How do you reconstitute a peptide vial?

Let both vials reach room temperature, wipe both stoppers with alcohol, draw the intended volume of bacteriostatic water, insert the needle at an angle so the water runs down the inside wall of the vial rather than jetting onto the powder, let it dissolve on its own, and swirl gently if needed. Do not shake.

Why should you not shake a reconstituted peptide?

Shaking creates foam and shear forces at the air-liquid interface, which can denature peptides. Gentle swirling and time achieve the same dissolution without the mechanical stress.

How long does a reconstituted peptide last?

Bacteriostatic water's benzyl alcohol preservative is commonly labelled for 28 days after first puncture, and reconstituted product is generally refrigerated. Follow the storage instructions on the specific product you have rather than a general rule.

Guide

How to reconstitute a peptide, step by step

By Melvin Morina · Updated 2026-07-27

The short version: bring both vials to room temperature, swab both stoppers with alcohol, draw your bacteriostatic water, and inject it against the inside wall of the vial so it runs down rather than jetting onto the powder. Let it dissolve by itself, swirl gently if it needs help, never shake, then refrigerate. The volume of water you choose changes the units you draw, not the dose you receive.

The sequence

Room temperature first. Cold glass and cold liquid dissolve slower and encourage condensation.
Swab both stoppers with an alcohol wipe and let them dry. Wet alcohol dragged through the septum defeats the point.
Draw your water. Decide the volume before you start — it determines where every future dose lands on the syringe. Work it out with the calculator.
Angle the needle so the stream hits the glass wall and runs down. Firing water directly onto lyophilised powder is the most common avoidable damage.
Wait. Most peptides dissolve on their own within a minute or two. Gentle swirling is fine; shaking is not.
Inspect. The solution should be clear. Cloudiness, floating particles or persistent undissolved material after time means something is wrong — do not use it.
Refrigerate and label the vial with the date and concentration.

What ruins a vial

Shaking. Foaming at the air-liquid interface denatures peptides. Swirl, or just wait.
Blasting the powder. Aim at the wall, not the cake.
Guessing the water volume, then guessing again next time. Different volumes on different vials is how dosing errors happen. Pick a volume and keep it consistent.
Freezing reconstituted solution. Freeze-thaw cycles are hard on peptides; the powder is the stable form, not the liquid.
Leaving it in light and heat. Back of the fridge, not the door.

Storage

Bacteriostatic water is preserved with benzyl alcohol, and product labelling commonly specifies discarding it 28 days after the first puncture. Sterile water has no preservative at all and is single-use. Reconstituted vials are normally refrigerated. Always follow the label on the specific product in your hand — these are general conventions, not a substitute for it.

The dose math

Concentration is vial milligrams divided by water millilitres. Volume for a dose is dose milligrams divided by that concentration. Units are volume times 100 on a U-100 syringe. More water never means less drug: it means more units for the same milligrams. The calculator does all three steps →

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Bo remembers your vial and water volume and puts the unit number on every dose reminder, so the calculation happens once instead of every week.

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Educational information only. Bo is a tracking app, not a medical device, and nothing here is medical advice, a dosing recommendation, or a substitute for your prescriber. Half-lives are population averages from the sources cited on each row; individual clearance varies with body weight, kidney and liver function, and other medication.