Our peptides are supplied lyophilized — a technical term for freeze-dried. This is the industry standard for peptides in vials.
Peptides are supplied in this form (instead of pre-reconstituted, i.e., dissolved in bacteriostatic water) because they are much more stable in dry form. Once a peptide is reconstituted, its shelf life is 30 to 45 days in the refrigerator.
In lyophilized form, peptides can be stored for up to 2 years in the refrigerator, or up to 3 years in the freezer. Do not store peptides at room temperature for more than a week, and never expose them to heat or direct sunlight.
Reconstitution is a simple process, and we will guide you through it step-by-step in this guide. We will also show you how to calculate the injection volume based on the amount of bacteriostatic water you have used.
Recommended: Read this guide a few times before you start. Understanding each step thoroughly beforehand will make the process much smoother. Questions or uncertainties? Please contact us via our contact page.
Straight to the reconstitution and dosage calculator? Go directly to the calculator.
What you need
- Your peptide vial (lyophilized)
- Alcohol wipes
- Bacteriostatic sterile water
- 3 ml syringes (Luer Lock tip)
- 25G or 27G needles (Luer Lock). Other sizes may also be suitable.
- Sharps container (optional)
Step-by-step instructions
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Remove the caps
Remove the caps from both your peptide vial and your bacteriostatic water vial.
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Disinfect the rubber stoppers
Wipe the rubber stoppers of both vials with alcohol wipes and let them dry for about 3 minutes.
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Attach the needle
Take your 3 ml syringe and the needle. Twist the plastic needle hub into the Luer Lock tip of the syringe until it is securely fastened.
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Draw up the bacteriostatic water
Pull back the plunger to draw up the desired amount of bacteriostatic water. If you draw up too much, push the excess back until you reach the correct mark on the syringe.
How much bacteriostatic water? Small peptide vials hold a maximum of 3 ml. For these, we recommend 2 ml of bacteriostatic water, although anything between 1 ml and 3 ml is acceptable.
Larger vials: For these, you can use up to 5 ml. More bacteriostatic water makes microdosing easier, but insulin needles typically have a maximum capacity of 1 ml per injection. This means a large amount of bacteriostatic water could result in multiple injections to reach your target dose. Unless you are microdosing, 2 ml per vial is a good rule of thumb.
Later in this article, we explain the simple calculation to precisely determine how much to draw up on your insulin needle.
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Insert the needle into the peptide vial
With the bacteriostatic water in your syringe, insert the needle into the peptide vial at a slight angle to prevent pressure buildup.
Use a thin needle: Stick to 25G or higher to prevent damage to the rubber stopper. A higher gauge number means a thinner needle.
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Let the water run gently
Allow the water to slowly run down the side of the vial. Do not forcefully inject it.
Note: Sometimes the plunger pushes itself in as soon as the needle enters the vial. Hold the plunger to control the rate at which the bacteriostatic water flows into the vial.
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Swirl to dissolve
Do not shake. Gently swirl, tilt, and roll the vial to dissolve the powder.
Patience: This typically takes 2 to 5 minutes of consistent swirling, mixing in a circular motion, and gently tilting the vial up and down. The water needs to pass through the powder multiple times to dissolve it completely. Do not shake or handle it roughly.
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Check for complete dissolution
The solution should be clear, with no visible particles. If the liquid is cloudy or clumpy, wait a minute and repeat the previous step.
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Cap, dispose of materials, and store
Cap the needle and dispose of it (preferably in a sharps container). Store the reconstituted peptide vial in the refrigerator when not in use. The solution remains viable for approximately 30 days.
Frequently Asked Questions about Peptide Reconstitution
What is peptide reconstitution?
Reconstitution is the process of mixing lyophilized (freeze-dried) peptides with a sterile liquid (typically bacteriostatic water) to make them ready for research purposes.
Why bacteriostatic water instead of plain sterile water?
Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth. Sterile water does not contain a preservative and should be used immediately after mixing. Sterile water is only an option if you use the entire vial within 24 hours.
Can you freeze reconstituted peptides?
No. Freezing can damage the peptide structure. Store reconstituted peptides in the refrigerator (2 to 8 °C) and use them within 30 days. Lyophilized peptides can be stored long-term in the refrigerator or freezer, but avoid repeated thawing and refreezing.
Can you use sodium chloride (saline) instead of bacteriostatic water?
For most peptides, yes. Saline as bacteriostatic water is regularly used without issues, and some commercial products are even supplied this way. The main disadvantage of plain (non-bacteriostatic) saline is the lack of a preservative, which results in a much shorter shelf life once the vial is opened.
There is one important exception: Retatrutide should only be mixed with plain bacteriostatic water, never with sodium chloride (saline). The salt causes Retatrutide to precipitate (clump and fall out of solution), rendering the vial unusable. This is specific to Retatrutide due to its structure and does not occur with most other peptides, including Tirzepatide.
A few peptides work in the opposite way. GHRP-2 and Hexarelin are sometimes reconstituted with plain saline instead of bacteriostatic water, as a small number of users find that the benzyl alcohol in bacteriostatic water can sting or affect tolerance. This is a mild preference, not a hard rule — standard bacteriostatic water also works perfectly fine here.
In short: plain bacteriostatic water (0.9% benzyl alcohol, no sodium chloride) is the safe standard choice for everything and the mandatory choice for Retatrutide. If you only have saline with bacteriostatic water, it's fine for most peptides, but not suitable for Retatrutide.
What is the difference between IU and mg when dosing peptides?
IU (International Units) are used for hormones like HGH or insulin. Mg (milligram) is used for most other peptides.
What if you accidentally shook the vial?
Don't panic. Shaking can denature delicate peptides, but one accident isn't always fatal. Let the vial rest, check if the liquid is clear, and discard the vial if it appears cloudy or clumpy.
Can you pre-fill syringes for the entire week?
This is not recommended. Pre-filling increases the risk of contamination and can reduce the efficacy of the peptide.
What if your peptide does not dissolve completely?
Try gently warming the vial in your palm. Swirl again (never shake) and spend 2 to 3 minutes mixing, allowing the bacteriostatic water to move from top to bottom through the vial. If particles remain (very rare), please contact us.
How to calculate your dose
This is the basic formula. Not a fan of math? Go to the calculator at the bottom of this page.
Formula: Bacteriostatic water (ml) ÷ Total amount of peptide (mg) = ml per 1 mg
Once you know how many ml equals 1 mg, you can multiply or divide that number to calculate any desired dose.
Example 1: 5 mg vial, reconstituted with 2 ml bacteriostatic water
Step 1. Calculate ml per 1 mg: 2 ml ÷ 5 mg = 0.4 ml per 1 mg
So, 0.4 ml on a 1 ml insulin syringe corresponds to 1 mg of peptide. From there, scale up or down to your target dose:
- Need 1 mg? Draw up 0.4 ml
- Need 2 mg? 0.4 × 2 = 0.8 ml
- Need 0.5 mg? 0.4 ÷ 2 = 0.2 ml
Example 2: 10 mg vial, reconstituted with 2.5 ml bacteriostatic water
Step 1. Calculate ml per 1 mg: 2.5 ml ÷ 10 mg = 0.25 ml per 1 mg
Step 2. Scale to your target dose: for 2.5 mg: 0.25 × 2.5 = 0.625 ml
That is the amount you draw up on your insulin needle for 2.5 mg.
Your insulin needle has markings that allow you to measure in small increments. We recommend a 1 ml insulin needle, as it holds larger volumes than the 0.3 ml or 0.5 ml variants. Smaller syringes may require multiple injections per dose.
No math needed: use the calculator below. It does all the calculations for you.
Questions? Please contact us via our contact page.
Reconstitution and Injection Calculator
How to use the calculator: select your syringe type, enter the volume of your peptide and the amount of bacteriostatic water added, then enter your target dose. The calculator will immediately tell you exactly how much to draw up on your syringe.
Open the reconstitution and dosage calculator
These products are for research purposes only. Not for human consumption.
