6 min read · Also in the Dose Track app under Learn · Updated
Short answer: Reconstituting means adding liquid to the powder in a vial so you can draw doses. Use bacteriostatic water for a vial you will use more than once, run it slowly down the inside wall of the vial, swirl gently instead of shaking, and label the vial with the date and strength. Work out the math before your first draw.
Steps
Wash and set upWash your hands. Lay out the peptide vial, bacteriostatic water, an insulin syringe, alcohol swabs and a marker on a clean surface.
Swab both stoppersWipe the rubber top of the peptide vial and the water vial with separate alcohol swabs. Let them dry.
Draw the waterDecide how much water you will add (see the math below). Draw that amount from the water vial.
Aim at the glassPush the needle through the peptide vial stopper, tilt the vial, and point the needle at the inside wall, not at the powder.
Add it slowlyPress the plunger slowly so the water runs down the glass onto the powder.
Swirl, do not shakeTake the needle out and gently roll or swirl the vial until the powder dissolves. Shaking makes foam and can make peptides clump.
Check and labelThe liquid should be clear, with no particles. Write the name, the date you mixed it and the strength (for example 2.5 mg/mL) on the vial.
What reconstitution is
Many peptides ship as a freeze-dried (lyophilized) powder, which keeps them stable. Adding liquid turns the powder into a solution with a known strength you can measure doses from.
Which water to use
Bacteriostatic water is sterile water with 0.9% benzyl alcohol, a preservative that slows bacterial growth. It comes in multiple-dose vials, so it suits a vial you draw from many times. Its label says it is not for use in newborns.
Sterile water for injection has no preservative and is meant for one use. Fine if you use the whole vial at once.
Tap or bottled water: never. It is not sterile.
Some peptides need a different liquid per their maker. Follow the product's own directions if it has them.
The concentration math
Strength (mcg per mL) = peptide in the vial (mcg) ÷ water added (mL). Then dose volume (mL) = your dose (mcg) ÷ strength.
Worked example: 5 mg vial, 2 mL water
5 mg = 5,000 mcg.
5,000 mcg ÷ 2 mL = 2,500 mcg per mL.
For a 250 mcg amount: 250 ÷ 2,500 = 0.1 mL.
On a U-100 insulin syringe, 0.1 mL = 10 units.
Research info, not a recommendation. Amounts, schedules and timing in this section come from studies (often in animals) and from how people commonly use these compounds. Most are not FDA-approved doses. Your dose is a decision for you and your prescriber.
Same 5 mg vial, different water amounts (250 mcg is an example amount, not a recommendation)
Water added
Strength
250 mcg on a U-100 syringe
1 mL
5,000 mcg/mL
5 units
2 mL
2,500 mcg/mL
10 units
5 mL
1,000 mcg/mL
25 units
Pick a water amount that puts your dose on an easy-to-read mark. The reconstitution calculator does this math for any vial.
After mixing: storage and how long it lasts
Keep it in the fridge at 2 to 8 °C (36 to 46 °F), toward the back, not in the door.
Keep it out of light (in its box or wrapped).
Do not freeze a vial you are drawing from.
Date it. In clinics, a multi-dose vial is thrown out 28 days after it is first punctured unless the maker gives a different date. That rule is about germs, not strength. Lab suppliers such as Thermo Fisher advise using dissolved peptides within about a week, and most research peptides have no published data on how long they stay potent once mixed. Treat 28 days as an upper limit, not a promise.
When to throw it out
Cloudy, milky or has particles.
An odd color when it should be clear.
Past your 28-day date or the maker's date.
Left warm for a long time, or frozen.
When in doubt, throw it out. A vial costs less than an infection.
Key points
Use bacteriostatic water for a vial you will draw from more than once.
Run the water down the glass and swirl; do not shake.
Strength = mcg in the vial ÷ mL of water; dose volume = dose ÷ strength.
Refrigerate, protect from light, date the vial and discard by 28 days or sooner.
Can I use sterile water instead of bacteriostatic water?+
Sterile water has no preservative and is meant for one use. For a vial you draw from over days or weeks, bacteriostatic water is the usual choice.
How long does a mixed peptide vial last?+
Clinics throw out multi-dose vials 28 days after the first puncture unless the maker says otherwise, to limit germs. Lab suppliers advise using dissolved peptides within about a week, and most research peptides have no published stability data, so treat 28 days as an upper limit.
How many units is 0.1 mL?+
On a U-100 insulin syringe, 0.1 mL is 10 units. On a U-40 syringe it is 4 units.