How to Reconstitute Peptides: A Step-by-Step Reference

Reconstitution is where most first-time buyers mess up dosing. This is the reference we use ourselves.

What you need

• The lyophilized peptide vial (kept refrigerated until use)
• Bacteriostatic water (0.9% benzyl alcohol) — never plain sterile water for multi-use vials
• 3 mL syringe with 21G needle for drawing water
• Insulin syringes (0.5 mL, 29–31G) for dosing
• Alcohol swabs

Step-by-step

• 1. Let the peptide vial reach room temperature (~15 minutes on the counter).
• 2. Swab both rubber stoppers with alcohol.
• 3. Draw your chosen volume of BAC water into the 3 mL syringe.
• 4. Angle the needle against the inside wall of the peptide vial and let the water run down slowly — do not shoot it directly onto the powder.
• 5. Do not shake. Gently swirl. The powder should dissolve within 30–60 seconds.
• 6. Label the vial with reconstitution date and concentration.
• 7. Refrigerate (2–8°C).

The dosing math you actually need

Concentration (mg/mL) = vial size (mg) ÷ water added (mL). To pull a dose in units on an insulin syringe: (desired dose in mg ÷ concentration) × 100.

Storage

• Reconstituted with BAC water: 28–30 days refrigerated for most peptides.
• GLP-1s (semaglutide, tirzepatide, retatrutide): up to 8 weeks refrigerated.
• Never freeze reconstituted peptides — freeze/thaw destroys peptide bonds.