How to Reconstitute Peptides: Complete Step-by-Step Guide
Master the essential skill of peptide reconstitution. We cover what reconstitution is, why it matters, the complete process, calculations, equipment, storage, and common mistakes to avoid.
What is Peptide Reconstitution and Why Does It Matter?
Peptide reconstitution is the process of dissolving freeze-dried peptide powder into a liquid solvent to create an injectable or measurable solution. Most research peptides are manufactured and shipped as lyophilized powder because this form: (1) Is more stable during storage and shipping, (2) Resists degradation from heat and light, (3) Takes up less space, (4) Is easier to verify purity and composition.
However, peptides in powder form cannot be injected — they must be dissolved. Reconstitution converts the dry powder into a liquid solution with a known concentration (mg/mL), allowing accurate dosing and administration.
Why this matters: Improper reconstitution leads to: inaccurate dosing (too much or too little), contamination and injection site infections, peptide degradation and reduced effectiveness, wasted product, and safety issues. Proper technique ensures you're getting the full benefit of the peptide and minimizing health risks.
Equipment You'll Need
Essential supplies for reconstitution:
- Bacteriostatic water (BAC water): Sterile, pyrogen-free water with 0.9% benzyl alcohol. This is THE standard solvent for peptide reconstitution. Do not substitute with regular or distilled water.
- Sterile syringes: For drawing BAC water (3mL or 10mL syringes are typical). Use new, sealed syringes from pharmaceutical suppliers.
- Sterile needles: 25-27 gauge for drawing BAC water and injecting into the peptide vial. Single-use only.
- Alcohol swabs (70% isopropyl alcohol): For cleaning rubber stoppers on vials before access. Use new swab for each vial access.
- Insulin syringes (U100): For measuring final reconstituted peptide solution, especially for research peptides dosed in micrograms. Typically 0.3mL or 1mL capacity.
- Sterile gauge pads: For wiping around injection sites (optional but recommended).
- Alcohol prep pads: For disinfecting your work surface before reconstitution.
- Container for sharps disposal: A puncture-resistant container for used needles and syringes. Never throw sharps directly in trash.
- Vial labels: For labeling reconstituted peptides with date, concentration, and peptide name.
Where to obtain supplies: Pharmaceutical suppliers (Vitex, NEOGEN, Amazon Business), some local pharmacies, medical supply companies. Buy in bulk if you perform regular reconstitutions — sterile syringes and needles are inexpensive when purchased in quantity.
Step-by-Step Reconstitution Process
Step 1: Preparation
- Gather all supplies and lay them on a clean surface
- Wash your hands thoroughly with soap and water
- Disinfect your work area with an alcohol prep pad and let dry (approximately 30 seconds)
- Remove peptide vial from storage and allow it to reach room temperature if it was refrigerated (approximately 5-10 minutes)
- Remove BAC water vial from storage
- Verify expiration dates on both vials and alcohol swabs
- Calculate how much BAC water you need (see Calculation section below)
Step 2: Draw BAC Water
- Open a sterile syringe package (don't touch the barrel or plunger with bare hands)
- Attach a sterile 25-27 gauge needle to the syringe
- Remove the cap from the BAC water vial (or don't remove it — just work with the rubber stopper)
- Wipe the rubber stopper of the BAC water vial with an alcohol swab and allow to dry completely (this kills surface bacteria)
- Using the syringe and needle, draw the calculated volume of BAC water into the syringe. Make sure you draw slightly more than needed to account for the volume in the needle hub.
- Keep the needle sterile by keeping the cap on or not touching the tip
Step 3: Inject BAC Water into Peptide Vial
- Wipe the rubber stopper of the peptide vial with a fresh alcohol swab and let it dry completely
- Hold the peptide vial upright on a firm surface or in your non-dominant hand
- Using moderate pressure, insert the needle through the rubber stopper at a slight angle (not straight down) to avoid coring (creating a rubber particle)
- Slowly push the plunger to inject the BAC water into the vial
- Do NOT inject the BAC water directly onto the peptide powder — instead, aim for the side of the vial so the liquid runs down
- Keep the needle inserted in the vial
Step 4: Mixing the Solution
- Do NOT shake the vial vigorously — this can denature the peptide (damage its structure)
- Instead, gently swirl the vial in a circular motion for 30-60 seconds until the powder fully dissolves
- The solution should become clear. If it remains cloudy or particles are visible after 2-3 minutes of gentle swirling, continue swirling — some peptides take longer to fully dissolve.
- If the solution becomes foamy, let it sit for a few minutes to allow foam to dissipate
- Once fully dissolved, remove the needle from the vial and discard it in your sharps container
Step 5: Verify and Label
- Hold the vial up to the light and inspect for cloudiness, discoloration, or particles — the solution should be clear and colorless
- Verify the concentration is correct (e.g., 100 mcg/mL for BPC-157, 200 mcg/mL for sermorelin)
- Label the vial with: peptide name, concentration (mg/mL or mcg/mL), date of reconstitution, expiration date, and your initials
- Store according to the peptide's requirements (usually room temperature or refrigerated)
Discard sharps properly: All used needles and syringes go into a puncture-resistant sharps container. Never throw them in regular trash where they could injure sanitation workers.
Reconstitution Calculations: Math Made Simple
The fundamental formula for reconstitution is:
Concentration (mg/mL) = Peptide Amount (mg) ÷ Volume of Solvent (mL)
Example 1: BPC-157
- You have: 10mg of BPC-157 powder
- Desired concentration: 100 mcg/mL (0.1 mg/mL)
- Calculation: 10mg ÷ 0.1 mg/mL = 100mL of BAC water needed
- Result: Add 100mL of BAC water to 10mg BPC-157 powder to create a 100 mcg/mL solution
Example 2: Sermorelin
- You have: 10mg of sermorelin powder
- Desired concentration: 200 mcg/mL (0.2 mg/mL)
- Calculation: 10mg ÷ 0.2 mg/mL = 50mL of BAC water needed
- Result: Add 50mL of BAC water to 10mg sermorelin to create a 200 mcg/mL solution
Example 3: Ipamorelin
- You have: 5mg of ipamorelin powder
- Desired concentration: 500 mcg/mL (0.5 mg/mL) for easier dosing
- Calculation: 5mg ÷ 0.5 mg/mL = 10mL of BAC water needed
- Result: Add 10mL of BAC water to 5mg ipamorelin to create a 500 mcg/mL solution
Converting micrograms to milligrams: 1 milligram (mg) = 1,000 micrograms (mcg). So 100 mcg/mL = 0.1 mg/mL.
Pro tip: Reconstitute to higher concentrations if possible, as this reduces the injection volume needed. For example, 500 mcg/mL requires a smaller injection volume than 100 mcg/mL, making dosing more convenient and reducing needle trauma to injection sites. However, higher concentrations may affect solution stability — check the peptide supplier's recommendations.
10 Common Reconstitution Mistakes to Avoid
- Using non-sterile water: Tap water, distilled water, or saline without benzyl alcohol preservative. Always use pharmaceutical-grade BAC water.
- Not documenting concentration: Forgetting to label the vial with the concentration leads to dosing errors. Always label immediately after reconstitution.
- Shaking the vial vigorously: High-energy shaking can denature peptides, reducing their effectiveness. Use gentle swirling only.
- Injecting BAC water directly onto powder: This can create a "mud" that doesn't dissolve well. Instead, inject the liquid down the side of the vial.
- Using expired supplies: Expired BAC water, syringes, or needles lose sterility guarantees. Always check expiration dates.
- Not using sterile technique: Touching needle tips, reusing needles, or failing to clean rubber stoppers introduces bacteria. Contamination leads to infection.
- Reconstituting in excessive quantities: Peptides degrade over time. Reconstitute only 1-2 weeks' worth at a time to maintain potency.
- Freezing reconstituted solutions: Ice crystals can damage peptide structure. Freezing should be avoided unless the peptide specifically allows it (check supplier guidelines). Refrigeration is safer.
- Not letting rubber stopper dry after alcohol wipe: Injecting alcohol into the vial can damage the peptide solution. Let alcohol evaporate completely (approximately 30 seconds) before injecting.
- Using the same needle for drawing BAC water and injecting into peptide vial: While possible, using separate needles reduces the risk of coring the rubber stopper and maintains better sterile technique. Use one needle to draw, discard it, use a fresh needle to inject.
Storage Guidelines for Reconstituted Peptides
Room temperature storage (68-72°F): Reconstituted peptides in BAC water remain stable for approximately 2-4 weeks at room temperature. The benzyl alcohol preservative inhibits bacterial growth, but peptide molecules still degrade over time.
Refrigeration (35-46°F): Refrigerated peptides typically remain stable for 6-12 weeks. This is the preferred storage method for most research peptides. Store in a dark place (a box in the refrigerator is ideal) to protect from light exposure, which degrades some peptides.
Freezing (below -18°C): Frozen reconstituted peptides may last 6-12 months, but freezing is NOT recommended because: (1) Ice crystals form and can damage peptide structure, (2) Thawing and refreezing is harmful — avoid multiple freeze-thaw cycles, (3) Most peptides remain potent in refrigeration for months, making freezing unnecessary.
Signs of degradation (discard immediately):
- Solution becomes cloudy or develops visible particles
- Color changes (unusual discoloration)
- Unusual odor
- Visible mold or growth on/around vial
- If stored past the recommended expiration date
Preventing evaporation: Seal the vial tightly after each use. Over weeks, water evaporates from open or loosely-sealed vials, concentrating the solution and potentially altering the dose. A properly sealed vial minimizes evaporation.
Maintaining Sterility: Best Practices
Bacterial contamination is the most serious risk during reconstitution. Contaminated solutions can cause injection site infections, cellulitis, or systemic infections. Follow these practices:
Hand hygiene: Wash hands thoroughly with soap and warm water for at least 20 seconds before handling peptides. Avoid touching your face or other body parts during reconstitution.
Work surface preparation: Clean your work area with 70% isopropyl alcohol or a disinfectant wipe. Allow to air dry (this ensures the alcohol has time to kill surface bacteria).
Rubber stopper cleaning: The rubber stoppers on vials are common contamination sites. Wipe with a fresh alcohol swab before each access (drawing BAC water, injecting BAC water, or drawing reconstituted peptide). Allow 30 seconds for the alcohol to evaporate — don't inject while the stopper is still wet with alcohol.
Needle and syringe safety: Use only sterile, single-use needles and syringes. Never reuse needles. If a needle touches your skin, your work surface, or any non-sterile object, discard it immediately and use a fresh needle. This is non-negotiable.
Minimize open-air exposure: Work quickly and efficiently. The longer your vial is open to air, the greater the contamination risk. Keep all supplies sealed until the moment of use.
Proper capping of vials: Between uses, keep the vial capped to prevent bacterial entry from the air. Each time you access the vial, use a clean alcohol swab on the rubber stopper.
Peptide-Specific Reconstitution Examples
BPC-157 (Body Protection Compound-157)
- Typical vial: 10mg
- Typical concentration: 100 mcg/mL
- BAC water needed: 100mL
- Typical dose: 250-500 mcg daily (2.5-5mL per injection if using 100 mcg/mL concentration)
- Storage: Refrigerate
- Typical vial: 10mg
- Typical concentration: 200-250 mcg/mL
- BAC water needed: 40-50mL for 200 mcg/mL concentration
- Typical dose: 100-200 mcg daily
- Storage: Refrigerate or room temperature
- Typical vial: 5mg or 10mg
- Typical concentration: 500 mcg/mL (allows smaller injection volumes)
- BAC water needed: 10mL for 5mg or 20mL for 10mg
- Typical dose: 200-300 mcg daily
- Storage: Refrigerate
Note: Always follow the specific peptide supplier's reconstitution recommendations, as some peptides have unique requirements. The above are general guidelines based on common research peptide concentrations.
Troubleshooting Reconstitution Problems
Problem: Peptide powder won't dissolve
Solutions: (1) Continue gentle swirling for several more minutes — some peptides dissolve slowly, (2) Ensure BAC water is at room temperature (cold water dissolves peptides more slowly), (3) Verify you used sterile, pharmaceutical-grade BAC water (contaminated or non-sterile water may cause precipitation), (4) Check that you calculated the correct volume of BAC water (too little water means incomplete dissolution).
Problem: Solution is cloudy after reconstitution
Possible causes: (1) Bacterial contamination (discard and start over with sterile technique), (2) Peptide degradation (vial may have been improperly stored before reconstitution), (3) Alcohol residue in the vial (ensure rubber stopper was fully dry before injecting BAC water), (4) Contaminant in BAC water (use fresh, sealed BAC water bottle).
Problem: I created too much reconstituted peptide and it's degrading
Prevention: In the future, reconstitute smaller quantities — enough for 1-2 weeks of use only. If already reconstituted, store refrigerated immediately and use as quickly as possible. Do not freeze unless you understand the specific peptide's freeze-thaw tolerance.
Problem: I don't remember how much BAC water I used (forgot to label)
Prevention: Always label immediately after reconstitution. If this happens now, you cannot reliably determine the concentration. Either: (1) Calculate based on how much BAC water the bottle used (if you can measure what's left), or (2) Discard and start over. Dosing based on an unknown concentration is unsafe.
Important Safety Notes
For research use only: Most peptides in this guide are considered research peptides and should not be used for clinical purposes without medical supervision. They have not undergone FDA approval for human use and lack the extensive safety data of pharmaceutical medications.
Infection risk: Improper reconstitution technique or contamination can lead to bacterial infections. Symptoms include redness, warmth, swelling, or pus at the injection site; fever; or systemic illness. Seek medical attention immediately if infection is suspected.
Allergic reactions: Some individuals may be allergic to peptides or components of the solution. If you experience hives, difficulty breathing, throat swelling, or severe reactions, seek emergency medical attention.
Medical supervision: Ideally, peptide use should be done under medical supervision with regular check-ins to monitor for adverse effects, infections, or complications.
Frequently Asked Questions
Reconstitution is the process of dissolving lyophilized (freeze-dried) peptide powder into a liquid solvent, typically bacteriostatic water (BAC water), to create an injectable solution. Most research peptides are shipped as dry powder because it's more stable for storage and transport. Before use, you mix the powder with a sterile liquid to create a solution that can be measured and administered via injection.
BAC (bacteriostatic) water is sterile, pyrogen-free water containing 0.9% benzyl alcohol as a preservative. It's used for reconstitution because: (1) The benzyl alcohol inhibits bacterial growth, keeping the reconstituted solution sterile longer, (2) It's isotonic (same osmolarity as blood), making it safe for injection, (3) It's sterile and pyrogen-free, reducing infection risk. Never use regular distilled water, tap water, or saline — these lack the preservative properties and sterility guarantees of pharmaceutical-grade BAC water.
The basic calculation: concentration (mg/mL) = peptide amount (mg) ÷ BAC water volume (mL). Example: If you have 10mg of a peptide and want a 1mg/mL solution, you divide 10mg ÷ 1mg/mL = 10mL of BAC water needed. For higher concentration (5mg/mL): 10mg ÷ 5mg/mL = 2mL BAC water. Higher concentrations mean smaller volumes and more concentrated solutions, which requires smaller injections. Always document your calculations and final concentration on the vial label for future reference.
Use insulin syringes (U100, typically 0.3mL or 1mL) for accurate small-volume measurements, especially for research peptides typically dosed in micrograms. For reconstitution (adding BAC water to powder), use a slightly larger needle (25-27 gauge) to draw liquid without coring the rubber stopper. For injection, use 25-30 gauge needles for subcutaneous injections, or 21-23 gauge for intramuscular if appropriate. Never reuse needles — use fresh needles for each draw and injection. Sterile, single-use syringes and needles are essential for safety.
Technically yes, sterile saline is isotonic and won't harm tissue, but it's not ideal for storing reconstituted peptides. Saline lacks the bacteriostatic preservative (benzyl alcohol) that BAC water contains, so reconstituted peptides in saline must be used within hours or refrigerated. BAC water's benzyl alcohol preservative keeps peptide solutions sterile for weeks when properly stored. For research purposes where you'll use the entire reconstituted dose immediately, saline works, but BAC water is the better choice for shelf stability.
Common mistakes include: (1) Using non-sterile water or tap water — risk of infection and contamination, (2) Not documenting the concentration — leading to dosing errors later, (3) Reconstituting too much at once — unused portion may degrade, (4) Using expired BAC water — loses sterility guarantee, (5) Injecting too fast after reconstitution — peptide may not fully dissolve, (6) Not using sterile technique — increases contamination and infection risk, (7) Recapping the needle and vial repeatedly — introduces bacteria, (8) Freezing reconstituted peptides — can damage the solution structure and reduce effectiveness.
With proper storage, reconstituted peptides in BAC water typically last: Room temperature (68-72°F): 2-4 weeks before significant degradation. Refrigerated (35-46°F): 6-12 weeks. Frozen (-18°C or colder): 6-12 months, though freezing may reduce effectiveness due to ice crystal formation. The specific duration depends on the peptide's stability profile — more fragile peptides degrade faster. Always store in a sealed vial to prevent contamination and evaporation. If reconstituted solution becomes cloudy, discolored, or smells unusual, discard it — these signs indicate contamination or degradation.
No, reconstitute only the amount you'll use within your intended timeframe. Reasons: (1) Peptides degrade over time — reconstituting excess wastes product, (2) Each time you draw from the vial, you risk introducing bacteria even with sterile technique, (3) Evaporation occurs over weeks, changing concentration, (4) Some peptides are sensitive to freeze-thaw cycles if frozen and later thawed. Best practice: reconstitute small amounts (1-2 weeks' worth of doses) weekly or as needed. This maintains maximum peptide stability and concentration accuracy.
Sterile technique means all materials contacting the peptide solution remain free of bacteria and microorganisms. Steps: (1) Clean your work surface with 70% isopropyl alcohol, (2) Wash hands thoroughly with soap and water, (3) Use new, sealed alcohol wipes to clean the rubber stopper of both the peptide vial and BAC water vial before each access, (4) Never touch the needle tip or plunger with bare hands, (5) Only use sterile, single-use needles and syringes, (6) Keep the needle capped until use, (7) Work quickly to minimize open-air exposure, (8) If the needle touches your skin, your work surface, or anything non-sterile, discard it and use a fresh needle. Good sterile technique is the #1 way to prevent bacterial contamination and injection site infections.
Disclaimer: This guide is for informational and educational purposes only. Most research peptides are not FDA-approved for human use. This guide does not constitute medical advice. Peptide reconstitution and use should only be performed by individuals with appropriate training and, ideally, under medical supervision. Do not use peptides as a substitute for professional medical treatment. Always consult a healthcare provider before using any peptide therapy. Improper reconstitution or injection can result in infection, allergic reactions, or other adverse effects. Follow all safety protocols and sterile technique guidelines.