Peptide Reconstitution Calculator

Below are step-by-step calculation walkthroughs for some of the most commonly reconstituted research peptides. Each example shows the exact math behind the calculator's output so you can verify the numbers yourself.

BPC-157 — 5 mg Vial, 250 mcg Dose

BPC-157 is one of the most commonly reconstituted peptides. A standard 5 mg vial with 2 mL of bacteriostatic water gives you a manageable concentration:

• Vial size: 5 mg (5,000 mcg)
• BAC water added: 2 mL
• Concentration: 5,000 mcg ÷ 2 mL = 2,500 mcg/mL
• Draw for 250 mcg dose: 250 ÷ 2,500 = 0.1 mL = 10 units on a U-100 syringe
• Doses per vial: 5,000 ÷ 250 = 20 doses

At twice-daily dosing, one vial lasts 10 days. For a 4-week protocol you'll need approximately 3 vials.

Semaglutide — 5 mg Vial, 0.25 mg Starter Dose

Semaglutide uses milligram-level dosing with a slow titration schedule:

• Vial size: 5 mg (5,000 mcg)
• BAC water added: 2 mL
• Concentration: 5,000 mcg ÷ 2 mL = 2,500 mcg/mL
• Draw for 0.25 mg (250 mcg) dose: 250 ÷ 2,500 = 0.1 mL = 10 units
• Doses per vial at 0.25 mg: 5,000 ÷ 250 = 20 weekly doses (about 5 months at starter dose)

As you titrate up to 0.5 mg and beyond, each dose draws more solution and the vial depletes faster. At 1 mg/week, you'll get 5 weekly doses per vial.

CJC-1295 — 2 mg Vial, 100 mcg Dose

• Vial size: 2 mg (2,000 mcg)
• BAC water added: 1 mL
• Concentration: 2,000 mcg ÷ 1 mL = 2,000 mcg/mL
• Draw for 100 mcg dose: 100 ÷ 2,000 = 0.05 mL = 5 units
• Doses per vial: 2,000 ÷ 100 = 20 doses

Tip: when your draw volume falls below 5 units, consider adding more water during reconstitution to improve measurement accuracy.

For a full walkthrough including sterile technique and storage, read our How to Reconstitute Peptides step-by-step guide.

• Spraying water directly onto the powder. Always aim the stream of bacteriostatic water down the inside wall of the vial, letting it flow gently over the lyophilized cake. Spraying directly onto the powder can denature fragile peptide bonds.
• Using sterile water instead of bacteriostatic water for multi-use vials. Sterile water for injection (SWFI) contains no preservative and should only be used for single-dose applications. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits microbial growth across multiple draws over 28 days.
• Shaking the vial to dissolve the peptide. Vigorous shaking introduces air bubbles and can denature the peptide through mechanical stress. Instead, gently swirl or roll the vial between your palms until the solution is clear.
• Forgetting to swab the vial stopper. Always wipe both the peptide vial and BAC water vial with a 70% isopropyl alcohol swab before piercing. This simple step prevents contamination that could degrade the peptide or cause infection.
• Not labeling the reconstituted vial. After mixing, write the peptide name, concentration (mcg per unit or per mL), date of reconstitution, and discard date on the vial. Unlabeled vials lead to dosing errors.
• Using the wrong syringe scale. Insulin syringes come in U-100 (100 units/mL) and U-40 (40 units/mL) formats. Most peptide dosing references assume U-100 syringes. Using U-40 syringes without adjusting the math will result in a 2.5x overdose.

This calculator handles the math — but if you want a complete walkthrough of the reconstitution process including sterile technique, solvent selection, equipment, and storage instructions, see our dedicated guide:

How to Reconstitute Peptides — Complete Step-by-Step Guide →

It covers everything from swabbing vial tops to proper refrigerated storage after mixing, with common mistakes to avoid at each step. For compound-specific dosage ranges, use the Dosage Calculator. To figure out how much BAC water to purchase, try the BAC Water Calculator.