Peptide Dosing Calculator Guide

Understanding Peptide Dosing

Accurate dosing is fundamental to peptide protocols. Underdosing wastes product and yields poor results; overdosing risks side effects and unnecessary expense. This guide teaches you to calculate precise doses regardless of peptide type, vial size, or reconstitution volume.

The Three Variables You Need

Every peptide dose calculation requires three pieces of information:

1. Peptide amount in vial (in mg or mcg)
2. Bacteriostatic water added (in mL)
3. Target dose (in mcg or mg)

From these, you can calculate the exact volume to inject.

The Master Formula

Dose (mcg) ÷ Concentration (mcg/mL) = Volume to inject (mL)

Step-by-Step

Step 1: Calculate concentration Concentration = Peptide amount ÷ Water added

Example: 5 mg peptide in 2 mL water Concentration = 5 mg ÷ 2 mL = 2.5 mg/mL = 2,500 mcg/mL

Step 2: Calculate injection volume Volume = Target dose ÷ Concentration

Example: Target dose is 250 mcg Volume = 250 mcg ÷ 2,500 mcg/mL = 0.1 mL

Step 3: Convert to syringe units On a standard U-100 insulin syringe: 0.1 mL = 10 units

Unit Conversions

Weight Conversions

Quick conversion:

• mg to mcg: Multiply by 1,000
• mcg to mg: Divide by 1,000

Volume Conversions (Insulin Syringes)

Standard U-100 insulin syringes are marked in "units":

• 100 units = 1 mL
• 50 units = 0.5 mL
• 10 units = 0.1 mL
• 1 unit = 0.01 mL

Common syringe sizes:

• 1 mL (100 unit) — For larger volume injections
• 0.5 mL (50 unit) — Most common for peptides
• 0.3 mL (30 unit) — For very small doses, better precision

Worked Examples by Peptide

BPC-157 Example

Given:

• Vial contains: 5 mg BPC-157
• Water added: 2 mL bacteriostatic water
• Target dose: 250 mcg twice daily

Calculation:

Step 1: Convert to same units 5 mg = 5,000 mcg

Step 2: Calculate concentration 5,000 mcg ÷ 2 mL = 2,500 mcg/mL

Step 3: Calculate injection volume 250 mcg ÷ 2,500 mcg/mL = 0.1 mL = 10 units

Result: Draw to the 10-unit mark for each 250 mcg dose.

TB-500 Example

Given:

• Vial contains: 5 mg TB-500
• Water added: 1 mL bacteriostatic water
• Target dose: 2.5 mg twice weekly (loading phase)

Calculation:

Step 1: Concentration 5 mg ÷ 1 mL = 5 mg/mL

Step 2: Injection volume 2.5 mg ÷ 5 mg/mL = 0.5 mL = 50 units

Result: Draw to the 50-unit mark for each 2.5 mg dose.

Ipamorelin Example

Given:

• Vial contains: 5 mg Ipamorelin
• Water added: 2.5 mL bacteriostatic water
• Target dose: 200 mcg three times daily

Calculation:

Step 1: Concentration 5,000 mcg ÷ 2.5 mL = 2,000 mcg/mL

Step 2: Injection volume 200 mcg ÷ 2,000 mcg/mL = 0.1 mL = 10 units

Result: Draw to the 10-unit mark for each 200 mcg dose.

CJC-1295 (no DAC) Example

Given:

• Vial contains: 2 mg CJC-1295
• Water added: 2 mL bacteriostatic water
• Target dose: 100 mcg twice daily

Calculation:

Step 1: Concentration 2,000 mcg ÷ 2 mL = 1,000 mcg/mL

Step 2: Injection volume 100 mcg ÷ 1,000 mcg/mL = 0.1 mL = 10 units

Result: Draw to the 10-unit mark for each 100 mcg dose.

Semaglutide Example

Given:

• Vial contains: 5 mg semaglutide
• Water added: 2 mL bacteriostatic water
• Target dose: 0.25 mg weekly (starting dose)

Calculation:

Step 1: Concentration 5 mg ÷ 2 mL = 2.5 mg/mL

Step 2: Injection volume 0.25 mg ÷ 2.5 mg/mL = 0.1 mL = 10 units

Result: Draw to the 10-unit mark for 0.25 mg dose.

Choosing Your Reconstitution Volume

The amount of water you add affects injection volume—not dose effectiveness. More water = larger injection volume per dose. Less water = smaller injection volume per dose.

Considerations

Practical Guidelines

For peptides dosed in mcg (BPC-157, Ipamorelin, etc.):

• 2-2.5 mL water for 5 mg vials gives convenient concentrations
• Results in 2,000-2,500 mcg/mL
• Most doses fall between 5-20 units

For peptides dosed in mg (TB-500, semaglutide):

• 1-2 mL water keeps volumes manageable
• Results in 2.5-5 mg/mL
• Most doses still under 50 units

Quick Reference Tables

BPC-157 (5 mg vial + 2 mL BAC water = 2,500 mcg/mL)

TB-500 (5 mg vial + 1 mL BAC water = 5 mg/mL)

Ipamorelin (5 mg vial + 2.5 mL BAC water = 2,000 mcg/mL)

Semaglutide (5 mg vial + 2 mL BAC water = 2.5 mg/mL)

Body Weight-Based Dosing

Some protocols adjust doses based on body weight. Here's how to calculate:

Formula

Total dose = Body weight (kg) × Dose per kg

Example: BPC-157 at 10 mcg/kg

Person weighs 80 kg (176 lbs):

• Dose = 80 kg × 10 mcg/kg = 800 mcg

Using concentration of 2,500 mcg/mL:

• Volume = 800 mcg ÷ 2,500 mcg/mL = 0.32 mL = 32 units

Weight Conversion

Formula: kg = lbs ÷ 2.205

Common Dosing Mistakes

Mistake 1: Confusing mg and mcg

1 mg = 1,000 mcg

A 250 mcg dose is very different from 250 mg. Always double-check your units.

Mistake 2: Forgetting concentration depends on water added

Adding more water doesn't change the total peptide—it changes concentration. 5 mg is 5 mg whether dissolved in 1 mL or 5 mL.

Mistake 3: Not accounting for peptide content

Some vials contain 5 mg total powder but only 80% peptide content (the rest is counterions/moisture). For most purposes, use the labeled amount. For precise calculations, account for peptide content if specified on COA.

Mistake 4: Using the wrong syringe scale

Verify your syringe markings. Most insulin syringes are U-100 (100 units = 1 mL), but U-40 and U-50 syringes exist.

Mistake 5: Rounding errors

For small doses, precision matters. Use a syringe with appropriate graduations (0.5 mL/50 unit syringes for very small doses).

Building Your Own Calculator

Simple Spreadsheet Method

Create a spreadsheet with:

• Cell A1: Peptide amount (mg)
• Cell A2: Water added (mL)
• Cell A3: Target dose (mcg)
• Cell A4: Formula: =(A1*1000)/A2 (gives concentration in mcg/mL)
• Cell A5: Formula: =A3/A4 (gives volume in mL)
• Cell A6: Formula: =A5*100 (gives syringe units)

Double-Check Method

Always verify calculations using the reverse:

• If you're injecting 10 units (0.1 mL) of a 2,500 mcg/mL solution
• You're getting: 0.1 mL × 2,500 mcg/mL = 250 mcg ✓

Practical Tips

Label Everything

After reconstitution, label vials with:

• Reconstitution date
• Concentration (e.g., "2,500 mcg/mL")
• Expiration (typically 4-6 weeks after mixing)

Use the Same Reconstitution Volume Consistently

Picking a standard volume (e.g., always 2 mL for 5 mg vials) reduces calculation errors and makes dosing intuitive.

Round Appropriately

For most peptides, precision to the nearest 0.5-1 unit is sufficient. Don't stress about hitting exactly 7.3 units—7 or 7.5 is fine.

Keep a Dosing Log

Track each injection with date, time, dose, and any notes. This helps identify patterns and troubleshoot issues.

Frequently Asked Questions

Does it matter what concentration I use? No—the total peptide you receive depends on your calculated dose, not concentration. Concentration affects injection volume, not effectiveness.

What if my dose doesn't work out to an even number? Round to the nearest practical measurement. Slight variations (±5-10%) are acceptable for most protocols.

Can I use a different amount of water than recommended? Yes. The "recommended" amount is for convenience. More water makes small doses easier to measure; less water means smaller injection volumes.

What if I added the wrong amount of water? Calculate your actual concentration and adjust injection volume accordingly. The peptide is still usable.

How accurate are insulin syringes? Standard U-100 syringes are accurate to approximately ±5% at larger volumes. For very small doses (<5 units), use a smaller syringe (0.3 mL/30 unit) for better precision.

Summary

Accurate peptide dosing requires:

1. Know your concentration: Peptide amount ÷ Water added
2. Calculate injection volume: Target dose ÷ Concentration
3. Convert to syringe units: Volume (mL) × 100 = Units

Master these calculations and you can confidently dose any peptide at any concentration. When in doubt, double-check your math using the reverse calculation to verify your result.