Knowing how to reconstitute retatrutide correctly is the difference between a vial that stays stable for weeks and one that degrades in days. The peptide arrives as a freeze dried powder, so it needs to go back into solution before it can be measured or stored. The process takes about five minutes. However, a few details matter more than people expect: the water you use, how you add it, and what you do with the vial afterwards. This guide walks through each step in order.

Reta Bangkok supplies retatrutide strictly for laboratory research. This guide describes standard lab handling of a lyophilised peptide. It is not medical advice and does not describe use in humans.

What you need

• One vial of lyophilised retatrutide (10 mg, 20 mg, 30 mg, 40 mg or 60 mg)
• One vial of bacteriostatic water (0.9% benzyl alcohol)
• A sterile syringe with a needle, for transferring the water
• Alcohol swabs
• A refrigerator at 2 to 8 °C for storage afterwards

One point before you start: use bacteriostatic water, not sterile water. Sterile water contains no preservative, so a vial you draw from more than once can grow bacteria within a few days. Bacteriostatic water contains 0.9% benzyl alcohol, which prevents that and keeps a multi use vial safe for around four weeks after reconstitution. Both are available in Thailand, but only one of them belongs in a vial you plan to keep.

How much water to add

There is no single correct volume. More water gives a more dilute solution, which is easier to measure in small amounts. Less water gives a concentrated solution, which fits more of the peptide into a small vial. For most research work, 1 ml to 2 ml of bacteriostatic water per vial is the usual range. The table below shows the resulting concentration for each vial size we stock.

Vial	1 ml water	2 ml water	3 ml water
10 mg	10 mg/ml	5 mg/ml	3.33 mg/ml
20 mg	20 mg/ml	10 mg/ml	6.67 mg/ml
30 mg	30 mg/ml	15 mg/ml	10 mg/ml
40 mg	40 mg/ml	20 mg/ml	13.33 mg/ml
60 mg	60 mg/ml	30 mg/ml	20 mg/ml

If you want the exact syringe fill for a given concentration, our reconstitution calculator does the arithmetic for you. Enter the vial size and the water volume, and it returns the concentration and the units per measurement.

Step by step

1. Let the vial reach room temperature

Take the retatrutide vial out of the refrigerator and leave it on the bench for 10 to 15 minutes. Adding water to a cold vial can cause condensation inside the glass and makes the powder dissolve more slowly. Meanwhile, wash your hands and clear a clean working surface.

2. Swab both vials

Remove the plastic flip cap from the retatrutide vial and from the bacteriostatic water. Then wipe both rubber stoppers with an alcohol swab and let them air dry for a few seconds. Do not touch the stoppers afterwards.

3. Draw up the water

Pull the syringe plunger back to the volume of water you intend to use, so the syringe holds that much air. Push the needle through the stopper of the water vial and inject the air. This equalises the pressure and makes the water easier to draw. Next, turn the vial upside down and pull the plunger back slowly to the volume you want. Tap out any air bubbles and withdraw the needle.

4. Add the water slowly, down the side of the glass

This is the step that matters most. Push the needle through the retatrutide stopper at an angle, so the tip rests against the inside wall of the vial. Then press the plunger slowly, letting the water run down the glass rather than spraying directly onto the powder. Peptide chains are fragile, and a hard jet of water onto the cake can damage them. Take 20 to 30 seconds over this, not two.

5. Swirl, never shake

Withdraw the needle and gently roll or swirl the vial between your fingers. Shaking creates foam and shears the peptide, so avoid it entirely. Retatrutide dissolves readily. Within a minute or two, the solution should be completely clear with no visible particles. If a little powder clings to the glass, set the vial down for five minutes and swirl again. Do not warm it.

6. Label and refrigerate

Write the reconstitution date and the concentration on the vial. Then place it in the refrigerator at 2 to 8 °C, upright, away from the door so it is not exposed to temperature swings every time the fridge opens. From this point the solution is stable for about four weeks. Light and heat degrade it, so keep it in its box or a dark container.

Common mistakes

• Using sterile water for a multi use vial. It has no preservative. Use bacteriostatic water instead.
• Shaking the vial. Foam is a sign of damaged peptide. Swirl gently.
• Spraying water directly onto the powder. Run it down the glass.
• Leaving the solution at room temperature. Once reconstituted, it belongs in the fridge.
• Freezing the solution. Freeze thaw cycles break peptides down. Refrigerate only.
• Not labelling the vial. After a week, two vials look identical. Write the date and concentration on every one.

How long reconstituted retatrutide lasts

Reconstituted with bacteriostatic water and kept at 2 to 8 °C, retatrutide remains stable for approximately four weeks. The lyophilised powder, by contrast, keeps for a year or more in the refrigerator and considerably longer in a freezer at minus 20 °C. For that reason, only reconstitute what you expect to use within a month, and leave the remaining vials sealed. For storage details in full, see our guide on retatrutide storage and handling.

Retatrutide and bacteriostatic water at Reta Bangkok

We stock retatrutide in five vial sizes and bacteriostatic water in 3 ml and 10 ml vials. An independent lab tests every batch, and the certificate of analysis sits on each product page. Orders placed before 3 pm go out the same day in Bangkok, and we ship nationwide across Thailand.

All products on Reta Bangkok are for laboratory research use only, not for human or veterinary use.