Peptide Reconstitution Calculator
Free peptide reconstitution calculator. Enter vial size and water volume to calculate concentration per unit. Arithmetic tool only, not dosing advice.
Reconstituting a lyophilized peptide vial is arithmetic, not guesswork. The calculator below takes two inputs: the peptide amount in milligrams and the volume of bacteriostatic water added. It returns the concentration per milliliter and per 0.1ml tick mark on a standard insulin syringe. We built this tool because concentration errors are the most common mistake in peptide preparation, and they are entirely preventable with basic math.
The Reconstitution Formula
How the Math Works
The formula converts milligrams to micrograms, divides by total liquid volume and multiplies by draw volume. Written out:
Concentration (mcg per 0.1ml) = (peptide mg x 1000) / (water ml) x 0.1
That is it. Three operations. Multiply the vial amount by 1000 to convert milligrams to micrograms. Divide by the total water volume to get micrograms per milliliter. Then multiply by 0.1 to get the amount in each tick mark of a 1ml syringe. The calculator automates this, but knowing the formula lets you double-check the result by hand.
Example Calculations Table
The table below shows pre-calculated concentrations for the most commonly used vial and water combinations. All values assume complete dissolution of the peptide with no loss during the reconstitution process. We include both 5mg and 10mg vials because those are the sizes most frequently listed by vendors in our database.
| Vial (mg) | Water (ml) | mcg per ml | mcg per 0.1ml | Draws per vial (at 0.1ml) |
|---|---|---|---|---|
| 5 | 1 | 5,000 | 500 | 10 |
| 5 | 2 | 2,500 | 250 | 20 |
| 5 | 2.5 | 2,000 | 200 | 25 |
| 5 | 5 | 1,000 | 100 | 50 |
| 10 | 1 | 10,000 | 1,000 | 10 |
| 10 | 2 | 5,000 | 500 | 20 |
| 10 | 2.5 | 4,000 | 400 | 25 |
| 10 | 5 | 2,000 | 200 | 50 |
Notice how doubling the water volume halves the concentration. A 10mg vial with 2ml of water produces the same concentration per 0.1ml as a 5mg vial with 1ml of water: 500 mcg per tick. The total peptide amount stays the same. Only the concentration per unit of liquid changes.
Worked Example: Real Peptides BPC-157 10mg
Real Peptides sells a 10mg BPC-157 vial at $43.20. We know the vial size because it is listed on the product page. Adding 2ml of bacteriostatic water gives 5,000 mcg per ml. Each 0.1ml draw from a 1ml insulin syringe contains 500 mcg. The vial provides 20 draws at that volume.
Adding less water increases the concentration per draw. With 1ml of water, each 0.1ml tick delivers 1,000 mcg. With 2.5ml, each tick delivers 400 mcg. The choice depends on the concentration needed for a given research protocol. Our calculator above handles any combination.
When the Vial Size Is Unknown
PeptideGod's BPC-157 at $34.95 does not list a milligram amount on the product page. Without that number, the calculator cannot produce a result. This is not a limitation of the tool. It is a limitation of the product labeling. We mention this because buyers sometimes assume all BPC-157 vials contain the same amount. They may not. If you cannot confirm the peptide mass in the vial, the concentration calculation is unreliable. For vendor comparison details, visit our buying guide.
Step-by-Step Reconstitution Procedure
- Gather materials Lyophilized peptide vial, bacteriostatic water (USP-grade, 0.9% benzyl alcohol), alcohol swabs, insulin syringe (1ml with 0.1ml graduations)
- Swab both stoppers Clean the rubber stopper on both the peptide vial and the bacteriostatic water vial with alcohol. Allow 10 seconds to dry
- Draw water into syringe Pull the calculated volume of bacteriostatic water. Remove air bubbles by tapping the syringe barrel
- Add water to peptide vial Insert the needle at an angle and release water slowly down the inside wall of the vial. Do not spray directly onto the powder cake
- Dissolve gently Tilt and rotate the vial until the powder dissolves completely. Do not shake. Clear solution with no visible particles indicates full dissolution. This typically takes 1 to 3 minutes
- Label and store Write the date, peptide name and calculated concentration on the vial. Refrigerate at 2-8C (36-46F)
FAQ - Peptide Reconstitution
How much water should I add to a peptide vial?
That depends on the concentration you need. More water produces a lower concentration per draw. Less water produces a higher concentration. The calculator above accepts any combination of peptide amount and water volume. For a 10mg vial, common water volumes range from 1ml to 5ml. Each choice produces a different concentration, as shown in the reference table.
Does the type of water matter?
Yes. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits microbial growth. This allows multiple draws from the same vial over days or weeks. Sterile water has no preservative and should be used only if the entire vial will be consumed in a single session. Real Peptides sells USP-grade bacteriostatic water at $4.80 per 10ml vial. For more on peptide preparation, see our safety guide.
How long does reconstituted peptide last?
Most research protocols and vendor guidelines suggest using reconstituted peptide within 3 to 4 weeks when stored at 2-8C. The benzyl alcohol in bacteriostatic water slows microbial growth but does not stop it indefinitely. If the solution becomes cloudy, contains particles or changes color, discard it. Temperature stability degrades faster above 8C.
Can I use this calculator for any peptide?
The math applies to any lyophilized peptide vial where you know the milligram content. BPC-157, TB-500, MOTS-C, Epithalon. The formula is the same regardless of the peptide. The only requirement is knowing how many milligrams are in the vial. If the vendor does not disclose the amount, the calculation cannot be performed accurately.
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