Peptide Dosage Calculator

What is Peptide Reconstitution?

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder with bacteriostatic water to create an injectable solution. Peptides are shipped as dry powder in sealed vials because they are more stable in this form. Before use, they must be carefully mixed with a precise amount of sterile bacteriostatic water (water containing 0.9% benzyl alcohol as a preservative).

The amount of water you add determines the concentration of the solution, which in turn determines how much liquid you need to draw into a syringe for each dose. Getting this calculation right is critical for accurate dosing.

Dosage Formulas

The calculation involves three steps:

The number of doses per vial is calculated as:

Common Peptides Reference

Peptide	Typical Dose	Frequency	Common Vial Size
BPC-157	250 – 500 mcg/day	1–2x daily	5 mg
TB-500 (Thymosin Beta-4)	2 – 5 mg	2x per week (loading), 1x/week (maintenance)	5 mg
Semaglutide	0.25 – 2.4 mg/week	1x per week	5 mg
Ipamorelin	200 – 300 mcg	2–3x daily	5 mg
CJC-1295 (no DAC)	100 – 300 mcg	2–3x daily	2 mg or 5 mg
GHK-Cu	200 – 600 mcg	1x daily	50 mg
Tirzepatide	2.5 – 15 mg/week	1x per week	5 mg, 10 mg, 15 mg
Tesamorelin	2 mg	1x daily	2 mg

Syringe Reading Diagram

How to Reconstitute Peptides

1. Clean the vial tops: Wipe both the peptide vial and bacteriostatic water vial with alcohol swabs and let them dry for 30 seconds.
2. Draw the water: Using a fresh syringe, draw the desired amount of bacteriostatic water. Common amounts are 1 mL or 2 mL.
3. Inject slowly: Insert the needle into the peptide vial at an angle and let the water run slowly down the side of the glass. Never spray water directly onto the powder — this can damage the peptide.
4. Swirl gently: Once water is added, gently swirl the vial. Do not shake vigorously as this can denature the peptide and reduce potency.
5. Wait if needed: Some peptides dissolve immediately, while others may take 5–10 minutes. The solution should be clear with no visible particles.

Storage & Handling

• Before reconstitution: Store lyophilized peptides at room temperature or refrigerated (2–8°C) for short-term, or frozen (-20°C) for long-term storage.
• After reconstitution: Always refrigerate at 2–8°C (standard refrigerator). Never freeze reconstituted peptides.
• Shelf life: Most reconstituted peptides remain stable for 3–4 weeks when stored properly in the refrigerator. Bacteriostatic water helps preserve the solution longer than sterile water.
• Light protection: Keep vials away from direct sunlight. Some peptides are light-sensitive.
• Contamination: Always use a new needle when drawing from vials. Use alcohol swabs before each puncture. If the solution becomes cloudy or discolored, discard it.

Injection Technique

Subcutaneous Injection (Most Common)

Most peptides are administered subcutaneously (under the skin) using an insulin syringe with a 29–31 gauge needle (typically 0.5 inch length). Common injection sites include:

• Abdomen: The most common site. Inject into the fatty tissue around the navel, at least 2 inches away from the belly button. Rotate injection sites.
• Thigh: Outer front part of the upper thigh, rotating between left and right.
• Upper arm: Back of the upper arm (may require assistance).

Steps for Injection

1. Wash hands thoroughly with soap and water
2. Clean the injection site with an alcohol swab and let it air-dry
3. Draw the calculated dose into the syringe, remove air bubbles by tapping and pushing gently
4. Pinch the skin at the injection site to create a fold
5. Insert the needle at a 45–90 degree angle
6. Inject slowly and steadily
7. Remove the needle and apply gentle pressure if needed
8. Dispose of the syringe safely in a sharps container

Worked Example

You have a 5 mg vial of BPC-157 and want to take a 250 mcg dose. You add 2 mL of bacteriostatic water.

So you would draw to the 10 unit mark on an insulin syringe. The vial would provide 5000 mcg ÷ 250 mcg = 20 doses.

Frequently Asked Questions

What is bacteriostatic water?

Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol, which acts as a preservative by inhibiting bacterial growth. This allows multi-dose vials to remain sterile for up to 28 days. It is the preferred diluent for peptide reconstitution. Do not confuse it with sterile water (which has no preservative and must be used within 24 hours).

Does the amount of water I add affect potency?

No. The total amount of peptide in the vial remains the same regardless of how much water you add. Adding more water simply means each mL contains less peptide, so you need to draw more liquid per dose. Adding less water makes a more concentrated solution, requiring less volume per dose. It is purely a concentration change.

Can I use regular water or saline?

Never use tap water or distilled water for injection. Bacteriostatic water is strongly recommended for multi-dose use. Normal saline (0.9% NaCl) can be used but lacks preservative, so the vial should be used within 24 hours. Sterile water for injection can also be used but, like saline, should be used promptly.

What size syringe should I use?

For peptide injections, a standard 1 mL (100 unit) insulin syringe with a 29–31 gauge needle is most common. For very small doses, a 0.5 mL (50 unit) syringe provides finer graduation marks and greater precision. For larger volume doses, a 1 mL luer-lock syringe may be more appropriate.

How long do reconstituted peptides last?

When mixed with bacteriostatic water and stored in the refrigerator (2–8°C), most peptides remain stable for 3–4 weeks. Some more stable peptides like BPC-157 may last longer. Always inspect the solution before each use — discard if cloudy, discolored, or containing particles.