All peptides referenced on this page are sold and discussed strictly for in vitro research and laboratory use. They are not approved for human consumption, therapeutic use, or veterinary application. Information on this page is provided for educational and reference purposes only.
Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide powder into a liquid solvent to produce a stable, dosable solution. The procedure itself takes under five minutes, but the math behind it — how much bacteriostatic water to add, what concentration that produces, and how many units on an insulin syringe correspond to a target dose — is where most errors occur.
This reference combines an interactive calculator, a master ratio table covering 25+ commonly used research peptides, the standard reconstitution procedure, BAC water selection guidance, and post-reconstitution stability data into a single document. It is written to serve as a working reference at the bench, not a tutorial.
Reconstitution Calculator
Enter the amount of peptide in your vial, the volume of bacteriostatic water you will add, and your target dose. The calculator outputs concentration, volume per dose, and the corresponding mark on a standard U-100 insulin syringe.
Inputs
Results
Master Reconstitution Table
Reference reconstitution ratios for commonly used research peptides. The values below produce the standard concentrations used in published protocols. Other ratios are valid — recalculate using the calculator above if you deviate.
| Peptide | Vial Size | BAC Water | Concentration | Common Dose | Units (U-100) |
|---|---|---|---|---|---|
| BPC-157 | 5 mg | 2 mL | 2,500 mcg/mL | 250 mcg | 10 |
| BPC-157 | 10 mg | 4 mL | 2,500 mcg/mL | 250 mcg | 10 |
| TB-500 | 5 mg | 2.5 mL | 2,000 mcg/mL | 2 mg | 100 |
| TB-500 | 10 mg | 5 mL | 2,000 mcg/mL | 2 mg | 100 |
| GHK-Cu | 50 mg | 2 mL | 25 mg/mL | 1–2 mg | 4–8 |
| GHK-Cu | 100 mg | 4 mL | 25 mg/mL | 1–2 mg | 4–8 |
| CJC-1295 (no DAC) | 2 mg | 2 mL | 1,000 mcg/mL | 100 mcg | 10 |
| CJC-1295 (with DAC) | 2 mg | 2 mL | 1,000 mcg/mL | 1–2 mg/week | 100–200 |
| Ipamorelin | 5 mg | 2.5 mL | 2,000 mcg/mL | 200 mcg | 10 |
| Sermorelin | 5 mg | 2.5 mL | 2,000 mcg/mL | 200 mcg | 10 |
| Tesamorelin | 10 mg | 2 mL | 5 mg/mL | 1 mg | 20 |
| Semaglutide | 5 mg | 2 mL | 2,500 mcg/mL | 250 mcg/week | 10 |
| Tirzepatide | 10 mg | 2 mL | 5 mg/mL | 2.5 mg/week | 50 |
| Retatrutide | 10 mg | 2 mL | 5 mg/mL | 2–4 mg/week | 40–80 |
| AOD-9604 | 2 mg | 2 mL | 1,000 mcg/mL | 300 mcg | 30 |
| HGH Fragment 176-191 | 5 mg | 2.5 mL | 2,000 mcg/mL | 500 mcg | 25 |
| MOTS-c | 10 mg | 2 mL | 5 mg/mL | 5 mg/week | 100 |
| Epitalon | 10 mg | 2 mL | 5 mg/mL | 5–10 mg | 100–200 |
| SS-31 | 5 mg | 2 mL | 2.5 mg/mL | 1–5 mg | 40–200 |
| Semax | 30 mg | 3 mL | 10 mg/mL | 300 mcg–1 mg | 3–10 |
| Selank | 10 mg | 1 mL | 10 mg/mL | 250 mcg–1 mg | 2.5–10 |
| Thymosin Alpha-1 | 5 mg | 2 mL | 2.5 mg/mL | 1.6 mg | 64 |
| PT-141 | 10 mg | 1 mL | 10 mg/mL | 1–2 mg | 10–20 |
| Melanotan II | 10 mg | 2 mL | 5 mg/mL | 250–500 mcg | 5–10 |
| IGF-1 LR3 | 1 mg | 1 mL | 1 mg/mL | 20–50 mcg | 2–5 |
| DSIP | 5 mg | 2 mL | 2.5 mg/mL | 100–500 mcg | 4–20 |
| Hexarelin | 5 mg | 2.5 mL | 2,000 mcg/mL | 100 mcg | 5 |
| KPV | 10 mg | 2 mL | 5 mg/mL | 500 mcg | 10 |
| LL-37 | 5 mg | 2 mL | 2.5 mg/mL | 100–500 mcg | 4–20 |
| Pentadeca Arginate | 10 mg | 4 mL | 2,500 mcg/mL | 250–500 mcg | 10–20 |
"Common dose" values reflect ranges reported in published research literature for each compound. They are reference figures, not protocols for human use.
Step-by-Step Reconstitution Procedure
The standard procedure for reconstituting a lyophilized peptide. Total time: approximately 5 minutes plus 10–20 minutes of room-temperature equilibration.
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Bring the peptide vial to room temperature
Remove the lyophilized peptide vial from cold storage. Allow it to sit on the bench for 10 to 20 minutes until it reaches room temperature. Adding cold solvent to a cold vial slows dissolution and can cause condensation inside the vial.
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Sanitize both vial stoppers
Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with a fresh alcohol pad. Allow the alcohol to air-dry — do not blot.
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Draw the calculated volume of bacteriostatic water
Using a sterile syringe (typically a 3 mL syringe with a 21-gauge drawing needle), draw the precise volume of bacteriostatic water determined by the calculator or master table.
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Inject water slowly against the vial wall
Insert the needle into the peptide vial at a steep angle so that water flows down the inner glass wall rather than directly onto the lyophilized powder. Inject slowly over 10 to 20 seconds. This minimizes foaming and protects peptide structure.
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Swirl gently to dissolve
Hold the vial upright and swirl in slow circles until the powder fully dissolves and the solution appears clear. Do not shake. Most peptides dissolve within 30 to 90 seconds of swirling. If powder remains, set the vial aside for 5 to 10 minutes at room temperature and swirl again.
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Inspect the solution
The reconstituted solution should be clear and colorless. GHK-Cu and copper-containing peptides will appear pale blue — this is normal. If you see particulate matter, persistent cloudiness, or an unexpected color, do not use the vial.
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Refrigerate
Store the reconstituted vial between 2 and 8 °C, protected from light. Label the vial with the reconstitution date. Use within the stability window for that specific peptide (see storage section).
BAC Water Selection
Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative. The benzyl alcohol prevents bacterial growth in the vial across repeated needle entries, which is what allows a reconstituted peptide vial to be drawn from over multiple days or weeks without contamination.
Standard solvent comparison
| Solvent | Composition | Use Case | Stability |
|---|---|---|---|
| Bacteriostatic water | Sterile water + 0.9% benzyl alcohol | Multi-dose vials — the standard for research peptides | Extends reconstituted peptide stability significantly |
| Sterile water for injection | Sterile water, no preservative | Single-use only, within 24 hours | No preservative protection |
| 0.9% saline (NS) | Sterile water + 0.9% NaCl | Specific peptides with poor solubility in BAC water | No preservative protection |
| Acetic acid (0.6%) | Sterile water + dilute acetic acid | Highly hydrophobic peptides (rare) | Lower pH may affect stability |
Storage After Reconstitution
Once reconstituted, peptide stability is governed by three factors: temperature, light exposure, and time. The general rules:
- Refrigerated (2–8 °C): stable for the peptide-specific window listed below
- Frozen (−20 °C or colder): stable for 3–6 months, but freeze in single-use aliquots — repeated freeze/thaw cycles degrade most peptides
- Room temperature: not recommended after reconstitution; use within 24 hours if unavoidable
- Light: store in original carton or wrap in foil; UV exposure degrades aromatic amino acids (Trp, Tyr, Phe)
Refrigerated stability by peptide
| Peptide | Stability (Refrigerated) | Freezable? |
|---|---|---|
| BPC-157 | Up to 30 days | Yes — recommended for >30 day storage |
| TB-500 | Up to 30 days | Yes |
| GHK-Cu | Up to 60 days (very stable) | Yes |
| CJC-1295 (no DAC) | 7–14 days | Yes — recommended |
| CJC-1295 (with DAC) | Up to 30 days | Yes |
| Ipamorelin | 14–21 days | Yes |
| Sermorelin | 7–14 days | Yes — recommended |
| Tesamorelin | 14 days | Yes |
| Semaglutide | Up to 56 days | Yes |
| Tirzepatide | Up to 28 days | Yes |
| MOTS-c | 14–21 days | Yes |
| Epitalon | 14–21 days | Yes |
| Semax / Selank | Up to 30 days | Yes |
| Thymosin Alpha-1 | 14 days | Yes — recommended |
| PT-141 | Up to 30 days | Yes |
| AOD-9604 | 14 days | Yes |
| IGF-1 LR3 | 14–21 days | Yes — recommended |
Insulin Syringe Unit Chart
Research peptides are typically drawn using U-100 insulin syringes. On a U-100 syringe, the scale is calibrated so that 100 units = 1 mL. This means 1 unit = 0.01 mL.
Volume-to-unit conversion
| Volume (mL) | Units (U-100) | Volume (mL) | Units (U-100) |
|---|---|---|---|
| 0.05 | 5 | 0.50 | 50 |
| 0.10 | 10 | 0.60 | 60 |
| 0.15 | 15 | 0.70 | 70 |
| 0.20 | 20 | 0.80 | 80 |
| 0.25 | 25 | 0.90 | 90 |
| 0.30 | 30 | 1.00 | 100 |
| 0.40 | 40 | — | — |
Reconstitution Math
The full set of formulas for any reconstitution scenario. All derive from a single relationship: concentration = mass ÷ volume.
Core formulas
| To find | Formula | Example |
|---|---|---|
| Concentration (mg/mL) | peptide mg ÷ BAC water mL | 5 mg ÷ 2 mL = 2.5 mg/mL |
| Concentration (mcg/mL) | (peptide mg ÷ BAC water mL) × 1000 | 2.5 mg/mL × 1000 = 2,500 mcg/mL |
| Volume per dose (mL) | dose mcg ÷ concentration mcg/mL | 250 ÷ 2,500 = 0.10 mL |
| Units on U-100 syringe | volume mL × 100 | 0.10 × 100 = 10 units |
| Mcg per unit | concentration mcg/mL ÷ 100 | 2,500 ÷ 100 = 25 mcg/unit |
| Total doses per vial | (peptide mg × 1000) ÷ dose mcg | (5 × 1000) ÷ 250 = 20 doses |
Unit conversions
- 1 mg = 1,000 mcg
- 1 mcg = 0.001 mg
- 1 mL = 100 units (on a U-100 insulin syringe)
- 1 unit = 0.01 mL
Common Reconstitution Mistakes
1. Shaking the vial
Shaking generates shear forces that can disrupt peptide bonds and create foam that's hard to draw cleanly. Swirl gently — never shake.
2. Injecting water directly onto the powder
Aiming the syringe at the lyophilized cake causes foaming and uneven dissolution. Always inject water down the inside wall of the vial.
3. Using cold solvent on a cold vial
Skipping the room-temperature equilibration step slows dissolution and risks condensation that complicates the math. 10–20 minutes at room temperature first.
4. Confusing mg with mcg in dose calculations
A 1,000-fold error. Always verify whether your target dose is in milligrams or micrograms before drawing.
5. Reusing the same syringe across vials
Introduces cross-contamination between compounds and bacterial risk. Fresh sterile syringe and needle for every draw.
6. Not labeling the reconstitution date
You will not remember when you reconstituted a vial three weeks from now. Label every vial immediately after reconstitution.
7. Leaving vials at room temperature
Reconstituted peptides degrade rapidly above 8 °C. Return to refrigeration immediately after each use.
Frequently Asked Questions
What is bacteriostatic water and why is it used for peptide reconstitution?
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, which is why bacteriostatic water is the standard solvent for reconstituting multi-dose peptide vials. A vial reconstituted with bacteriostatic water remains stable significantly longer than one reconstituted with plain sterile water.
How long does a reconstituted peptide last in the refrigerator?
Stability depends on the peptide. Most reconstituted peptides remain stable for 14 to 30 days when stored between 2 and 8 °C. Smaller, more stable peptides like BPC-157 and TB-500 can last up to 30 days. Larger or more fragile peptides like CJC-1295 without DAC may only retain potency for 7 to 14 days. For multi-month storage, freeze in single-use aliquots. See the storage section for per-peptide stability values.
How do I read insulin syringe units for peptide dosing?
Standard U-100 insulin syringes are calibrated so that 100 units equals 1 mL. Therefore 1 unit equals 0.01 mL. To convert micrograms to units, divide your dose in micrograms by the concentration of your reconstituted peptide in micrograms per unit. The reconstitution calculator above outputs units directly.
Can I shake the vial to dissolve the peptide faster?
No. Shaking can denature peptide bonds and damage the molecular structure, reducing potency. Always swirl gently in a circular motion. If the peptide does not fully dissolve after several minutes of swirling, set the vial aside at room temperature for 10 to 15 minutes and swirl again.
What happens if I use the wrong amount of bacteriostatic water?
Using a different volume changes the concentration but does not damage the peptide. Less water creates a more concentrated solution requiring fewer units per dose; more water creates a more dilute solution requiring more units. Recalculate using the formulas above or the calculator. The total peptide amount in the vial is unchanged.
Why does my peptide vial appear foamy after reconstitution?
Foaming results from injecting bacteriostatic water too quickly or directly onto the powder. Foam is not necessarily damaging but suggests excessive agitation. Allow the vial to settle for 10 to 15 minutes before drawing a dose. Going forward, inject bacteriostatic water slowly down the inner wall of the vial.
Can I reconstitute with sterile water instead of bacteriostatic water?
Sterile water can be used for single-dose reconstitution that will be used within 24 hours. For any multi-dose vial that will be drawn from repeatedly over days or weeks, bacteriostatic water is required to prevent bacterial contamination of the vial.
Do I need to filter the peptide after reconstitution?
No. Research-grade peptides supplied as lyophilized powder are produced under sterile conditions and do not require filtration after reconstitution if proper aseptic technique is used. Always use a fresh sterile needle for each draw.
Can I mix two peptides in the same vial?
Some peptides are co-administered (e.g. CJC-1295 + Ipamorelin) and can be mixed in the same syringe at the moment of drawing — but they are typically reconstituted in separate vials and combined immediately before use. Pre-mixing in a shared vial creates unpredictable stability profiles and is not recommended.
What size syringe should I use?
For most research peptide doses, a 0.5 mL (50 unit) U-100 insulin syringe with a 29- or 31-gauge needle provides the best balance of capacity and precision. For larger volume doses (50+ units), a 1 mL (100 unit) syringe is appropriate. For drawing bacteriostatic water during reconstitution, a 3 mL syringe with a 21-gauge drawing needle is standard.
All peptides referenced on this page are sold and discussed strictly for in vitro research and laboratory use. They are not approved by the FDA for human consumption, therapeutic use, or veterinary application. Information on this page is provided for educational and reference purposes only and does not constitute medical advice.
Reconstitution ratios in the master table reflect commonly used concentrations in published research literature. Concentrations marked as "common dose" are reference figures derived from research protocols and are not dosing recommendations for any human or animal subject.