What is reconstitution?
Retatrutide ships as a freeze-dried (lyophilized) white powder sealed under nitrogen in a glass vial. Reconstitution is the process of dissolving that powder in a liquid carrier — in this case bacteriostatic water — so it can be drawn into a syringe and injected. The procedure is identical in principle to mixing tirzepatide, semaglutide, or any other peptide from research powder.
Two variables matter: (1) the amount of powder in the vial (5, 10, 20, or 30 mg) and (2) the amount of water you add. Their ratio determines the final concentration, which in turn determines how many syringe units equal one milligram.
How to reconstitute retatrutide — step by step
- Bring the vial to room temperature. Cold lyophilized peptide is harder to dissolve. Leave the retatrutide vial on the counter for 15–30 minutes before mixing.
- Prepare your workspace. Clean surface, unopened alcohol swabs, sealed BAC water vial, sealed syringe, sharps container within reach.
- Sanitize the tops. Remove the plastic flip-cap from both the retatrutide vial and the BAC water vial. Swab each rubber stopper with an alcohol pad. Let both air dry for a few seconds.
- Draw BAC water into the syringe. Decide your water volume (1 mL, 2 mL, or 3 mL — see table below). Invert the BAC water vial and draw the correct amount. Flick out any large air bubbles.
- Inject water slowly against the wall of the retatrutide vial. Insert the needle at a 45° angle. Do not spray water directly onto the powder pellet — this can shear peptide bonds. Let the water trickle down the inside glass wall.
- Gently swirl — never shake. Hold the vial between thumb and fingers and swirl in slow circles for 30–60 seconds. The powder should dissolve into a clear, colorless solution. If undissolved particles remain after a minute, wait 5 minutes and swirl again.
- Date the vial. Write the reconstitution date on the vial label. Reconstituted product is good for ~30 days refrigerated.
- Refrigerate. Store at 2–8 °C (36–46 °F). Do not freeze.
How much BAC water: the standard recipes
| Vial size | BAC water | Concentration | Best for |
|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | Starter dosing (0.5–2 mg) |
| 10 mg | 1 mL | 10 mg/mL | Standard — easy mg-to-units math |
| 10 mg | 2 mL | 5 mg/mL | Microdosing / finer resolution |
| 20 mg | 1 mL | 20 mg/mL | High doses in minimal volume |
| 20 mg | 2 mL | 10 mg/mL | Standard — 4 doses of 5 mg |
| 30 mg | 2 mL | 15 mg/mL | Maintenance titration |
| 30 mg | 3 mL | 10 mg/mL | Maximum safety margin on units |
Rule of thumb: pick a water volume that gives round numbers for your target dose. If you're titrating to 4 mg weekly, 10 mg/mL concentration gives you 40 units per dose (easy to read and remember). If you're microdosing at 0.5 mg, 5 mg/mL gives 10 units — much easier than 5 units on a U-100.
Common reconstitution mistakes
- Shaking the vial. Peptides are fragile. Vigorous shaking can denature the active molecule. Gentle swirling or inversion only.
- Injecting water directly onto the powder. High-velocity stream damages the peptide pellet. Always angle the needle so water runs down the vial wall.
- Using the wrong volume. Double-check BAC water volume against your target concentration. A 10 mg vial with 2 mL water (5 mg/mL) is not interchangeable with 10 mg + 1 mL (10 mg/mL) — you\'ll under-dose or over-dose by 2×.
- Not labeling. Multiple vials at different concentrations is a recipe for confusion. Label each vial with date, concentration, and intended dose.
- Leaving reconstituted product at room temp. Stability drops outside refrigeration. Refrigerate immediately after mixing.
- Using past 30 days. Even with BAC water, microbial risk and peptide degradation rise past 30 days.
How to store retatrutide
- Unreconstituted (dry powder): refrigerator ideal (2–8 °C), protected from light. Manufacturer vials tolerate short periods at room temperature during shipping.
- Reconstituted: refrigerator always. 30-day usable window. Bring to room temp 15 min before injecting to reduce sting.
- Avoid: freezing, direct sunlight, heat (car glove box, windowsill). Freezing breaks the peptide; heat accelerates degradation.
- Discard if: solution becomes cloudy, discolored, contains visible particles, or the vial is compromised.