Peptides usually arrive as a dry lyophilized powder. Before the peptide can be measured as a liquid, it needs to be reconstituted with bacteriostatic water, also called BAC water.
The most common beginner mistake is overcomplicating the math. You only need to understand three things:
How many mg are in the vial
How many mL of BAC water you added
How many units you need to draw
A standard U-100 insulin syringe follows this rule:
100 units = 1 mL
10 units = 0.10 mL
1 unit = 0.01 mL
Step 1: Find the Concentration
The formula is simple:
Peptide mg ÷ amount of BAC water added = concentration per mL
Example:
10 mg peptide ÷ 2 mL BAC water = 5 mg/mL
This means every 1 mL contains 5 mg of peptide.
Since 1 mL = 100 units, that also means:
100 units = 5 mg
10 units = 0.5 mg
20 units = 1 mg
50 units = 2.5 mg
Step 2: Determine Your Amount
Once you know the concentration, you can divide to determine the amount needed.
Example:
Your concentration is 5 mg/mL.
Your target amount is 1 mg.
1 mg ÷ 5 mg/mL = 0.2 mL
Since 1 mL = 100 units:
0.2 mL = 20 units
So at 5 mg/mL, a 1 mg amount = 20 units.
Simple Example
A 10 mg vial mixed with 2 mL BAC water gives:
10 ÷ 2 = 5 mg/mL
That means:
| Units | Amount |
|---|---|
| 5 units | 0.25 mg |
| 10 units | 0.5 mg |
| 20 units | 1 mg |
| 40 units | 2 mg |
| 50 units | 2.5 mg |
| 100 units | 5 mg |
Common Concentrations
| Vial | BAC Water Added | Concentration | 10 Units | 20 Units | 50 Units |
|---|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 0.5 mg | 1 mg | 2.5 mg |
| 10 mg | 2 mL | 5 mg/mL | 0.5 mg | 1 mg | 2.5 mg |
| 15 mg | 3 mL | 5 mg/mL | 0.5 mg | 1 mg | 2.5 mg |
| 30 mg | 3 mL | 10 mg/mL | 1 mg | 2 mg | 5 mg |
| 60 mg | 3 mL | 20 mg/mL | 2 mg | 4 mg | 10 mg |
Easy Rule to Remember
First, calculate the concentration:
Peptide mg ÷ BAC water mL = mg per mL
Then remember:
1 mL = 100 units
From there, divide based on the amount you need.
Example:
10 mg peptide + 2 mL BAC = 5 mg/mL
So:
5 mg = 100 units
1 mg = 20 units
0.5 mg = 10 units
0.25 mg = 5 units
Handling and Sanitation
Before handling any vial, clean your workspace and wash your hands. Use alcohol wipes and handle everything carefully.
A basic clean process:
Check the vial for the correct label, seal, and any visible damage.
Wipe the rubber stopper with alcohol and let it dry.
Draw the BAC water slowly.
Add the BAC water gently into the vial, ideally letting it run down the inside wall.
Do not blast the powder directly.
Swirl or roll the vial gently until dissolved.
Do not shake aggressively.
Label the vial with the reconstitution date and concentration.
Store properly after mixing.
Avoid reusing syringes, leaving needles in vials, or using any vial that looks cloudy, discolored, cracked, contaminated, or questionable.
Storage Basics
Most peptides are sensitive to heat, light, and repeated handling. Once reconstituted, they should generally be kept cold, protected from light, and handled cleanly.
Keep the vial refrigerated after mixing.
Avoid heat exposure.
Avoid direct sunlight.
Do not freeze unless specifically instructed.
Keep the vial sealed when not in use.
Track the date it was mixed.
Know the concentration before drawing.
The key is simple: know how much peptide is in the vial, know how much BAC water was added, calculate the concentration, and convert mL to units.
Peptide mg ÷ BAC water mL = concentration per mL.
1 mL = 100 units.
Once you understand that, the math becomes simple.
For Research Use Only. Educational content only.