Guide

How to reconstitute a peptide

Everything from the box of powder to a labeled vial in the fridge. Ten minutes the first time, two minutes after that.

Units, routes, storage

Step by step

1
Gather everything first
Lyophilized peptide vial, bacteriostatic water, a mixing syringe (3 mL with an 18 to 22 gauge needle is easiest), alcohol swabs, and insulin syringes for dosing. Wash your hands. Work on a clean surface.
2
Let the vial come to room temperature
Cold glass plus warm water can cause condensation and, in rare cases, cracking. Ten minutes on the counter is enough. Swab both rubber stoppers with alcohol and let them dry.
3
Decide on the water volume before you start
Use the calculator to pick a volume that puts your dose between roughly 5 and 50 units. Write the volume on the vial with a marker. You will forget otherwise, and the concentration is meaningless without it.
4
Draw the water
Pull the chosen volume into the mixing syringe. Pull a little air in first and push it into the water vial to make drawing easier. Tap out bubbles.
5
Add it slowly down the glass
Insert the needle at an angle and let the water run down the inside wall of the vial, not straight onto the powder. Peptides are fragile chains. A hard stream can damage them and cause foaming.
6
Swirl, do not shake
Roll the vial gently between your fingers or leave it alone for a few minutes. Most peptides dissolve clear within a minute or two. Larger or lipophilic ones can take longer and may stay faintly hazy, which is usually fine. Visible particles that do not dissolve are not fine.
7
Label and refrigerate
Date, water volume, and concentration on the vial. Into the fridge at 2 to 8 C, out of light. Not the freezer once reconstituted, since freeze-thaw cycles break peptides down.
8
Draw doses with a fresh insulin syringe every time
Swab the stopper, draw slightly more than you need, push out the excess and bubbles, inject. Never reuse a needle. Rotate injection sites.

How much bacteriostatic water

The water volume sets the concentration and nothing else. Pick one that makes your usual dose easy to measure. Here are common combinations and what one syringe unit works out to.

Vial	Water	Concentration	Per unit (U-100)	250 mcg dose	1 mg dose
2 mg	1 mL	2 mg/mL	20 mcg	12.5 units	50 units
5 mg	1 mL	5 mg/mL	50 mcg	5 units	20 units
5 mg	2 mL	2.5 mg/mL	25 mcg	10 units	40 units
10 mg	2 mL	5 mg/mL	50 mcg	5 units	20 units
10 mg	3 mL	3.33 mg/mL	33 mcg	7.6 units	30.3 units
15 mg	3 mL	5 mg/mL	50 mcg	5 units	20 units
30 mg	3 mL	10 mg/mL	100 mcg	2.5 units	10 units
50 mg	2 mL	25 mg/mL	250 mcg	1 units	4 units

Anything else: use the calculator.

Bacteriostatic versus sterile water

Bacteriostatic water contains 0.9% benzyl alcohol, which keeps bacteria from growing in a vial you will puncture repeatedly over weeks. That is what you want for any multi-dose vial. Plain sterile water has no preservative and is only appropriate if you will use the whole vial within a day or so. Do not use tap water, distilled water from the store, or saline meant for contact lenses.

What if I added the wrong amount?

Nothing is ruined. The peptide is still all in there. Recalculate the concentration with the volume you actually used and adjust your draw. If you do not know how much you added, you have a problem, which is why step 3 says write it down first.

Reading an insulin syringe

The standard 1 mL insulin syringe is marked 0 to 100 units, so each unit is 0.01 mL. Half-mL syringes go to 50 units and are easier to read for small doses. Three-tenths mL syringes go to 30 units with even finer marks. All of them use the same rule: units are hundredths of a mL. The amount of peptide in a unit depends only on your concentration.

Subcutaneous versus intramuscular

Subcutaneous means into the fat layer, usually belly (two finger widths from the navel) or outer thigh, with a short 29 to 31 gauge needle at a 45 to 90 degree angle. It is the default for nearly every peptide. Absorption is steady and it barely hurts. Intramuscular means into muscle with a longer needle, typically 1 inch, at 90 degrees. Used for a handful of compounds and by people who want faster uptake. Either way, rotate sites so you do not build up lumps or scar tissue.

Storage

Unopened lyophilized vials: fridge is fine for months, freezer for longer. Keep them dark. Reconstituted vials: fridge only, 2 to 8 C, generally used within 4 weeks. Some peptides hold up better than that and some worse. Never leave a reconstituted vial at room temperature for long, and never freeze one.

Common mistakes

Confusing units with mcg. A unit is a volume.
Not writing down the water volume.
Shaking the vial or blasting water onto the powder.
Reusing needles. They dull after one use and carry bacteria into the vial.
Injecting cold. Let the syringe warm in your hand for a minute, it stings less.
Skipping the alcohol swab on the stopper.

Educational only. Dose ranges describe what appears in published research and community protocols. This is not medical advice and most of these compounds are not approved for human use. Talk to a clinician who knows your history.