Most peptides arrive as lyophilized (freeze-dried) powder. Reconstitution means adding a diluent (commonly bacteriostatic water) to dissolve the powder so it can be drawn into a syringe.

Bacteriostatic water (BaW) is sterile water containing 0.9% benzyl alcohol. The preservative inhibits bacterial growth in multi-dose vials, allowing repeated withdrawals for up to 28 days once opened (if stored correctly). It is not the same as sterile water for injection (SWFI).

It depends on the concentration you want. Example: 5 mg peptide + 2 mL BaW → 2.5 mg/mL (2500 µg/mL). Use the calculator above to target a per-mL strength that makes dosing simple.

Volume (mL) = Desired dose (mg) ÷ Vial strength (mg/mL). Example: If vial strength is 2.5 mg/mL and you want 0.5 mg: 0.5 ÷ 2.5 = 0.20 mL.

• Refrigerate (2–8 °C / 36–46 °F) unless your product instructions state otherwise.
• Label the vial with date and concentration (e.g., “5 mg in 2 mL = 2.5 mg/mL”).
• Minimize temperature cycling; keep out of light.

General practice: use within 28 days when mixed with BaW and refrigerated. Actual stability varies by peptide and manufacturer—follow your product’s guidance.

You can, but SWFI lacks a preservative and is typically intended for single-use. For multi-dose vials, BaW is generally preferred (follow your clinician’s instructions).

• Alcohol swab stoppers and skin; let dry.
• Use new sterile needles/syringes each time.
• Do not leave needles in the vial. Cap promptly; refrigerate.