How to Reconstitute Peptides
To reconstitute a peptide, slowly inject bacteriostatic water down the inside wall of the lyophilized vial, let it dissolve without shaking, and calculate your dose in insulin-syringe units from the resulting concentration. A 5mg vial with 2 ml of water gives 2.5 mg/ml, so 10 units = 250 mcg.
Video explanation
Third-party educational video. Not affiliated with PepIQ.
Supplies
- Lyophilized peptide vial
- Bacteriostatic water (0.9% benzyl alcohol) — not sterile water, which has no preservative
- Insulin syringes (U-100, 0.5 ml or 1 ml, 29–31 gauge) for drawing doses
- A larger syringe (3 ml) or a second insulin syringe for adding water
- Alcohol swabs
Step-by-step guide
- Decide how much water to add. More water = lower concentration = larger, easier-to-measure doses. reconstitution calculator. For most 5mg vials, 2 ml is standard.
- Swab both vial tops with alcohol and let dry.
- Draw the bacteriostatic water into your syringe. Inject a little air into the water vial first to equalize pressure.
- Inject the water into the peptide vial slowly, angling the needle so water runs down the glass wall rather than spraying onto the powder. Some peptides are fragile; forceful spraying can degrade them.
- Let it dissolve. Gently swirl or roll the vial. Do not shake. Most peptides clear in 1–5 minutes; some take longer. A cloudy solution that doesn't clear may indicate a problem with the product.
- Calculate your dose in units. Concentration (mg/ml) ÷ 100 = mg per unit on a U-100 syringe. Example: 2.5 mg/ml ÷ 100 = 0.025 mg (25 mcg) per unit.
- Draw your dose with a fresh insulin syringe, tapping out air bubbles.
- Label the vial with the date reconstituted and concentration. Refrigerate.
Units math cheat sheet
| Vial | Water | Concentration | mcg per unit |
|---|---|---|---|
| 5 mg | 1 ml | 5 mg/ml | 50 |
| 5 mg | 2 ml | 2.5 mg/ml | 25 |
| 5 mg | 3 ml | 1.67 mg/ml | 16.7 |
| 10 mg | 2 ml | 5 mg/ml | 50 |
| 10 mg | 4 ml | 2.5 mg/ml | 25 |
| 3 mg | 1.2 ml | 2.5 mg/ml | 25 |
Common mistakes
- Using sterile water instead of bacteriostatic water (solution won't stay safe for multi-dose use)
- Shaking the vial
- Forgetting the syringe is U-100 (100 units = 1 ml), then confusing units with ml
- Not writing the concentration on the vial
Storage after reconstitution
Refrigerate at 2–8°C, keep out of light, use within roughly 4 weeks. Do not freeze.
Frequently asked questions
Can I use sterile water?
Only for a single-use vial consumed immediately. For multi-dose vials use bacteriostatic water.
How much bacteriostatic water for a 5mg vial?
2 ml is the most common choice; 1 ml if you want a more concentrated solution.
How many units in 1 ml?
100 on a U-100 insulin syringe.
How long is a reconstituted peptide good for?
About 4 weeks refrigerated, depending on the peptide.
What if the powder doesn't dissolve?
Let it sit 10–15 minutes. If it stays cloudy or has particles, do not use it.
Save every vial's concentration and dose in PepIQ so you never redo the math.
Use PepIQ to scan vials and access the verified peptide shop.
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