What is reconstitution?

Reconstitution is the technical step that converts a lyophilized (dry) peptide into a usable aqueous solution. The vial contains a specific mass of peptide (e.g. 5 mg BPC-157). A defined volume of sterile diluent (bacteriostatic water or sterile saline) is added, and the peptide dissolves into that volume, producing a solution of known concentration.

The formula that governs reconstitution is straightforward: final concentration (mg/mL) = vial mass (mg) ÷ diluent volume (mL). A 5 mg vial reconstituted with 2 mL of bacteriostatic water produces a solution at 2.5 mg/mL. An injection volume of 0.2 mL from that solution delivers 0.5 mg of peptide. The three quantities — vial mass, concentration, injection dose — are related by this arithmetic, and confusing them is the most common reconstitution error.

The practical technique matters as much as the arithmetic. Direct the diluent stream down the vial wall rather than onto the powder directly. Swirl or roll gently rather than shaking. Do not use the vial if the reconstituted solution is cloudy, discoloured, or contains particulate. Label the reconstituted vial with the date, peptide identity, concentration, and beyond-use date.