TOOLS

Peptide Calculator

Reconstitution volumes, exact syringe doses, and vial supply — calculated instantly for insulin, standard, and tuberculin syringes.

Research use only. Not approved for human therapeutic use in most jurisdictions. Always consult a licensed medical professional.

Vial setup

Lyophilized powder

Lyophilized
mg
Bacteriostatic
mL

Dosing

Per injection

Per injection
mcg
Supply calc

Syringe type

Select your syringe

1 mL capacity100u max0.01 mL per unit

Syringe guide

100u / 1 mL — Insulin (U-100)

10.0u
0102030405060708090100

Fits — 10% of this syringe's capacity used

DRAW TO
10.0
units (100u max)
VOLUME
0.1000
mL

Vial summary

CONCENTRATION
2.50
mg/mL
DOSE
250
mcg
DOSES / VIAL
20.0
doses
VIAL SUPPLY
20.0
days
at 1× per day

STEP-BY-STEP

  1. 1

    Draw 2 mL of bacteriostatic water into a syringe

  2. 2

    Inject slowly into the 5 mg peptide vial — aim at the glass wall, not the powder

  3. 3

    Gently swirl (never shake) until fully dissolved

  4. 4

    Solution concentration is now 2500.0 mcg/mL

  5. 5

    For 250 mcg dose: draw to 10.0 units on a 100u insulin syringe

  6. 6

    Refrigerate at 2–8°C. Discard after 28–30 days.

Reference table5 mg / 2 mL BAC water
DoseVolume (mL)100u50u30uDoses
50 mcg0.02002.02.02.0100
100 mcg0.04004.04.04.050
200 mcg0.08008.08.08.025
250 mcg0.100010.010.010.020
300 mcg0.120012.012.012.016.666666666666668
400 mcg0.160016.016.016.012.5
500 mcg0.200020.020.020.010
750 mcg0.300030.030.030.06.666666666666667
1000 mcg0.400040.040.040.05
2000 mcg0.800080.080.080.02.5

Click any row to apply that dose above

FAQ

Peptide Calculator — Common Questions

How do I calculate peptide dosage from a vial?

Divide the vial peptide amount (in mcg) by the volume of BAC water added (in mL) to get the concentration in mcg/mL. Then divide your desired dose (mcg) by the concentration to get the injection volume in mL. Example: 5 mg vial + 2 mL BAC water = 2,500 mcg/mL concentration. For a 250 mcg dose: 250 ÷ 2,500 = 0.1 mL per injection.

How many units on an insulin syringe for peptides?

On a U-100 insulin syringe, 1 unit = 0.01 mL. Multiply your injection volume (mL) by 100 to get units. Example: 0.1 mL dose = 10 units on a 100u insulin syringe. For a 250 mcg dose from a 5 mg / 2 mL vial (2,500 mcg/mL): draw to the 10-unit mark on a standard insulin syringe.

How much BAC water should I add to reconstitute a peptide?

The most common reconstitution ratio is 1–2 mL of bacteriostatic water per 5 mg vial. Using 2 mL gives a concentration of 2,500 mcg/mL, which keeps injection volumes in a practical range (0.04–0.4 mL) for typical research doses of 100–1,000 mcg. Smaller volumes create higher concentrations; larger volumes make measuring small doses easier.

What is bacteriostatic water and why is it used?

Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol, which prevents microbial growth. Unlike sterile water, BAC water preserves reconstituted peptides for 28–30 days when refrigerated at 2–8°C. It is the standard diluent for lyophilized research peptides. Never use tap water, distilled water, or saline for peptide reconstitution.

How long does a reconstituted peptide vial last?

Reconstituted peptides dissolved in bacteriostatic water last 28–30 days when stored at 2–8°C (standard refrigerator). Lyophilized (freeze-dried) powder vials last 1–2 years when stored at -20°C. Never freeze a reconstituted (liquid) peptide — this degrades the peptide structure. Discard any solution showing cloudiness, color change, or particulates.

BPC-157 dosage calculator — how do I dose 250 mcg?

For BPC-157: reconstitute a 5 mg vial with 2 mL bacteriostatic water (concentration = 2,500 mcg/mL). For a 250 mcg dose, draw to 0.1 mL (10 units on a 100u insulin syringe). For 500 mcg, draw to 0.2 mL (20 units). Inject subcutaneously into the abdomen. Standard research protocol is 250–500 mcg once or twice daily.

How do I convert mcg to mL for peptide injections?

To convert mcg to mL: divide the dose in mcg by the peptide concentration in mcg/mL. The concentration depends on how much BAC water you added. The peptide calculator above does this automatically — enter your vial size (mg), BAC water volume (mL), and desired dose (mcg) to get the exact mL and insulin-unit values.

What syringe size should I use for peptide injections?

Most researchers use U-100 insulin syringes (29–31 gauge, 0.5–1 mL capacity) for subcutaneous peptide injections. The 100-unit / 1 mL insulin syringe is the most versatile for doses reconstituted at 2,500 mcg/mL. For very small volumes (< 0.1 mL), a tuberculin syringe with 0.01 mL graduations improves precision. Standard 1 mL syringes are suitable for higher-volume protocols.

How the Peptide Reconstitution Calculator Works

The PeptideWiki peptide calculator uses the standard reconstitution formula: Concentration (mcg/mL) = Peptide (mcg) ÷ BAC Water (mL). Your injection volume is then Volume (mL) = Dose (mcg) ÷ Concentration (mcg/mL).

For insulin syringes (U-100), the calculator converts mL to units automatically: Units = Volume (mL) × 100. The visual syringe gauge shows exactly where to draw the plunger, and an overflow warning appears if your dose exceeds the selected syringe capacity.

The supply calculator estimates how many doses and days your vial will last based on your dosing frequency — supporting daily, twice-daily, three-times-daily, weekly, and fortnightly protocols. The built-in dilution calculator (C₁V₁ = C₂V₂) helps when working with high-concentration stock solutions that need further dilution.