Reconstitution is the process of adding liquid to a freeze-dried (lyophilized) peptide powder to create an injectable solution. Peptides ship as dry powder because they degrade quickly in liquid form. You mix them yourself right before you begin using them.
This guide covers the full process from equipment to injection-ready solution.
What You Need
Gather everything before you start. Working with a clean, organized surface reduces contamination risk.
Required equipment:
- Bacteriostatic water (BAC water) - Sterile water containing 0.9% benzyl alcohol as a preservative. This is the standard for multi-dose vials. Available in 10ml or 30ml vials.
- Insulin syringes - 1ml (100-unit) syringes with 29g or 30g needles for drawing and injecting. You need at least two: one for reconstitution, one for dosing.
- Alcohol swabs - 70% isopropyl alcohol pads for sterilizing vial tops.
- Peptide vial - Your lyophilized peptide. Should contain a small disc or puck of white/off-white powder at the bottom.
- Sharps container - For safe disposal of used needles. Never recap and reuse needles.
Optional but helpful:
- Nitrile gloves
- Clean paper towels or lint-free wipes
- A pen and label tape for marking vials with the reconstitution date
Step-by-Step Process
Step 1: Clean your workspace
Wipe down your surface with 70% isopropyl alcohol. Wash your hands thoroughly. Put on gloves if you have them.
Step 2: Let vials reach room temperature
Remove your peptide vial and BAC water from refrigeration. Let them sit for 5-10 minutes. Cold vials can cause pressure differences that make drawing water difficult.
Step 3: Determine your water volume
The amount of water you add determines your concentration. For example, adding 2ml of water to a 5mg vial of BPC-157 gives you 2,500mcg per ml (2.5mg/ml). Adding 1ml to the same vial gives 5,000mcg per ml.
More water means easier measurement of small doses. Less water means smaller injection volumes. Most peptides work well with 1-2ml. Check your peptide's recommended water volume on its calculator page.
Step 4: Swab the vial tops
Use a fresh alcohol swab on the rubber stopper of both the BAC water vial and the peptide vial. Let the alcohol dry for a few seconds. Do not blow on them.
Step 5: Draw bacteriostatic water
Insert the syringe needle into the BAC water vial. Tip the vial upside down. Pull the plunger back to your desired volume. Remove any air bubbles by tapping the syringe and pushing them back into the vial.
Step 6: Add water to the peptide vial
Insert the needle into the peptide vial at a slight angle. Do not aim the stream directly at the powder. Instead, let the water trickle down the inside wall of the vial. Push the plunger slowly. Rushing this step can damage the peptide.
Step 7: Let it dissolve
Do not shake the vial. Set it down and let the water work its way through the powder naturally. You can tilt the vial gently or roll it between your palms. Most peptides dissolve within 1-3 minutes. Some take up to 10 minutes.
The solution should be clear when fully dissolved. A slightly yellow tint is normal for some peptides (like GHK-Cu). Cloudiness or visible particles after 10 minutes of gentle swirling is a problem.
Step 8: Label and store
Write the peptide name, concentration, and today's date on the vial. Store immediately at 2-8°C (standard refrigerator). See our storage guide for full details.
Choosing Your Water Volume
The amount of BAC water you add controls your concentration, which affects how easy each dose is to measure. There is no single correct volume. It depends on your peptide amount and your typical dose size.
Why 1ml works for some setups: If your vial is small (like 2mg of DSIP), adding 1ml gives you 2,000mcg per ml. Your individual doses are still measurable on a 30-unit syringe. Less water also means smaller injection volumes, which some people prefer.
Why 2ml is the most common choice: For a 5mg vial of BPC-157, 2ml gives you 2,500mcg/ml. A typical 250mcg dose works out to 10 units on your syringe. That is easy to read on any syringe size. For a 10mg vial of TB-500, 2ml gives 5,000mcg/ml, putting common doses in the 5-20 unit range.
Why 3ml makes sense for larger vials: If you have a 10mg or 15mg vial and your doses are small relative to the total amount, 3ml spreads the concentration out. This makes it easier to measure precisely. A 10mg vial of CJC-1295/Ipamorelin with 3ml gives roughly 3,333mcg/ml. Small 100mcg doses come to about 3 units, which is readable on a 30-unit syringe.
General rule: pick a volume that puts your typical dose between 5 and 20 units on the syringe. Below 5 units you lose accuracy. Above 20 units you are injecting more liquid than necessary, which can be uncomfortable subcutaneously.
Use the peptide calculators on this site to test different water volumes before you reconstitute. You can see exactly how many units each dose will be.
Troubleshooting
Even when you follow every step, things can go sideways. Here is how to handle the most common problems.
Peptide won't dissolve. Some peptides take longer than others. GHK-Cu and MOTS-c can take a full 10 minutes. If it has been 10 minutes and you still see clumps, try gently rolling the vial between your palms for 30 seconds. The warmth from your hands can help. Do not add more water to speed things up. Do not shake. If the powder is still visibly undissolved after 15 minutes of patient swirling, the peptide may have been compromised before you received it (heat damage during shipping is the usual cause).
Air bubbles in the vial. Air bubbles in the peptide vial after adding water are harmless. They do not affect the peptide. They will rise to the surface and pop on their own within a few minutes. Air bubbles in your syringe are a different issue. See the syringe guide for how to remove them before injecting.
Solution looks cloudy. A clear solution is what you want. Slight haziness that clears within a minute or two of gentle swirling is fine. Persistent cloudiness after 10 minutes means something is wrong. The peptide may have been denatured (from heat exposure, shaking, or age), or the water may be contaminated. Do not inject a cloudy solution. Discard the vial.
Powder stuck to the rubber stopper. During shipping, some powder can migrate up to the underside of the stopper. When you add water, it may not reach that powder. Gently tilt the vial so the water contacts the stopper. You can also slowly invert the vial a few times. Avoid tapping or flicking the vial hard. The goal is to wet the stuck powder so it dissolves into the rest of the solution.
Water shoots back out when I insert the needle. This happens when there is positive pressure inside the vial. Before injecting the water, pull back on the syringe plunger to draw an equivalent volume of air into the syringe. Then inject that air into the peptide vial first. This equalizes the pressure. Now slowly push the water in. Some people also use a second needle inserted through the stopper as a vent.
I accidentally used too much or too little water. Too much water is not a problem. Your peptide is simply more diluted, so each unit on your syringe contains less peptide. Run the numbers through the calculator with your actual water volume and adjust your dose in units accordingly. Too little water is also fine. You just have a more concentrated solution. The peptide itself is not affected either way.
Common Mistakes
Shaking the vial. This is the most frequent error. Aggressive shaking creates bubbles and can denature the peptide's structure, reducing potency. Gentle swirling only.
Using the wrong water. Never use saline, distilled water from a store, or tap water. Only bacteriostatic water (for multi-dose vials) or sterile water for injection (for single-use). See our BAC water vs sterile water guide.
Squirting water directly onto the powder. The force of the stream can damage the peptide. Aim down the glass wall and let gravity do the work.
Reusing needles. Each needle dulls after a single use. A dull needle causes more tissue damage and increases infection risk. Use a fresh needle every time.
Not checking the vial before reconstituting. Look at your peptide powder before adding water. It should be a white or off-white disc or loose powder at the bottom of the vial. If it looks melted, discolored, or like a sticky residue instead of a dry puck, it may have been heat-damaged during shipping. Contact your supplier before reconstituting.
Forgetting to swab the stopper. The rubber stopper is not sterile after the factory seal is removed. Always swab with alcohol before every insertion.
Leaving reconstituted peptide at room temperature. Peptides degrade rapidly outside refrigeration. Put the vial back in the fridge as soon as you draw your dose. Even 30 minutes at room temperature repeatedly will shorten shelf life.
Storing the syringe pre-loaded. Drawing your dose into a syringe and saving it for later is a bad idea. The peptide can adsorb to the syringe barrel walls, and sterility is compromised once the cap is removed. Draw your dose right before you inject it.
After Reconstitution
Your peptide is now ready to dose. Use the calculator for your specific peptide to determine how many units to draw on your insulin syringe:
- BPC-157 calculator
- Semaglutide calculator
- Tirzepatide calculator
- TB-500 calculator
- CJC-1295/Ipamorelin calculator
Each calculator factors in your vial size, water volume, and desired dose to tell you exactly how many units to draw.