How to reconstitute peptides
“Reconstitution” just means turning a freeze-dried peptide vial back into a liquid you can draw into a syringe. The method below is the same regardless of which peptide is in the vial — what differs molecule to molecule is the exact volume of diluent to add, and that's a number this page hands off rather than guesses at.
The “how,” not the “how much”
This page covers the mechanical method: what to wipe, how to add the diluent, how to mix it, and what to check before drawing a dose. It does not state a volume, a concentration, or a dose for any specific molecule — that arithmetic depends on your own vial's labeled strength and the amount your prescriber told you to take, and our reconstitution calculator works that out for 16 molecules once you have both numbers.
The method, step by step
Let everything reach room temperature, and clean the stoppers
Take the lyophilized (freeze-dried) powder vial and the diluent vial out of the refrigerator if either is chilled, and let them sit until they're at room temperature. Wipe both rubber stoppers with a fresh alcohol swab and let them air-dry before a needle touches either one — this is the same aseptic-entry standard bacteriostatic water's own labeling calls for on every withdrawal, not just the first.
Draw the diluent volume your prescriber or calculator specified
This is the one step this page will not do the arithmetic for. The volume of diluent you add sets the concentration of the finished solution, and the right volume depends on your specific vial's labeled mass and the dose your prescriber told you to take — two numbers only you have. Our reconstitution calculator exists specifically to turn those two numbers into a volume and a syringe reading, for 16 molecules, so this step should end with a specific number in mL rather than a guess.
Add the diluent slowly, down the inside wall of the vial
Insert the needle through the stopper and let the liquid run gently down the glass wall rather than aiming it directly at the powder. A forceful stream against dry lyophilized powder can cause foaming and, more importantly, unnecessary agitation of a molecule that is more fragile in solution than as a dry solid.
Swirl gently until clear — never shake
Roll or swirl the vial gently between your hands until the powder is fully dissolved. This matches the actual reconstitution instruction on a real FDA-approved peptide product's label — EGRIFTA SV's (tesamorelin's) prescribing information tells a patient to “mix by rolling the vial gently in your hands for 30 seconds” and explicitly “do not shake.” Vigorous shaking introduces mechanical stress and air that can denature a peptide instead of simply dissolving it.
Inspect before you draw a dose
Look at the solution before it goes anywhere near a syringe. Bacteriostatic water's own labeling instructs inspecting a reconstituted drug for clarity and freedom from unexpected precipitation or discoloration; EGRIFTA SV's label says the same thing in patient terms — use it only if it's clear, colorless, and free of visible particles. A cloudy solution, one with visible particles, or one that has changed color from when it was first mixed is a reason to stop and start over with a fresh vial, not a reason to proceed.
Sources: Hospira Bacteriostatic Water for Injection, USP labeling (DailyMed); EGRIFTA SV (tesamorelin) full prescribing information §2.2 and Patient Instructions for Use (DailyMed); CDC Injection Safety, multi-dose vial provider guidance (cdc.gov). All fetched August 2026.
The volume math lives on the calculator, not here
“How much water do I add?” and “how many units do I draw?” both have real, specific answers — but they depend on your vial's printed mass and the exact dose your prescriber gave you, so a generic worked example on this page would either be wrong for your vial or invite treating an illustrative number as an instruction. Instead: our reconstitution calculator takes your vial size, your diluent volume, and your dose, and returns the concentration, the exact draw volume, and where that lands on a standard U-100 insulin syringe — with a visual syringe reading, not just a number. It covers 16 molecules individually (tirzepatide, semaglutide, sermorelin, tesamorelin, BPC-157, TB-500, and more), each with its own reference context.
Where to go next
- Not sure what water to use, or how long a mixed vial is actually good for? Read our bacteriostatic water guide — it covers the preservative, the neonatal warning, and why the “28-day rule” and the peptide's own shelf life are two different clocks.
- Mixed and ready to draw a dose into a syringe? Our injection technique and site-rotation guide covers what comes after mixing.
- Choose your compound on the full calculator hub.
Medical disclaimer: This content is for general educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a licensed healthcare professional before starting, stopping, or changing any treatment.
This page describes a general mixing technique. It is not a recommendation for any specific peptide, dose, or diluent volume, and it does not replace instructions from the pharmacy or clinician that dispensed your prescription. Read our full medical disclaimer.