ratio.