How to Reconstitute Peptides: Complete Step-by-Step Guide
Peptide reconstitution is the process of dissolving lyophilized (freeze-dried) powder into a measured liquid so every draw is predictable. Peptides ship in powder form for stability, easier transport, and dosing flexibility. This guide covers supplies, concentration math, bacteriostatic water versus sterile water, a detailed 8-step mixing method, troubleshooting, storage, and peptide-specific examples for BPC-157, semaglutide, tirzepatide, retatrutide, TB-500, and CJC-1295/Ipamorelin.
Keep this open while you mix and use the PepPal reconstitution calculator to convert mg, mL, and syringe units instantly.
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Quick Answer
Quick answer: Peptide reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide into bacteriostatic water to create a measurable solution. Clean the vial tops with alcohol, slowly inject BAC water down the inside wall of the vial, gently swirl until dissolved, then label and refrigerate. Use a reconstitution calculator for exact concentrations.
What You Need to Reconstitute Peptides
A complete supply setup eliminates most avoidable mistakes. Prep every item before you puncture a vial so you can focus on sterile flow and accurate measurements.
| Supply | What It Is For | Essential? | Where to Get |
|---|---|---|---|
| Lyophilized peptide vial | The peptide you are reconstituting | Required | Trusted suppliers |
| Bacteriostatic water | Solvent with preservative for multi-dose use | Required | Amazon |
| Insulin syringes (29-31G) | Drawing doses and measuring units accurately | Required | Amazon search |
| Mixing syringe + blunt tip (18-22G) | Transferring BAC water into peptide vial | Required | Amazon search |
| Alcohol prep pads | Sanitizing vial stoppers before each puncture | Required | Amazon |
| Nitrile gloves | Cleaner handling and lower contamination risk | Recommended | Amazon |
| Labels + marker | Tracking concentration, date, and peptide name | Recommended | Amazon |
| Sharps container | Safe disposal for used syringes and needles | Recommended | Amazon |
| Storage case | Organizing vials and accessories in the fridge | Optional | Amazon |
For a complete equipment list with product links, see our peptide injection supplies checklist.
Bacteriostatic Water vs Sterile Water: Which Should You Use?
This is a critical decision point. For multi-dose peptide handling, bacteriostatic water is usually preferred because it includes preservative support after repeated punctures.
| Feature | Bacteriostatic Water | Sterile Water |
|---|---|---|
| Preservative | 0.9% benzyl alcohol | None |
| Multi-dose use | Yes | No, single use only |
| Shelf life after opening | 28 days | Use immediately, discard remainder |
| Bacterial protection | Benzyl alcohol inhibits growth | None |
| pH | ~5.7 (4.5 to 7.0) | ~7.0 (neutral) |
| Best for | Most peptide reconstitution workflows | Single-dose one-time preparation |
| Cost | $8-12 per 30 mL vial | $2-5 per 10 mL ampule |
Key point: Use bacteriostatic water unless the peptide documentation explicitly requires sterile water. The preservative is what supports repeated draws from the same vial.
If you must use sterile water, plan for single-use or very short handling windows and minimize puncture count.
Peptide Reconstitution Math: Concentration, Volume & Dosing
Accurate concentration math is what turns a powder vial into repeatable dose measurements. Keep one formula in front of you and verify every unit before drawing.
Total peptide (mg) / Diluent volume (mL) = Concentration (mg/mL)
| Peptide (mg) | BAC Water (mL) | Concentration (mg/mL) | Concentration (mcg/mL) | Per 10 units (0.1 mL) |
|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 5,000 mcg/mL | 500 mcg |
| 5 mg | 2 mL | 2.5 mg/mL | 2,500 mcg/mL | 250 mcg |
| 10 mg | 1 mL | 10 mg/mL | 10,000 mcg/mL | 1,000 mcg |
| 10 mg | 2 mL | 5 mg/mL | 5,000 mcg/mL | 500 mcg |
| 10 mg | 3 mL | 3.33 mg/mL | 3,333 mcg/mL | 333 mcg |
| 15 mg | 3 mL | 5 mg/mL | 5,000 mcg/mL | 500 mcg |
| 30 mg | 3 mL | 10 mg/mL | 10,000 mcg/mL | 1,000 mcg |
How to Read an Insulin Syringe
- U-100 syringe: 100 units = 1 mL
- 10 units = 0.1 mL
- Each tick mark = 1 unit (0.01 mL)
- Pro tip: if your target dose is under 5 units, add more BAC water so measurement precision improves.
Skip manual conversions and use the free reconstitution calculator to get exact syringe units instantly.
How to Reconstitute Peptides: 8-Step Process
Follow this sequence every time. Most reconstitution issues trace back to skipping prep, rushing injection speed, or poor labeling.
Step 1: Prepare Your Workspace
- Clean a flat surface with 70% isopropyl alcohol and let it dry fully.
- Lay out every supply before puncturing any vial so you do not need to search mid-process.
- Wash hands with soap and water for at least 20 seconds, then put on nitrile gloves.
- Work in a low-traffic area away from vents, fans, and open windows to reduce airborne particles.
- Keep your PepPal calculator result open so your target volume and units are ready.
Step 2: Calculate Your Target Concentration
- Use the PepPal calculator to confirm how much BAC water to add and what final concentration you will create.
- Write down four values before touching the vials: peptide mg, BAC water mL, target mcg per dose, and syringe units per dose.
- Double-check mg versus mcg conversions now. Most dosing mistakes happen from unit mix-ups before mixing even starts.
Skip manual math when possible. Open the calculator and lock in your exact ratio before you draw liquid.
Step 3: Sanitize the Vial Tops
- Remove only the flip-off plastic caps from both vials. Do not remove the aluminum crimp seal.
- Wipe each rubber stopper thoroughly using alcohol pads in one direction.
- Allow the stoppers to air dry for 10 to 15 seconds. Do not blow on them.
- If the stopper touches a non-sterile surface, sanitize again before puncturing.
Never skip vial-top sanitization. The rubber stopper is the most common contamination point.
Step 4: Draw the Bacteriostatic Water
- Pull the plunger back first to draw air equal to the BAC water volume you plan to withdraw.
- Insert the needle into the BAC water vial and inject that air before drawing liquid.
- Invert the vial and slowly draw the calculated BAC water volume.
- Tap the syringe lightly to float bubbles to the top, then push out excess air.
- Reconfirm the final volume at eye level before moving to the peptide vial.
Step 5: Inject Water into the Peptide Vial Using the Pouring-a-Beer Technique
- Insert the needle through the peptide vial stopper and angle the tip toward the inside glass wall.
- Depress the plunger slowly so water trickles down the wall instead of blasting the powder puck.
- Keep the flow gentle from start to finish. A hard stream can stress fragile peptide chains.
- After the full volume is transferred, pause briefly to let pressure settle in the vial.
Never spray liquid directly onto the powder and never shake the vial. Both can denature peptides.
Step 6: Vent the Vial (Pro Tip)
- When you add 1 to 3 mL, the vial often builds positive pressure that makes later draws harder.
- Before removing the mixing syringe, insert a second empty needle for 2 to 3 seconds.
- This vents compressed air and equalizes pressure for smoother future draws.
- Remove the vent needle first, then remove the mixing syringe.
Venting is optional, but it noticeably improves dose-draw consistency in multi-dose vials.
Step 7: Dissolve the Peptide
- Most powders dissolve in 1 to 5 minutes with no force if the liquid was added gently.
- If powder remains, swirl the vial in a slow circular motion or roll it between your palms.
- Let the vial rest in the refrigerator for 15 to 30 minutes if needed.
- The final solution should be clear and colorless. Cloudiness or persistent particles are warning signs.
Step 8: Label and Store
- Label the vial immediately with peptide name, concentration, reconstitution date, and 28-day discard date.
- Store the vial in a refrigerator at 2 to 8 C (36 to 46 F).
- Keep the vial protected from light by using the original box or foil wrap.
- Wipe the stopper with alcohol every time before drawing a dose.
Reconstitution by Peptide Type
These examples target common long-tail queries and show why concentration planning matters per compound. Always validate with your source documentation before mixing.
How to Reconstitute BPC-157
| Common vial | 5 mg |
|---|---|
| BAC water | 2 mL |
| Concentration | 2,500 mcg/mL |
| Common dose | 250-500 mcg (10-20 units) |
BPC-157 usually dissolves quickly, often within 30 to 60 seconds. It is generally considered one of the more stable peptides in routine reconstitution workflows. Even with that stability, keep sterile technique strict and keep the vial cold after mixing.
How to Reconstitute Semaglutide
| Common vial | 5 mg |
|---|---|
| BAC water | 2 mL |
| Concentration | 2,500 mcg/mL |
| Common dose | 250 mcg start (10 units) |
Semaglutide may take 2 to 5 minutes to fully dissolve depending on temperature and handling. Many protocols start low and escalate over time, so concentration accuracy matters from the first mix. Track every draw in your log to avoid cumulative unit drift.
How to Reconstitute Tirzepatide
| Common vial | 5 mg or 10 mg |
|---|---|
| BAC water | 1 mL per 5 mg |
| Concentration | 5,000 mcg/mL |
| Common dose | 2,500 mcg start (protocol dependent) |
Tirzepatide is commonly mixed at higher concentration to keep injection volume low. Strict protocol spacing is typically used with at least 4 weeks between increases in many research schedules. Maintain consistent BAC water ratios across vials so unit math remains predictable.
How to Reconstitute Retatrutide
| Common vial | 5 mg or 10 mg |
|---|---|
| BAC water | 1 mL per 5 mg |
| Concentration | 5,000-10,000 mcg/mL |
| Common dose | Protocol-specific |
Retatrutide is newer and users often report slower dissolution times around 3 to 5 minutes. Let the vial rest if small particles remain instead of forcing the process. Because sourcing quality varies, pair reconstitution discipline with strict supplier verification.
How to Reconstitute TB-500
| Common vial | 5 mg |
|---|---|
| BAC water | 1 mL |
| Concentration | 5,000 mcg/mL |
| Common dose | 2,000-2,500 mcg |
TB-500 usually dissolves rapidly when water is added along the wall. Because many users mix this peptide at concentrated ratios, verify syringe units carefully before each draw. Labeling and refrigeration timing are still essential for stability.
How to Reconstitute CJC-1295 / Ipamorelin
| Common vial | 2 mg blend or 5 mg blend |
|---|---|
| BAC water | 2 mL |
| Concentration | Blend-dependent |
| Common dose | 100-300 mcg |
Blended vials need careful documentation because two actives share one concentration table. Keep the same reconstitution ratio for each new vial so dose tracking stays clean between cycles. Many protocols time administration around fasting windows, so schedule notes can reduce errors.
8 Reconstitution Mistakes That Ruin Your Peptides
- Spraying water directly onto powder: A high-pressure stream can physically stress peptide material. Always run water down the vial wall for a gentle fill.
- Shaking the vial: Aggressive shaking creates foam and shear forces that can damage peptide chains. Swirl or roll slowly instead.
- Using the wrong solvent: Tap, distilled, or bottled water are not sterile injectable solvents. Use bacteriostatic water unless documentation says otherwise.
- Skipping stopper sanitization: Every puncture is a contamination opportunity. Wipe the stopper before each needle entry, not only the first time.
- Reusing needles between vials: Cross-contamination risk jumps when a used needle moves from one vial to another. Keep needles single-use.
- Mixing up mg, mcg, and mL: Unit confusion creates major dose errors. Write units with every number and confirm conversion before each draw.
- Leaving reconstituted vials at room temperature: Warm storage accelerates degradation. Reconstituted peptides should go back to refrigeration immediately.
- Using expired BAC water: Opened bacteriostatic water should be discarded after 28 days from first puncture. After that, preservative protection is unreliable.
How to Store Reconstituted Peptides
| Form | Temperature | Shelf Life | Key Notes |
|---|---|---|---|
| Lyophilized (powder) | -20 C to 4 C | 12-24+ months | Freezer preferred for longest stability |
| Reconstituted (liquid) | 2-8 C (fridge) | Up to 28 days | Do not freeze, protect from light |
| BAC water (opened) | Room temp or fridge | 28 days after first puncture | Discard after day 28 |
| BAC water (sealed) | Room temperature | Until manufacturer expiry | Confirm expiration before use |
- Refrigerate immediately after reconstitution.
- Keep vials upright and protected from light.
- Never freeze reconstituted peptides because ice crystals can damage structure.
- Minimize repeated freeze-thaw cycles for lyophilized powders.
- Label every vial with name, concentration, date, and discard date.
- Use a dedicated storage case to keep compounds and tools organized.
Troubleshooting: What If Something Goes Wrong?
My solution is cloudy after reconstitution
Cloudiness can indicate aggregation from rough handling or poor solvent compatibility. Gently swirl and let the vial rest 15 to 30 minutes. If cloudiness remains, do not use the vial and contact your supplier.
The powder will not dissolve
Some compounds need more time. Swirl gently, avoid shaking, and let the vial rest in the refrigerator for 15 to 30 minutes. If undissolved material persists after 30+ minutes, treat the vial as compromised.
I see foam or bubbles
Foam usually comes from injecting too quickly. Let the vial sit 10 to 15 minutes to settle. Small bubbles are common; persistent dense foam is a warning sign that mixing force may have been too high.
I accidentally sprayed water onto the powder
If the final solution remains clear, it may still be usable for research workflows. Next time, angle the needle toward the vial wall to avoid direct impact. If cloudiness appears, discontinue use and replace.
Air pressure makes draws difficult
Use a vent needle for 2 to 3 seconds after adding liquid, or inject a small amount of air to equalize pressure before drawing. Pressure balance improves draw smoothness and reduces sudden plunger jumps.
I see floating particles or precipitation
This can happen when a solution is mixed too concentrated for that peptide. You can try adding a small amount of BAC water and gently swirling. If particles remain after 30 minutes, treat the vial as degraded.
Frequently Asked Questions About Peptide Reconstitution
How do you reconstitute peptides?
What supplies do you need to reconstitute peptides?
How much bacteriostatic water should I use?
How do I calculate concentration after reconstitution?
Can you reconstitute peptides with sterile water?
How long do reconstituted peptides last?
Do peptides need to be refrigerated after reconstitution?
Is peptide reconstitution the same as dilution?
What happens if you shake a peptide vial?
How do you know if a reconstituted peptide has gone bad?
Can you freeze reconstituted peptides?
How many times can you draw from a reconstituted peptide vial?
What is the difference between a mixing syringe and an injection syringe?
Do I need to remove the aluminum cap from the peptide vial?
Can I reconstitute peptides with acetic acid?
Why does my peptide vial look empty before mixing?
Can I use regular bottled or distilled water to mix peptides?
Reconstitution Calculator
Skip the math. Enter your peptide amount, BAC water volume, and target dose to see exactly how many syringe units to draw.