Tools

Reconstitution Guide

How to turn a lyophilized peptide vial into a measured liquid — the supplies, the concepts, and the steps. For the exact numbers, pair this with the Reconstitution Calculator.

What reconstitution is

Many research peptides ship as a lyophilized (freeze-dried) powder for stability. Before the contents can be measured out, the powder is dissolved back into a liquid by adding a measured volume of sterile diluent — usually bacteriostatic water. That process is called reconstitution. Once dissolved, the amount of peptide in each fraction of a milliliter is fixed by two numbers you control: how much peptide is in the vial, and how much water you add.

This guide explains the concepts and the general procedure. For the exact figures — concentration and how many syringe units a given dose works out to — use the Reconstitution Calculator.

What you need

The vial — the lyophilized powder, with its labeled amount in milligrams (mg).
Bacteriostatic water — sterile water containing ~0.9% benzyl alcohol, which lets a multi-use vial be re-entered over days without bacterial growth.
A U-100 insulin syringe — graduated in "units" (1 unit = 0.01 mL), which is what you'll draw the reconstituted liquid with.
Alcohol swabs — to wipe both vial stoppers before every needle entry.
(Optional) a separate larger syringe/needle — some people use one syringe to add the water and the insulin syringe only for drawing doses.

Key concepts

Bacteriostatic vs. sterile water. Plain sterile water and sterile saline have no preservative, so they suit single-use only. Bacteriostatic water's benzyl alcohol is what makes a vial that's entered repeatedly over time the common choice for reconstitution.

What a "unit" is. On a U-100 insulin syringe, the scale is in units, not milligrams. One unit is always 0.01 mL of liquid, whatever the syringe's total size. The syringe measures volume — it has no idea how concentrated your liquid is.

Concentration is the link. Concentration (mg per mL) = peptide in the vial ÷ water added. More water → lower concentration → more units per dose (and finer adjustment); less water → higher concentration → fewer units per dose. The peptide amount per dose doesn't change — only how many units of liquid carry it. The calculator does this arithmetic for you.

Step by step

Let the vial and water reach room temperature, and wash your hands. Wipe both rubber stoppers with a fresh alcohol swab.
Draw your planned volume of bacteriostatic water into the syringe.
Insert the needle into the peptide vial and add the water slowly, aiming the stream down the inside wall of the vial — not directly onto the powder.
Remove the needle and swirl gently until fully dissolved. Do not shake — agitation can damage fragile peptides and create foam.
Let it sit until the solution is completely clear with no visible particles before drawing any dose.
Label the vial with the contents and the date, and store it (see below).

Storage & handling

Keep reconstituted vials refrigerated and protected from light; don't freeze unless a source specifically indicates it.
Reconstituted peptides have a limited shelf life — generally a matter of weeks, far shorter than the dry powder. When in doubt, discard.
Always label with the date of reconstitution so you can track it.
Lyophilized (un-mixed) powder is far more stable and is usually stored cold and dark until use.

Sterility & safety

Swab the stopper every time before inserting a needle.
Use a new, sterile needle each time; never reuse or share needles or vials.
Discard the vial if the solution turns cloudy, changes color, or shows particles or growth.
Dispose of needles in a proper sharps container.

Common mistakes

Shaking instead of swirling — can degrade the peptide and foam the solution.
Using the wrong water (tap, non-sterile, or expecting plain sterile water to keep a multi-use vial).
Confusing units and milligrams — the syringe reads volume in units; the calculator converts your dose to units.
Squirting water directly onto the powder forcefully, rather than running it down the wall.
Assuming a different water volume gives the same units — change the water, and the units-per-dose change too.

FAQ

Does more or less water change the total amount of peptide?

No. The vial holds a fixed amount of peptide. Water only changes the concentration — i.e., how many syringe units carry a given dose. More water means more units per dose, which can make small doses easier to measure.

Why bacteriostatic water specifically?

Its benzyl alcohol preservative is what allows a vial to be re-entered over time without bacterial growth. Plain sterile water and saline have no preservative.

How long does a reconstituted vial last?

Generally weeks when refrigerated and handled cleanly — much shorter than the dry powder. Specifics vary; when uncertain, discard.

How do I know how many units to draw?

That's exactly what the calculator is for — enter the vial amount, the water you added, and your intended dose, and it returns the units to draw on a U-100 syringe.

Run your numbers · Reconstitution Calculator →

Educational information only. This guide explains the general reconstitution process. It is not medical advice, a dosing recommendation, or a protocol for human use, and it does not tell you whether, what, or how much to take. Many peptides are not approved for human use. Follow applicable laws, verify every detail independently, and consult a licensed clinician.