Peptide Calculator

Reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder with a sterile diluent—usually bacteriostatic water—to create an injectable solution. The peptide arrives as a delicate powder cake in a sealed vial. By slowly adding a precise amount of bacteriostatic water, you turn it into a measurable liquid that can be drawn into an insulin syringe for accurate dosing.

There is no single "correct" amount; the volume you add simply changes the concentration. Adding more water means a lower concentration (larger injection volumes per dose), while less water means a higher concentration (smaller injection volumes). Most researchers use 1–2 mL for smaller vials (2–5 mg) and 2–3 mL for larger vials (10–20 mg) to keep injection volumes practical. Our reconstitution calculator above lets you experiment with different volumes instantly.

A standard U-100 insulin syringe has 100 unit markings that correspond to 1 mL total volume. Each unit equals 0.01 mL. So if the calculator says to draw 0.25 mL per dose, you would draw to the 25-unit mark on your syringe. Common syringes come in 0.3 mL (30 units), 0.5 mL (50 units), and 1 mL (100 units) sizes. Choose the smallest syringe that accommodates your dose volume for the greatest accuracy.

Sterile water for injection is safe for single-use reconstitution but contains no preservative. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows the reconstituted peptide to be stored and drawn from multiple times over days or weeks. If you use sterile water, the vial should ideally be used within 24 hours and kept refrigerated. For multi-dose vials, bacteriostatic water is strongly recommended.

When mixed with bacteriostatic water and stored refrigerated (36–46 °F / 2–8 °C), most reconstituted peptides remain stable for approximately 28–30 days. Some peptides may degrade faster depending on their chemical structure. Never freeze reconstituted peptide, keep it away from light, and discard any solution that appears cloudy, discolored, or has visible particles.

No. The total amount of peptide in the vial stays the same regardless of how much water you add. Adding more water dilutes the concentration, so you need a larger volume per injection to get the same microgram dose. Adding less water concentrates it, so you need a smaller volume. The calculator handles this math for you—just enter your vial size, water volume, and desired dose to see exactly how much to draw.

Insulin syringes (U-100) are the standard for subcutaneous peptide injections. They come in three sizes: 0.3 mL (30 units), 0.5 mL (50 units), and 1 mL (100 units). For most peptide doses, a 0.5 mL or 1 mL syringe with a 29–31 gauge, ½-inch needle works well. Choose the smallest syringe that fits your dose volume for the best accuracy and easiest reading.

Store reconstituted peptides in the refrigerator at 36–46 °F (2–8 °C). Keep the vial upright, protect it from light, and never freeze it. Unreconstituted (lyophilized) peptides can often be stored at room temperature or frozen for long-term storage, depending on the manufacturer's guidance. Always check the specific peptide's storage recommendations.

No. This calculator is an educational tool designed for research purposes only. It performs unit-conversion mathematics to help you understand reconstitution concentrations and dosing volumes. It does not provide medical advice, diagnoses, or treatment recommendations. Always consult a qualified healthcare professional before using any peptide or research compound.

If the peptide powder doesn't dissolve after adding bacteriostatic water, gently swirl the vial—never shake vigorously, as this can damage delicate peptide bonds. Allow it to sit refrigerated for a few minutes and try swirling again. Most research-grade peptides dissolve within 1–3 minutes of gentle swirling. If the powder still won't dissolve after several attempts, the peptide may be degraded or of low quality.