How to Reconstitute Peptides

Reconstitution is the process of mixing lyophilized (freeze-dried) peptide powder with bacteriostatic water to create an injectable solution. Peptides are shipped as powder because they're more stable in this form. Once reconstituted, the solution must be refrigerated, and how long it stays good depends on the compound.

Lyophilized peptide vial, bacteriostatic water (BAC water — sterile water with 0.9% benzyl alcohol preservative), insulin syringe for mixing, alcohol swabs, and a clean workspace. Never use plain sterile water — it lacks the preservative needed for multi-use vials.

Wash your hands thoroughly. Wipe the tops of both the peptide vial and the BAC water vial with alcohol swabs. Let the alcohol dry completely before proceeding. Work on a clean, flat surface.

Using a fresh insulin syringe, draw the desired amount of BAC water. Common amounts are 1mL or 2mL depending on the peptide. Our calculator will tell you the optimal amount for your specific peptide and desired concentration.

Insert the needle through the rubber stopper of the peptide vial. Angle the syringe so water runs down the inside wall of the vial — do NOT squirt water directly onto the powder cake. Release the water slowly. The peptide is delicate and vigorous mixing can damage it.

Do NOT shake the vial. Instead, gently swirl it in small circles or simply let it sit for a few minutes. The powder should dissolve into a clear solution within 5-10 minutes. If particles remain after 10 minutes, continue gentle swirling. If the solution is cloudy, it may indicate degradation.

Once reconstituted, immediately refrigerate the vial at 2-8°C (36-46°F). Keep it away from light. Label the vial with the reconstitution date. How long it stays stable varies by compound, from hours to months, so check the storage guidance on that peptide's page before relying on a date.

Want this beside your supplies? Print the peptide reconstitution guide (free PDF). One page with the mixing math, a units-to-draw table, syringe sizes, and the safety checklist.