Guides/How to Calculate Peptide Doses

How to Calculate Peptide Doses

A step-by-step breakdown of peptide dose calculation — from vial size to syringe draw units. Includes the free Protocol calculator so you never have to do the math manually.

Applies to BPC-157, TB-500, GHK-Cu, Semaglutide, Ipamorelin, CJC-1295, and all other lyophilized peptides.

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Skip the math — use the free calculator

Protocol's peptide calculator handles all of this automatically — including Custom Draw mode where you enter your preferred units first. Use it free →

The Step-by-Step Calculation

1

Know your vial size in mg

Lyophilized peptide vials are labeled in milligrams (mg). Convert to micrograms (mcg) for the math: 1mg = 1,000mcg. A 5mg vial contains 5,000mcg.

5mg vial = 5,000mcg total peptide
2

Decide how much BAC water to add

The amount you add determines your concentration. More water = lower concentration = more units per dose. Less water = higher concentration = fewer units per dose.

2mL BAC water into 5mg vial
3

Calculate concentration

Concentration = total peptide mcg ÷ BAC water mL. This tells you how many mcg are in every mL of reconstituted solution.

5,000mcg ÷ 2mL = 2,500mcg/mL
4

Calculate your draw volume

Draw volume = target dose ÷ concentration. This tells you how many mL to draw for your dose.

250mcg ÷ 2,500mcg/mL = 0.1mL
5

Convert to syringe units

For U-100 insulin syringes (the standard for peptide injections): units = draw volume × 100. Each unit = 0.01mL.

0.1mL × 100 = 10 units

The Complete Formula

Concentration = Vial (mg × 1000) ÷ BAC water (mL) → mcg/mL
Draw volume = Dose (mcg) ÷ Concentration (mcg/mL) → mL
Draw units = Draw volume (mL) × Syringe units/mL → units
Doses per vial = Total peptide (mcg) ÷ Dose (mcg)

Worked Example: BPC-157

Vial size5mg BPC-157
BAC water added2mL
Target dose250mcg
SyringeU-100 insulin syringe
Concentration5,000mcg ÷ 2mL = 2,500mcg/mL
Draw volume250mcg ÷ 2,500mcg/mL = 0.1mL
Draw units0.1mL × 100 = 10 units
Doses per vial5,000mcg ÷ 250mcg = 20 doses

Custom Draw: Working Backwards

If you always want to draw exactly 10 units, how much BAC water should you add?

Draw volume = 10 units ÷ 100 = 0.1mL
Needed concentration = 250mcg ÷ 0.1mL = 2,500mcg/mL
BAC water to add = 5,000mcg ÷ 2,500mcg/mL = 2mL

Protocol's Custom Draw mode does this automatically.

FAQ

How do I calculate peptide doses?+
To calculate: (1) Divide total peptide mcg by BAC water mL to get concentration. (2) Divide target dose mcg by concentration to get draw volume mL. (3) Multiply draw volume by syringe units/mL (100 for U-100) to get draw units. Example: 5mg vial + 2mL BAC = 2500mcg/mL. For 250mcg dose: 250 ÷ 2500 = 0.1mL = 10 units on U-100.
What units do I use to draw peptides?+
Most peptide users use U-100 insulin syringes where 1mL = 100 units. Each unit equals 0.01mL. At 2500mcg/mL concentration, 1 unit delivers 25mcg.
How much BAC water should I add to my peptide vial?+
It depends on your target dose and preferred draw amount. Common protocols add 1-2mL to a 5mg vial, yielding 5000-2500mcg/mL. Use Custom Draw mode in Protocol's calculator: enter your preferred units and it calculates the exact BAC water volume to add.
What is the formula for peptide reconstitution?+
Concentration (mcg/mL) = Total peptide (mcg) ÷ BAC water (mL). Draw volume (mL) = Target dose (mcg) ÷ Concentration (mcg/mL). Draw units = Draw volume (mL) × syringe units per mL.

Free Peptide Calculator — No Math Required

Enter your vial, dose, and BAC water. Get draw units instantly. Custom Draw mode included free.

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