Peptide Reconstitution 101: Step-by-Step Guide With Dosing Math
Every research peptide arrives as a lyophilized (freeze-dried) powder in a sealed vial. Before it can be used, it needs to be reconstituted — dissolved in bacteriostatic water (BAC water) to create an injectable solution. This process is straightforward once you understand the math and the technique, but getting it wrong can destroy an expensive vial or produce inaccurate dosing.
This is the complete step-by-step reconstitution guide, with worked examples for the most popular peptides.
What You Need
| Item | Purpose | Where to Get It |
|---|---|---|
| Bacteriostatic water (BAC water) | Solvent for reconstitution (contains 0.9% benzyl alcohol as preservative) | Amazon, medical supply stores |
| Insulin syringes (29-31 gauge) | Measuring and drawing the solution | Amazon, pharmacies |
| Alcohol swabs | Sterilizing vial tops before piercing | Amazon, pharmacies |
| Your peptide vial | The lyophilized peptide to reconstitute | Verified suppliers (see below) |
⚠ BAC Water vs Sterile Water: Always use bacteriostatic water for peptides that will be used over multiple days. The benzyl alcohol preservative prevents bacterial growth in the reconstituted solution, giving it a shelf life of ~28 days refrigerated. Plain sterile water has no preservative and should only be used for single-use preparations.
Step-by-Step Reconstitution
Step 1: Gather and prepare
Wash hands thoroughly. Lay out your vial, BAC water, syringe, and alcohol swabs on a clean surface. Allow the peptide vial to reach room temperature if it’s been refrigerated (5-10 minutes).
Step 2: Swab the vial tops
Wipe the rubber stopper of both the peptide vial and the BAC water vial with an alcohol swab. Let air dry for 10-15 seconds.
Step 3: Draw BAC water
Using an insulin syringe, draw your desired amount of BAC water. The amount you add determines the concentration of your solution (see math section below). A common choice is 1 mL (100 units on an insulin syringe) for easy math.
Step 4: Add water to the peptide vial
Insert the needle through the rubber stopper of the peptide vial. Do NOT squirt the water directly onto the powder. Instead, aim the stream at the inside wall of the vial and let it trickle down slowly. This prevents damaging the peptide’s molecular structure through excessive agitation.
Step 5: Gently swirl — never shake
Once the water is added, gently roll or swirl the vial between your fingers until the powder is fully dissolved. This may take 1-3 minutes. Never shake a peptide vial — shaking can denature (damage) the peptide chains through physical stress.
Step 6: Refrigerate
Once reconstituted, store the vial in the refrigerator at 36-46°F (2-8°C). A reconstituted peptide in BAC water is stable for approximately 28 days. Keep it away from light.
The Reconstitution Math
The formula is simple:
Concentration = Peptide Amount (mcg) ÷ BAC Water Volume (mL)
Then: Units to Draw = (Desired Dose ÷ Concentration) × 100
(Because 1 mL = 100 units on a standard insulin syringe)
Worked Example: BPC-157 (5 mg vial)
You have a 5 mg (5,000 mcg) vial of BPC-157 and you want to dose 250 mcg per day.
- Add 2 mL of BAC water to the vial
- Concentration: 5,000 mcg ÷ 2 mL = 2,500 mcg/mL
- For a 250 mcg dose: (250 ÷ 2,500) × 100 = 10 units on the syringe
- Vial lasts: 5,000 ÷ 250 = 20 days
Worked Example: Semaglutide (5 mg vial)
You have a 5 mg (5,000 mcg) vial of semaglutide and you want to dose 250 mcg per week (starting dose).
- Add 2 mL of BAC water
- Concentration: 5,000 mcg ÷ 2 mL = 2,500 mcg/mL
- For a 250 mcg dose: (250 ÷ 2,500) × 100 = 10 units
- Vial lasts: 5,000 ÷ 250 = 20 weeks (well within 28-day reconstituted shelf life, so consider using two vials)
Worked Example: CJC-1295/Ipamorelin (Blend, 5 mg each)
Blend vial with 5 mg CJC-1295 + 5 mg Ipamorelin. Target dose: 300 mcg of each, 5 days per week.
- Add 2 mL of BAC water
- Each compound: 5,000 mcg ÷ 2 mL = 2,500 mcg/mL
- For 300 mcg: (300 ÷ 2,500) × 100 = 12 units
- Vial lasts: 5,000 ÷ 300 = ~16.7 doses = ~3.3 weeks at 5x/week
Quick Reference: Common Peptides
| Peptide | Typical Vial | Common Dose | BAC Water | Units/Dose | Vial Lasts |
|---|---|---|---|---|---|
| BPC-157 | 5 mg | 250 mcg/day | 2 mL | 10 units | 20 days |
| TB-500 | 5 mg | 750 mcg 2x/wk | 2 mL | 30 units | ~3 weeks |
| Semaglutide | 5 mg | 250 mcg/wk | 2 mL | 10 units | 20 weeks* |
| GHK-Cu | 50 mg | 1-2 mg/day | 2 mL | 4-8 units | 25-50 days |
| CJC-1295/Ipa | 5/5 mg | 300 mcg 5x/wk | 2 mL | 12 units | ~3 weeks |
| Selank | 5 mg | 300 mcg/day | 2 mL | 12 units | ~16 days |
*Semaglutide reconstituted shelf life is ~28 days; for longer protocols, use smaller vial amounts or split across vials.
Where to Source Peptides and Supplies
BioPure Peptides
Code: POWER40+ peptides including BPC-157, TB-500, GHK-Cu, Semaglutide, CJC-1295/Ipa. Third-party HPLC tested with COAs.
Shop BioPure →Midwest Peptide
Code: POWER — 10% Off32 products with COAs on every page. Free shipping on all orders. Serialized vial tracking.
Shop Midwest →Apollo Peptide Sciences
Verified COAsBPC-157, TB-500, Semaglutide, CJC-1295 and more with independent testing.
Shop Apollo →Amino Club
Code: POWER — 20% Off First OrderHPLC + Mass Spec tested. In-house manufacturing with documented QC. FedEx shipping.
Shop Amino Club →Offline Peptides
Research SupplierResearch peptide supplier with direct-to-customer fulfillment.
Visit Store →Frequently Asked Questions
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