How to Calculate Peptide Doses: Complete Dosing Guide for Beginners

One of the most intimidating aspects of peptide research is calculating doses after reconstitution. The math can seem overwhelming at first—you're working with micrograms, milligrams, milliliters, and international units all at once. But once you understand the simple formula, dosing becomes second nature.

This guide breaks down peptide dose calculations into clear, repeatable steps. Whether you're working with growth hormone secretagogues, healing peptides, or research compounds, the same principles apply.

ℹ️ Info: This guide is for educational and research purposes only. Always consult qualified professionals before handling any research compounds.

Understanding the Basics: Key Terms

Before diving into calculations, let's clarify the terminology:

Lyophilized powder: The freeze-dried peptide in your vial before reconstitution
Reconstitution: Adding bacteriostatic water (or sterile water) to dissolve the powder
Concentration: How much peptide is dissolved per milliliter of solution
mcg (micrograms): One millionth of a gram (1000 mcg = 1 mg)
mg (milligrams): One thousandth of a gram
mL (milliliters): Volume measurement (same as "cc" on some syringes)
IU (International Units): Standardized measurement for some peptides (like HGH)

🔑 Key Takeaways

1 mg = 1000 mcg (micrograms)
1 mL = 100 units on an insulin syringe
Concentration = Total peptide ÷ Total water added

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The Universal Dosing Formula

Every peptide dose calculation follows this simple formula:

The Formula

Volume to inject (mL) = Desired dose (mcg) ÷ Concentration (mcg/mL)

That's it. Once you know your concentration (determined during reconstitution), you just divide your desired dose by that number to get the volume you need to draw up.

Step 1: Determine Your Concentration

Your concentration depends on two things:

How much peptide is in the vial (usually labeled in mg)
How much water you add (your choice)

The formula is:

Concentration (mcg/mL) = Peptide amount (mcg) ÷ Water added (mL)

Example: BPC-157 (5mg vial)

You have a 5mg vial of BPC-157 and add 2mL of bacteriostatic water:

5mg = 5000 mcg
5000 mcg ÷ 2 mL = 2500 mcg/mL

Your concentration is 2500 mcg per mL.

Example: Ipamorelin (2mg vial)

You have a 2mg vial and add 2mL of water:

2mg = 2000 mcg
2000 mcg ÷ 2 mL = 1000 mcg/mL

Your concentration is 1000 mcg per mL.

✓ Pro Tip: Many researchers add 2mL to any vial for easy math. Others prefer adding water that creates a round concentration number (e.g., adding 2.5mL to a 5mg vial gives exactly 2000 mcg/mL).

Step 2: Calculate Your Injection Volume

Now apply the main formula. Let's use the BPC-157 example above (concentration: 2500 mcg/mL).

Example: 250mcg dose of BPC-157

Volume = 250 mcg ÷ 2500 mcg/mL = 0.1 mL

On an insulin syringe, 0.1 mL = 10 units.

Example: 300mcg dose of Ipamorelin

Using the Ipamorelin example (concentration: 1000 mcg/mL):

Volume = 300 mcg ÷ 1000 mcg/mL = 0.3 mL

On an insulin syringe, 0.3 mL = 30 units.

Reading Insulin Syringes

Most peptide researchers use insulin syringes, typically U-100 (100 units per mL). Understanding how to read them is crucial:

Syringe Reading (units)	Volume (mL)	Equivalent
10 units	0.10 mL	1/10 of a mL
25 units	0.25 mL	1/4 of a mL
50 units	0.50 mL	1/2 of a mL
100 units	1.00 mL	Full mL

⚠️ Warning: Always double-check your syringe type. U-100 syringes (most common) have 100 units per mL. U-40 syringes exist for veterinary use and will give incorrect doses if used with the standard formula.

Common Peptide Dosing Examples

Here are worked examples for popular research peptides using standard reconstitution volumes:

BPC-157

BPC-157 (5mg vial + 2mL water)

Concentration: 2500 mcg/mL

Desired Dose	Calculation	Syringe Units
250 mcg	250 ÷ 2500 = 0.10 mL	10 units
500 mcg	500 ÷ 2500 = 0.20 mL	20 units
750 mcg	750 ÷ 2500 = 0.30 mL	30 units

TB-500

TB-500 (5mg vial + 2.5mL water)

Concentration: 2000 mcg/mL

Desired Dose	Calculation	Syringe Units
2mg (2000 mcg)	2000 ÷ 2000 = 1.00 mL	100 units
2.5mg (2500 mcg)	2500 ÷ 2000 = 1.25 mL	125 units*
5mg (5000 mcg)	5000 ÷ 2000 = 2.50 mL	Two injections

*Requires a 1mL syringe or two separate draws

CJC-1295/Ipamorelin

Ipamorelin (5mg vial + 2.5mL water)

Concentration: 2000 mcg/mL

Desired Dose	Calculation	Syringe Units
100 mcg	100 ÷ 2000 = 0.05 mL	5 units
200 mcg	200 ÷ 2000 = 0.10 mL	10 units
300 mcg	300 ÷ 2000 = 0.15 mL	15 units

CJC-1295 (2mg vial + 2mL water)

Concentration: 1000 mcg/mL

Desired Dose	Calculation	Syringe Units
100 mcg	100 ÷ 1000 = 0.10 mL	10 units
150 mcg	150 ÷ 1000 = 0.15 mL	15 units
200 mcg	200 ÷ 1000 = 0.20 mL	20 units

Quick Reference Concentration Chart

Use this chart to quickly determine your concentration based on vial size and water added:

Vial Size	1mL Water	2mL Water	2.5mL Water
2mg	2000 mcg/mL	1000 mcg/mL	800 mcg/mL
5mg	5000 mcg/mL	2500 mcg/mL	2000 mcg/mL
10mg	10000 mcg/mL	5000 mcg/mL	4000 mcg/mL

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Choosing Your Reconstitution Volume

There's no single "correct" amount of water to add. Consider these factors:

💧

Less Water (1mL)

Higher concentration means smaller injection volumes. Good for frequent dosing or combining peptides.

💧💧

More Water (2-3mL)

Lower concentration makes measuring easier and reduces measurement errors. Better for beginners.

🧮

Round Numbers

Choose water volume that creates easy math: 2mL in a 2mg vial = exactly 1000 mcg/mL.

Avoiding Common Dosing Mistakes

Even experienced researchers make these errors:

Confusing mg and mcg

A 250mcg dose is NOT the same as 250mg. That's a 1000x difference. Always double-check units.

Forgetting to Convert

If your vial says "5mg" but you want to dose in mcg, convert first: 5mg = 5000mcg.

Not Recording Reconstitution

Write down how much water you added to each vial. Store this with the vial or in a log.

Using Wrong Syringe

U-100 syringes are standard. U-40 syringes (marked for veterinary insulin) will give 2.5x the intended dose.

📝 Note: When in doubt, recalculate. A few extra seconds of math is worth avoiding dosing errors.

International Units (IU) for HGH and HCG

Some peptides, particularly HGH and HCG, are measured in International Units rather than micrograms. The conversion varies by compound:

HGH (Human Growth Hormone)

Standard conversion: 1mg HGH ≈ 3 IU (varies slightly by manufacturer)

A 10IU vial of HGH reconstituted with 1mL of water:

Concentration = 10 IU/mL
For 2 IU dose: 2 ÷ 10 = 0.2 mL = 20 units on syringe
For 4 IU dose: 4 ÷ 10 = 0.4 mL = 40 units on syringe

HCG (Human Chorionic Gonadotropin)

A 5000 IU vial reconstituted with 2mL:

Concentration = 2500 IU/mL
For 250 IU dose: 250 ÷ 2500 = 0.1 mL = 10 units
For 500 IU dose: 500 ÷ 2500 = 0.2 mL = 20 units

Creating a Dosing Log

Keep track of every reconstitution and dose. A simple log might include:

Date of reconstitution
Peptide name and vial size
Amount of water added
Resulting concentration
Expiration date (typically 4-6 weeks for reconstituted peptides)
Daily doses administered

Sample Log Entry

BPC-157 | 5mg vial | 2mL BAC water | 2500 mcg/mL
Reconstituted: Feb 5, 2026 | Expires: March 5, 2026
Doses: 250mcg (10 units) — AM and PM

Frequently Asked Questions

What if I added the wrong amount of water?

Your peptide isn't ruined—just recalculate your concentration. If you added 3mL instead of 2mL to a 5mg vial, your concentration is now 5000 ÷ 3 = 1667 mcg/mL. Adjust your injection volume accordingly.

Can I mix multiple peptides in one syringe?

Some peptides can be combined (like CJC-1295 and Ipamorelin). However, mixing requires understanding potential interactions. Research each combination thoroughly. Never mix peptides that require different storage temperatures or have known interactions.

My dose is less than 5 units—how do I measure it?

Very small doses (under 5 units) are difficult to measure accurately with standard syringes. Consider adding more water during reconstitution to create a lower concentration, or look for 0.3mL syringes with finer graduation marks.

Does the type of water affect dosing calculations?

No—the calculations are the same whether you use bacteriostatic water (BAC), sterile water, or sodium chloride solution. However, bacteriostatic water is preferred for peptides that will be used over multiple days due to its preservative properties.

How do I dose peptides sold in "units" instead of mg?

Some peptides (especially HGH) are sold in IU (International Units). Use the same formula but substitute IU for mcg: Volume = Desired IU ÷ Concentration (IU/mL). The math works identically.

What's the difference between a 0.5mL and 1mL insulin syringe?

Both typically have 100 units per mL, but 0.5mL syringes only go up to 50 units with finer graduation marks (often every 1 unit vs every 2 units). Use 0.5mL syringes for doses under 50 units for better accuracy.

Summary: The Complete Dosing Process

Convert to Micrograms

Take your vial size in mg and multiply by 1000 to get mcg.

Calculate Concentration

Divide total mcg by the mL of water you added.

Calculate Volume

Divide your desired dose (mcg) by the concentration (mcg/mL).

Convert to Syringe Units

Multiply mL by 100 to get units on a U-100 syringe.

Double-Check

Verify your math before drawing up the dose.

🔑 Final Key Points

The universal formula: Volume (mL) = Dose (mcg) ÷ Concentration (mcg/mL)
Always convert mg to mcg by multiplying by 1000
On U-100 syringes: 10 units = 0.1 mL
Keep a dosing log to track reconstitution dates and concentrations
When uncertain, add more water for easier measurement

Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Peptides are research chemicals not approved for human use. Always consult a qualified healthcare provider before starting any new supplement, medication, or treatment. Individual results may vary.

ℹ️ Info: This guide is for educational and research purposes only. Always consult qualified professionals before handling any research compounds.