How to Reconstitute Peptides

What you need

• The powder vial. The amount on its label is the number everything hangs off.
• Bacteriostatic (BAC) water
• A sterile syringe for mixing, and a fresh needle
• Alcohol swabs
• A pen that writes on a vial label, or a sticky label

One habit worth stealing from clinics: use one needle to draw the water and a fresh one to add it. Needles blunt and pick up contamination faster than people expect. Swapping costs almost nothing.

First, work out your water

The water amount sets the concentration, and the concentration sets your draw. Picking it on purpose takes thirty seconds: enter your vial and your dose below, choose the draw you would like, and note the water it gives you. If you already know your water amount, switch to the standard mode and it will give you the draw instead.

The steps

1. Clean the vial tops. Wash your hands. Wipe the rubber stopper of the powder vial and the water vial with an alcohol swab and let them dry before any needle goes in.
2. Draw the water. Using a fresh sterile syringe, draw the amount of bacteriostatic water you worked out for your mix.
3. Add the water slowly, down the wall. Put the needle into the powder vial and aim the stream at the inside glass wall, not straight onto the powder. Add the water slowly. A hard jet onto the powder is what makes foam.
4. Swirl gently, never shake. Roll or swirl the vial gently until the powder dissolves. Shaking makes foam and is the most common handling mistake.
5. Wait until it is fully clear. Some powders take a few minutes. The liquid should be completely clear, with nothing floating in it, before it is used or stored.
6. Label the vial. Write the date you mixed it and the concentration (the vial amount divided by the water) on the vial. An unlabelled vial becomes a guessing game within a week.

That is the whole process. Everything else on this page is about the ways it goes wrong, which are few, specific and avoidable.

How vials get ruined

Shaking is the classic. It foams the liquid, and foam takes ages to settle, and none of it helps the powder dissolve any faster. Swirl, roll, wait. If you take one thing from this page, take that.

Firing the water straight onto the powder cake does similar damage. A hard jet foams the mix and blasts the powder around the vial. Aim at the glass wall and let the water slide down and meet the powder gently.

Heat is another shortcut that is not one. People warm vials under taps and on radiators to speed dissolving. Warmth does not help, and powders are not improved by it. Time does the job heat pretends to do.

Then there are the quiet ones. Reusing a needle or syringe because it "looks clean". Using whatever water is in the kitchen because the proper vial is in another room. And the most common of all: not labelling the vial. Two weeks later you are holding a clear liquid of unknown strength and unknown age, and no memory in the world reconstructs what you mixed. Thirty seconds with a pen, at the time, prevents all of it.

Guessing the water belongs on this list too. An unplanned mix means every unit number you use afterwards is built on a number you never actually decided.

If something looks wrong

Foam is the least worrying sight. It usually just means the water went in too fast. Stand the vial in the fridge and leave it alone. It settles.

Slow dissolving is next. Some powders take a few minutes, some longer, with an occasional gentle swirl. Slow is normal. Heat and violence are still not the answer.

Cloudiness that will not clear, or particles floating in the liquid, is different. A properly mixed vial is clear. Treat a vial that stays cloudy as one to discard, not one to rescue. The dating rules in the next section assume a vial that looks right in the first place.

Storage facts

A mixed vial is dated 28 days from the day it is first punctured. That figure comes from the US Pharmacopeia's beyond-use dating for multi-dose vials, and it stands unless the manufacturer of your specific product gives a different period. Mixed vials live in the fridge, at 2 to 8 °C. Do not freeze a mixed vial. Freezing is for the dry powder stage, not the liquid.

Unmixed powder follows its own label. Dry powder keeps far longer than mixed liquid, which is exactly why the 28 day clock only starts when the water goes in. Whatever period the maker printed is the one to follow for the powder.

BAC water itself stays out of the fridge. The manufacturer's labelling says to store it at room temperature, 20 to 25 °C. Once you puncture its vial, the same 28 day dating applies to it as to anything else multi-dose.

And at any age, mixed or not: liquid that stays cloudy, anything visible floating in it, a change of colour, or a damaged stopper all mean the vial is done. Dating rules never rescue a vial that looks wrong.

Every fact in this section is sourced on the Methodology page.