How to Reconstitute Peptides: Step-by-Step

Reconstitution is just dissolving a powdered compound and doing two lines of math. This guide covers supplies, technique, the arithmetic, and the four mistakes that waste vials. Educational only — always follow the instructions supplied with your product.

Supplies

Your peptide vial (lyophilized powder or premixed liquid)
Diluent — for multi-use vials this is usually bacteriostatic water; some products specify otherwise
Alcohol swabs
A mixing/drawing syringe (1 mL or 3 mL) and your injection syringe — most people use 100U or 40U insulin syringes (syringe chart here)
A way to label the vial with the date you opened it

Step by step

1. Sanitize

Swab both stoppers with alcohol and let them air-dry. Alcohol needs a few seconds of contact time to actually work.

2. Add the diluent slowly, down the wall

Draw your planned diluent volume, then inject it slowly so it runs down the inside glass wall onto the powder — don't jet it straight down onto the compound. Foaming and splashing both stress the product.

3. Let it dissolve — swirl, never shake

Most compounds dissolve on their own in a few minutes. If not, swirl or roll the vial gently. Shaking can shear and degrade the compound.

4. Do the math — every vial, every time

Two lines:

concentration = vial strength ÷ diluent volume
draw = target dose ÷ concentration

Example: 10 mg vial + 2 mL diluent = 5 mg/mL. A 1 mg target → 0.2 mL → 20 units on a 100U insulin syringe. Run your own numbers in the free reconstitution calculator — it shows the fill line on a syringe diagram and blocks over-ranges.

5. Label, store, track

Write the date you opened the vial on the label. Most multi-use vials follow a 28-day in-use window after opening. Track remaining volume so you reorder before you run out, not after.

The four mistakes that waste a vial

Shaking instead of swirling — agitation can degrade the compound.
Assuming the concentration carried over from your last vial. Different strength or different diluent volume = different concentration. Re-run the math.
Unit slips — mg vs mcg is 1,000×. The calculator converts mg↔mcg for you and refuses to mix IU with mass units.
No opening date on the label — which makes the 28-day rule unenforceable.

Do the math in one tap
Free calculator with a visual syringe fill line and over-range blocking.

Open the calculator

VialDose is not a medical device and does not diagnose, treat, cure, or prevent any medical condition. This guide is educational only and is not instructions for any specific product or person. Follow the handling, dilution and storage instructions supplied with your product and those given by your healthcare professional.