This protocol is intended for licensed researchers working with research-grade peptides in controlled laboratory settings. Research peptides are not FDA-approved for human use. This guide does not constitute medical advice.
Automatically calculate draw volumes, syringe units, and doses-per-vial for 27 research peptides based on your reconstitution volume and dose.
Step-by-Step Reconstitution Protocol
Follow these six steps in order. Sterile technique throughout is essential — contamination is the primary cause of degraded peptides and confounded research results.
Gather Your Supplies
Before beginning, assemble all required materials. Working with incomplete supplies mid-process increases contamination risk.
- Lyophilized (freeze-dried) peptide vial
- Bacteriostatic water (BAC water, 0.9% benzyl alcohol) — NOT sterile water for injection
- Insulin syringe (1 mL, 28–31 gauge) for reconstitution
- Alcohol swabs (70% isopropyl alcohol)
- Clean, flat surface or sterile field
Calculate Your Reconstitution Volume
The amount of BAC water you add determines the concentration of your solution. This affects how much you draw for each dose.
- Common convention: add 1 mL BAC water to a 5 mg vial → concentration = 5 mg/mL = 5,000 mcg/mL
- Alternative: add 2 mL BAC water to a 5 mg vial → concentration = 2.5 mg/mL = 2,500 mcg/mL
- For small doses (e.g., 250 mcg), higher dilution (2 mL) gives more precise draw volumes
- Use the calculator below to determine your exact draw volume
Prepare the Vials
Sterile technique is essential. Contamination is the primary cause of degraded peptides and adverse reactions in research.
- Wipe the rubber stopper of the peptide vial with an alcohol swab — allow to air dry for 10–15 seconds
- Wipe the rubber stopper of the BAC water vial with a fresh alcohol swab — allow to air dry
- Do not touch the rubber stoppers after wiping
- Do not recap the syringe needle after drawing — keep it sterile
Draw the BAC Water
Draw the calculated volume of BAC water into the insulin syringe.
- Insert the syringe needle through the center of the BAC water vial stopper
- Invert the BAC water vial and draw the required volume (e.g., 1 mL)
- Remove any air bubbles by gently tapping the syringe and pushing air out
- Confirm the correct volume is in the syringe before proceeding
Add BAC Water to the Peptide Vial
This is the most critical step. The goal is to dissolve the peptide without denaturing it.
- Insert the syringe needle through the rubber stopper of the peptide vial at an angle
- Direct the BAC water stream slowly down the SIDE of the vial — do not aim directly at the peptide powder
- Add the water slowly over 10–15 seconds
- Do NOT shake the vial — shaking can denature the peptide
- Gently swirl the vial in a circular motion until the powder is fully dissolved
- The solution should be clear and colorless (some peptides may have a slight tint)
Inspect and Store
Before storing, verify the solution quality and label the vial.
- Inspect the solution: it should be clear with no visible particles or cloudiness
- Discard if the solution is cloudy, has visible particles, or has an unusual color
- Label the vial with the peptide name, concentration, date reconstituted, and expiry date (28 days from reconstitution)
- Store reconstituted peptide at 2–8°C (refrigerator) — do NOT freeze
- Keep away from light
Concentration Reference Table
The following table shows the resulting concentration and draw volumes for common vial sizes and reconstitution volumes. Values are for a 100-unit (1 mL) insulin syringe.
| Vial Size | BAC Water | Concentration | 250 mcg dose | 500 mcg dose |
|---|---|---|---|---|
| 5 mg (5,000 mcg) | 1 mL | 5,000 mcg/mL | 0.05 mL (5 IU) | 0.10 mL (10 IU) |
| 5 mg (5,000 mcg) | 2 mL | 2,500 mcg/mL | 0.10 mL (10 IU) | 0.20 mL (20 IU) |
| 10 mg (10,000 mcg) | 1 mL | 10,000 mcg/mL | 0.025 mL (2.5 IU) | 0.05 mL (5 IU) |
| 10 mg (10,000 mcg) | 2 mL | 5,000 mcg/mL | 0.05 mL (5 IU) | 0.10 mL (10 IU) |
| 2 mg (2,000 mcg) | 1 mL | 2,000 mcg/mL | 0.125 mL (12.5 IU) | 0.25 mL (25 IU) |
IU = insulin units on a 100-unit syringe. 1 mL = 100 IU. Formula: Draw volume (mL) = Dose (mcg) ÷ Concentration (mcg/mL)
Storage Quick Reference
Lyophilized (Dry)
- Keep dry and away from light
- Avoid repeated temperature cycling
- Stable for long-term storage
Reconstituted (BAC Water)
- Do NOT freeze after reconstitution
- Keep away from light
- Discard if cloudy or particulate
Signs of Degradation
- Cloudy or turbid solution
- Visible particles or precipitate
- Unusual color or odor
Frequently Asked Questions
What is the best solvent for reconstituting peptides?
Bacteriostatic water (BAC water, 0.9% benzyl alcohol) is the standard solvent for reconstituting research peptides. The benzyl alcohol acts as a preservative, extending the shelf life of the reconstituted solution to 28–30 days when refrigerated. Sterile water for injection can be used if the solution will be used immediately, but it has no preservative and should not be stored for extended periods. Acetic acid (0.1–1%) is sometimes used for peptides that are poorly soluble in water (e.g., some GHRPs), but BAC water is the default choice.
How much BAC water should I add to reconstitute a peptide?
The amount of BAC water determines the concentration of your solution. A common standard is 1 mL per 5 mg vial (5,000 mcg/mL concentration) or 2 mL per 5 mg vial (2,500 mcg/mL). The choice depends on your target dose — smaller doses are easier to measure accurately at lower concentrations (more BAC water). Use the concentration formula: Concentration (mcg/mL) = Peptide amount (mcg) ÷ BAC water volume (mL). Then: Draw volume (mL) = Dose (mcg) ÷ Concentration (mcg/mL).
Can I use sterile water instead of BAC water?
Yes, but with limitations. Sterile water for injection is acceptable for immediate use, but it contains no preservative. Without benzyl alcohol, bacteria can grow in the solution, and the peptide may degrade more rapidly. If using sterile water, use the entire reconstituted vial within 24–48 hours and keep it refrigerated. For multi-dose vials used over several weeks, BAC water is strongly preferred.
How long does reconstituted peptide last?
Reconstituted peptides stored at 2–8°C (refrigerator) in BAC water typically remain stable for 28–30 days. Some peptides may be stable for longer; others may degrade faster. Signs of degradation include cloudiness, visible particles, or unusual color. Lyophilized (dry) peptide stored at −20°C can remain stable for 24+ months. Once reconstituted, do not freeze — freezing can damage the peptide structure.
Why should I not shake the peptide vial?
Vigorous shaking can denature peptides through mechanical agitation. The air-water interface created by shaking generates surface tension forces that can disrupt the peptide's three-dimensional structure. Always add BAC water slowly down the side of the vial and dissolve by gentle swirling. If the powder doesn't dissolve immediately, allow it to sit for 5–10 minutes and swirl again rather than shaking.
What does it mean if my reconstituted peptide is cloudy?
Cloudiness in a reconstituted peptide solution can indicate: (1) incomplete dissolution — allow more time and gentle swirling; (2) precipitation due to incorrect solvent or pH; (3) bacterial contamination; or (4) peptide degradation. A clear solution is the expected result for most peptides in BAC water. If the solution remains cloudy after adequate dissolution time, or if it was clear and became cloudy during storage, discard it and do not use it in research.
How do I calculate the draw volume for my dose?
Use this formula: Draw volume (mL) = Dose (mcg) ÷ Concentration (mcg/mL). Example: If you want a 250 mcg dose from a 5,000 mcg/mL solution: 250 ÷ 5,000 = 0.05 mL. On a 100-unit insulin syringe (1 mL = 100 IU), 0.05 mL = 5 IU. Always double-check your calculation before drawing. The peptide dosage calculator on this site can perform this calculation automatically.
Can I reconstitute multiple peptides in the same vial?
This is not recommended for research purposes. Mixing peptides in the same vial can cause interactions between compounds, makes it impossible to accurately dose individual components, and complicates research data interpretation. Each peptide should be reconstituted separately in its own vial with its own clearly labeled concentration.
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