Reconstitution means adding bacteriostatic water to activate your freeze-dried peptide powder. The amount of water determines how concentrated your solution is — more water means weaker, less means stronger. The process: clean vial tops, draw water, add it gently at an angle (never directly on powder), let it dissolve naturally, and refrigerate immediately.
Reconstitution is a sterile procedure and should be treated as one. Your tools — needles, syringes, vials — should never contact non-sterile surfaces. Work on a clean, wiped surface and keep needles capped until the moment of use. The most common contamination vector is not the water — it's transferring bacteria from hands, surfaces, or a re-capped needle that touched something it shouldn't have.
Bacteriostatic water is specifically formulated for multi-use vials. The 0.9% benzyl alcohol content inhibits bacterial growth, which is why reconstituted peptides stay stable in the fridge for 3-4 weeks instead of spoiling quickly. Sterile water (without benzyl alcohol) is an alternative for people sensitive to benzyl alcohol, but your reconstituted peptide should then be used within 24-48 hours rather than weeks.
The concentration you choose determines how many syringe units you draw per injection. The most common approach is adding 1-2 mL of BAC water to a standard 5 mg vial, resulting in a 5,000 mcg/mL or 2,500 mcg/mL solution. Lower concentration (more water) makes dosing easier to measure precisely. Higher concentration (less water) means smaller injection volume per dose. Peptide Upside's reconstitution calculator handles this math — input your vial size and target dose to get the exact water amount.
Why not shake the vial? Peptide molecules are fragile three-dimensional structures. Vigorous shaking introduces air bubbles and can mechanically denature (unfold) the peptide chains, reducing potency. Always swirl gently and let gravity do the work. If the powder does not dissolve within a few minutes, roll the vial slowly between your palms. A properly reconstituted peptide solution should be clear and colorless — slight cloudiness can indicate degradation.
Label your vials immediately after reconstituting. Write the compound name, date mixed, and concentration on a small piece of masking tape. Managing even two active vials without labels leads to errors. Store reconstituted vials toward the back of the refrigerator, away from the door where temperature fluctuates with every opening. A consistent 36-40°F is the target — the coldest stable zone in most home refrigerators.
Bacteriostatic water (BAC water) is sterile water with 0.9% benzyl alcohol added to prevent bacterial growth. It's the standard diluent for reconstituting peptides and keeps your mixed vial stable for 3-4 weeks.
The amount depends on your desired concentration. Peptide Upside's reconstitution calculator tells you exactly how much BAC water to add based on your vial size and target dose.
No. You should use bacteriostatic water or sterile water for injection. Regular tap or bottled water is not sterile and could contaminate your peptide.
Written by Peppa at Peptide Upside — the peptide lifestyle guide for real people. Research compounds, calculate doses, and track your journey.