Reconstitution 101 — turning powder into a research solution
Step-by-step: choosing a solvent, calculating concentration, using an insulin syringe, and avoiding the common mistakes that ruin a vial.
What you need
A sealed lyophilized peptide vial with a visible pellet or fluff.
Bacteriostatic water (BAC — 0.9% benzyl alcohol) for anything you plan to use across multiple days. Sterile water only for single-use scenarios.
A 1 mL luer-slip syringe with an 18–22 g draw needle for transferring solvent.
A U-100 insulin syringe (0.3 mL or 0.5 mL) for measured research doses.
70% isopropyl alcohol pads for every rubber-stopper puncture.
Step-by-step
1. Let the lyophilized vial equilibrate to room temperature. Cold vials pull condensation.
2. Swab both stoppers (solvent + peptide) with a fresh alcohol pad.
3. Draw the calculated volume of BAC into the transfer syringe.
4. Insert the needle at a 45° angle and let the solvent trickle down the inside wall of the peptide vial. Do not blast it onto the pellet.
5. Remove the needle. Do NOT shake. Swirl gently or let it dissolve passively over 2–5 minutes.
6. Once fully clear, label the vial with the compound, concentration, and date reconstituted.
The concentration math (memorize this)
Concentration (mg/mL) = mg of peptide in the vial ÷ mL of solvent you added.
Example: 5 mg vial + 2 mL BAC = 2.5 mg/mL.
On a U-100 insulin syringe, 100 units = 1 mL. So 10 units = 0.1 mL.
At 2.5 mg/mL, 10 units delivers 0.1 mL × 2.5 mg/mL = 0.25 mg = 250 mcg.
Common mistakes
Shaking the vial — mechanical stress can denature the peptide.
Injecting solvent directly onto the pellet at high pressure.
Skipping the alcohol swab on repeated draws (contamination risk grows with each puncture).
Forgetting to label — a mystery vial in the fridge is a wasted vial.