Tools

Peptide Reconstitution Calculator

Calculate reconstitution volumes, syringe draw amounts, and dosing for any peptide. Educational use only — always follow your prescriber's instructions.

Quick presets

Peptide in vial

Bacteriostatic water

Desired dose

mcg

Syringe size

1 mL (100 units)0.5 mL (50 units)0.3 mL (30 units)

Draw to this mark

units(0.10 mL)

Concentration

2,500

mcg/mL

Volume per dose

0.10

Doses per vial

doses

Days supply

@ 1x/day

Show the math›

5 mg ÷ 2 mL = 2.50 mg/mL = 2,500 mcg/mL

250 mcg ÷ 2,500 mcg/mL = 0.100 mL

0.100 mL × 100 units/1 mL = 10 units

How to Reconstitute Peptides

Flow diagram showing how the reconstitution calculator works — Reconstitution process overview — vial to measured dose

Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a liquid solution for administration. Proper technique ensures accurate dosing and maintains peptide stability.

Gather materials: peptide vial, bacteriostatic water (BAC water), alcohol swabs, and an insulin syringe (U-100).
Clean the vial stopper of both the peptide vial and BAC water bottle with an alcohol swab. Allow to air dry.
Draw bacteriostatic water into your syringe — the amount determined by your desired concentration (use the calculator above).
Inject water into the peptide vial. Insert the needle through the stopper at a slight angle. Slowly dispense the water against the glass wall of the vial — never spray directly onto the lyophilized powder.
Gently swirl the vial until the powder is fully dissolved. Do not shake — shaking can denature the peptide and reduce potency.
Refrigerate at 2–8°C (standard refrigerator temperature). Reconstituted peptides mixed with BAC water are typically stable for up to 28 days.

Understanding Syringe Units

Insulin syringes measure volume in “units” rather than milliliters, which causes confusion for many peptide users. Here is the conversion:

Syringe Size	Total Units	mL per Unit
1 mL	100 units	0.01 mL
0.5 mL	50 units	0.01 mL
0.3 mL	30 units	0.01 mL

Regardless of syringe size, 1 unit always equals 0.01 mL. The only difference is total capacity: a 0.3 mL syringe has finer graduation marks, making it easier to measure very small volumes precisely.

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Frequently Asked Questions

How much bacteriostatic water should I use?

The amount of BAC water depends on your desired concentration. Common volumes are 1–3 mL. More water means a more dilute solution (easier to measure small doses), while less water means a more concentrated solution (fewer injections per vial). Most protocols suggest 1–2 mL for a 5 mg vial.

Can I use sterile water instead of bacteriostatic water?

Sterile water can be used but lacks the preservative (benzyl alcohol) found in bacteriostatic water. Without it, the reconstituted solution should be used within 24 hours and cannot be stored for multi-dose use. Bacteriostatic water allows storage for up to 28 days when refrigerated.

How long does reconstituted peptide last?

When reconstituted with bacteriostatic water and stored at 2–8°C (refrigerator), most peptides remain stable for up to 28 days. Never freeze reconstituted peptides. Protect from light. If the solution becomes cloudy or discolored, discard it.

What if I added too much or too little water?

Adding more or less water doesn't change the total amount of peptide in the vial — it only changes the concentration. If you added more water than planned, each unit on your syringe will contain less peptide (you'll need to draw more). If you added less, each unit contains more (draw less). Use this calculator with your actual water volume to get the correct syringe draw.

How do I read an insulin syringe?

A standard U-100 insulin syringe holds 1 mL total, divided into 100 units. Each small mark equals 1 unit (0.01 mL). Larger marks appear every 10 units. A 0.5 mL syringe has 50 units, and a 0.3 mL syringe has 30 units. The spacing between marks is 0.01 mL regardless of syringe size.

What's the difference between mcg and mg?

1 milligram (mg) = 1,000 micrograms (mcg). This is the most common source of dosing errors. Always double-check whether your dose is in mg or mcg. For example, 250 mcg = 0.25 mg. Most peptide doses are measured in mcg, while vial sizes are labeled in mg.

Can I mix two peptides in the same syringe?

Some peptides can be combined in the same injection (e.g., CJC-1295 and Ipamorelin). However, you should never mix peptides in the same vial. Draw from each vial separately into the same syringe if combining. Always consult your provider before combining peptides.

Educational Use Only

This calculator is provided for educational and informational purposes. It is not medical advice. Always follow your healthcare provider's dosing instructions. The Peptide Effect does not sell, prescribe, or endorse any specific peptide product.

Last reviewed: February 2026