Practical Guide

Reconstitution & Dosing Guide

Peptides ship as a freeze-dried powder. Before anything else, they have to be mixed with liquid — "reconstituted." This guide explains how that works, the tools involved, and how to read your dose. Pair it with ourdose calculator.

Educational only — not medical advice. This page explains general concepts for informational purposes. It is not a prescription, dosing recommendation, or instruction to use any compound. Many peptides are sold for research use only. Always consult a licensed healthcare provider.

What "reconstitution" means

Most peptides are shipped as a small amount of white powder in a sealed glass vial. That powder is the freeze-dried (lyophilized) peptide — stable for shipping, but not yet usable. Reconstitution simply means adding a sterile liquid to turn the powder back into a solution you can measure and draw.

The key idea: the amount of peptide in the vial never changes — you're just choosing how much water to dilute it into. More water = a more dilute solution = larger draw volume per dose. Less water = more concentrated = smaller draw. The math is what our calculator does for you.

What you need

The peptide vial (powder)
Bacteriostatic water (BAC water) — the most common diluent
Alcohol prep pads (to wipe both vial stoppers)
A larger syringe (e.g. 1–3 mL) to transfer the water
An insulin syringe (U-100 is standard) to draw doses
A clean, flat surface

Bacteriostatic water & how much to add

Bacteriostatic water is sterile water with 0.9% benzyl alcohol added. The benzyl alcohol prevents bacterial growth, which lets a reconstituted vial be used across multiple doses over several weeks. (Plain sterile water and saline are sometimes used but lack that preservative.)

How much water should I add?

There's no single "correct" amount — it's a convenience choice. A common approach is to pick a water volume that makes your target dose land on an easy-to-read number of units on the syringe. For example, 2 mL of BAC water into a 5 mg vial gives 2.5 mg/mL, so a 500 mcg dose = 20 units on a U-100 syringe. Use thecalculatorto try different water volumes and see how the units change.

Step-by-step mixing

Let both vials reach room temperature. Wipe both rubber stoppers with an alcohol pad.
Draw your chosen amount of BAC water into the transfer syringe.
Insert the needle into the peptide vial and aim the stream against the glass wall, not directly onto the powder. Let it run down slowly.
Remove the needle. Do not shake. Gently swirl or let it sit; the powder dissolves on its own in a minute or two.
The solution should be clear. If it stays cloudy or has particles, something's off — don't use it.
Store in the fridge and draw doses with an insulin syringe as needed.

Syringe types (U-100 / U-50 / U-40)

Insulin syringes are labeled by their "U" rating, which sets how units map to volume:

Syringe	Full barrel	Units → volume
U-100	1 mL = 100 units	1 unit = 0.01 mL
U-50	0.5 mL = 50 units	1 unit = 0.01 mL
U-40	1 mL = 40 units	1 unit = 0.025 mL

U-100 is by far the most common. The important thing is to know which syringe you have, because "20 units" means a different volume on a U-40 than a U-100. Our calculator lets you pick the syringe so the units it shows match your actual syringe.

Reading your dose in units

The chain is: vial mg ÷ water mL = concentration (mg/mL), thendose ÷ concentration = volume, then volume converts to units on your syringe.

Rather than doing this by hand every time, plug your numbers into thePepEvolution dose calculator — it shows the exact units to draw, the concentration, and how many doses your vial holds, and warns you if a dose exceeds the syringe's capacity.

Open the dose calculator →

Storage & shelf life

Powder (lyophilized): store cool and dark; freezer is fine for long-term. Very stable.
Reconstituted (mixed): refrigerate (≈ 36–46°F / 2–8°C). With BAC water, many peptides remain stable for several weeks.
Keep out of direct light and heat. Don't leave vials at room temperature for extended periods.
Never freeze a reconstituted vial unless the specific peptide is known to tolerate it.

Common mistakes to avoid

Shaking the vial. Peptides are fragile — swirl gently, don't shake.
Spraying water directly onto the powder. Aim for the glass wall.
Mismatching syringe type. Units differ between U-100 and U-40.
Guessing the dose. Run the numbers; small errors compound at low doses.
Using cloudy/contaminated solution. When in doubt, throw it out.
Skipping the alcohol wipe on the stopper before each draw.

One more time: this is general educational information, not medical advice and not a recommendation to use any compound. Many peptides are sold for research use only. Talk to a licensed healthcare provider before doing anything with a peptide.