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How to reconstitute peptides: complete beginner's guide

How to reconstitute peptides: complete beginner's guide

Dec 16, 2025

How to reconstitute peptides
How to reconstitute peptides

You just got your first peptide vial.

It's a tiny bottle with white powder at the bottom.

No instructions or measurements.

Now what?

You know you need to add water.

But how much?

What kind?

How do you calculate doses afterward?

What if you screw it up?


Five minutes and you'll have injectable peptide ready to use. See how.


What reconstitution means

Reconstitution is mixing peptide powder with liquid to create an injectable solution.

Peptides are shipped as lyophilized powder because it's stable.

The powder can sit at room temperature during shipping without degrading.

Once you add water, the clock starts ticking, peptides in liquid form must be refrigerated and used within weeks.

Think of it like instant coffee.

Powder is stable forever, mix it with water, and you need to drink it relatively soon.

The powder → liquid process is reconstitution.


What you need before starting

Don't try to improvise. Get the right supplies first.

Essential items:

  • Your peptide vial (the powder)

  • Bacteriostatic water (BAC water) - NOT regular water

  • Alcohol prep pads

  • Insulin syringes (0.3ml or 0.5ml with 31G needle)

  • Sharps disposal container


Where to get supplies:

  • Bacteriostatic water: Online peptide vendors, Amazon, medical supply stores

  • Insulin syringes: Pharmacy (no prescription needed), Amazon, medical supply

  • Alcohol pads: Any pharmacy or Amazon

  • Sharps container: Pharmacy or Amazon


Cost for supplies:

  • Bacteriostatic water: $10-15 per 30ml bottle

  • Insulin syringes: $15-25 per 100-pack

  • Alcohol pads: $5-10 per 100-pack

  • Sharps container: $10-15

Total startup: $40-65. These supplies last for months of peptide use.


Why you must use bacteriostatic water

This is critical. Do not use regular sterile water.

Bacteriostatic water contains:

  • 99.1% sterile water

  • 0.9% benzyl alcohol (preservative)

The benzyl alcohol prevents bacterial growth. This lets reconstituted peptides last 28+ days in the refrigerator.


Regular sterile water:

  • No preservative

  • Bacteria can grow after opening

  • Reconstituted peptides only safe for 24 hours

  • Must be used same-day

Some peptides (like growth hormone) come with sterile water because you're supposed to use the entire vial immediately. But most peptides are used over weeks, so you need bacteriostatic water.


Never use:

  • Tap water (bacteria, contaminants)

  • Distilled water (no preservative)

  • Saline solution (wrong osmolarity for some peptides)

Only bacteriostatic water. This isn't optional.


How much water to add

The amount of water you add determines your concentration. More water = more dilute. Less water = more concentrated.

Neither is better. It's about convenience.

Standard ratios:

  • 2mg peptide + 2ml water = 1mg/ml (1000mcg/ml)

  • 5mg peptide + 2ml water = 2.5mg/ml (2500mcg/ml)

  • 5mg peptide + 1ml water = 5mg/ml (5000mcg/ml)

  • 10mg peptide + 2ml water = 5mg/ml (5000mcg/ml)


How to choose:

More water (2-3ml per vial):

  • Easier to measure small doses accurately

  • Larger injection volumes (0.2-0.3ml)

  • Lasts longer (more injections per vial)


Less water (1ml per vial):

  • Higher concentration

  • Smaller injection volumes (0.05-0.1ml)

  • Fewer injections per vial


Most people use 2ml of water for 5mg vials. This creates 2500mcg/ml concentration - easy math for calculating doses.

Our peptide reconstitution calculator does all the math for you. Enter your vial size and water amount, get exact concentration and dosing.


Step-by-step reconstitution process

Follow this exactly. No shortcuts.

Step 1: Prepare your workspace

Clean a flat surface. Wipe it down with alcohol or disinfectant.

Wash your hands thoroughly with soap and water. Dry them completely.

Gather all your supplies in one place.


Step 2: Prep the vials

Take your peptide vial and bacteriostatic water vial out of the refrigerator. Let them come to room temperature (10-15 minutes).

Cold liquid injected into cold powder can cause clumping.

Remove the plastic caps from both vials. Don't touch the rubber stoppers with your fingers.

Clean both rubber stoppers with alcohol prep pads. Let them air dry for 30 seconds.


Step 3: Draw bacteriostatic water

Take a new insulin syringe. Make sure the needle cap is on.

Remove the needle cap (keep the cap - you'll need it).

Pull back the plunger to the amount of water you want (usually 2ml = 200 units on insulin syringe).

Insert the needle through the rubber stopper of your bacteriostatic water vial.

Push the plunger down to inject air into the vial (this prevents vacuum).

Flip the vial upside down while keeping needle inserted.

Pull back the plunger to draw the exact amount of water you need.

Remove needle from vial. Recap the needle carefully (push cap onto needle, don't hold cap while pushing needle in).


Step 4: Add water to peptide vial

Hold your peptide vial at a 45-degree angle.

Insert the needle through the rubber stopper.

Critical step: Aim the needle at the side wall of the vial, NOT directly onto the powder.

Slowly inject the water down the side of the glass. Let it trickle down to the powder.

Do not spray water directly onto the powder. This can damage the peptide.

Remove the needle and dispose of the syringe in your sharps container.


Step 5: Dissolve the peptide

Do not shake the vial. Ever.

Let the vial sit undisturbed for 1-2 minutes. The powder will start dissolving on its own.

If some powder remains, gently swirl the vial in a circular motion. Don't shake or invert rapidly.

Within 2-5 minutes, the solution should be completely clear. No visible powder or particles.

If the solution is cloudy or has floating particles after 10 minutes, something went wrong. Do not use it.


Step 6: Store properly

Immediately place the reconstituted peptide in the refrigerator (36-46°F / 2-8°C).

Do not freeze. Freezing destroys peptides.

Label the vial with:

  • Peptide name

  • Concentration (mg/ml or mcg/ml)

  • Date reconstituted

  • Expiration (28 days from reconstitution)

Use a small piece of masking tape and a permanent marker.


Calculating your dose

Now you have reconstituted peptide. How do you figure out how much to inject?

The formula: Dose needed (mcg) ÷ Concentration (mcg/ml) = Volume to inject (ml)

Example 1: BPC-157

  • You need: 250mcg

  • Concentration: 2500mcg/ml (5mg + 2ml water)

  • Calculation: 250 ÷ 2500 = 0.1ml

  • Inject 0.1ml (10 units on insulin syringe)


Example 2: Semaglutide

  • You need: 500mcg (0.5mg)

  • Concentration: 2500mcg/ml (5mg + 2ml water)

  • Calculation: 500 ÷ 2500 = 0.2ml

  • Inject 0.2ml (20 units on insulin syringe)


Example 3: TB-500

  • You need: 2500mcg (2.5mg)

  • Concentration: 2500mcg/ml (5mg + 2ml water)

  • Calculation: 2500 ÷ 2500 = 1ml

  • Inject 1ml (entire syringe if using 1ml syringes)

Math not your thing?

Our peptide reconstitution calculator calculates injection volumes automatically.

Just enter your vial size, water amount, and desired dose.


Understanding insulin syringe measurements

Insulin syringes measure in units, not ml. This confuses people.

Standard conversions:

  • 100 units = 1ml

  • 50 units = 0.5ml

  • 10 units = 0.1ml

  • 5 units = 0.05ml

Most insulin syringes are marked in 1-unit increments. Each line is 0.01ml.


Common syringe sizes:

  • 0.3ml syringe = holds 30 units max

  • 0.5ml syringe = holds 50 units max

  • 1ml syringe = holds 100 units max

For most peptides, 0.3ml or 0.5ml syringes work perfectly.

Our calculator shows both ml and units, so you never have to do conversion math.


How to draw and inject

You've reconstituted correctly. Now let's use it safely.

Drawing from the vial

Clean the rubber stopper with an alcohol pad before every use.

Pull back the plunger to the amount you need to inject (creates air space).

Insert needle through rubber stopper into the vial.

Push plunger down to inject air into vial (prevents vacuum).

Flip vial upside down while keeping needle inserted.

Pull plunger back to draw your calculated dose.

Check for air bubbles. If present, tap syringe gently and push bubbles back into vial. Draw more liquid to replace the air.

Remove needle from vial. Recap carefully.


Injecting subcutaneously

Clean your injection site with alcohol pad. Let it dry completely (wet skin stings more).

Common injection sites:

  • Abdomen (easiest, most common)

  • Front/side of thigh

  • Back of upper arm

Pinch skin to create a fold.

Insert needle at 45-degree angle into the fat layer. Full depth of needle should go in.

Release the pinched skin.

Slowly inject over 5-10 seconds. Don't rush.

Remove needle at same angle it went in.

Apply light pressure with alcohol pad if needed. Don't rub.

Dispose of needle in sharps container immediately.


Rotating injection sites

Don't inject in the same spot repeatedly. This causes:

  • Scar tissue buildup

  • Reduced absorption

  • Lumps under the skin

  • Injection site pain


Create a rotation pattern. Example:

  • Monday: Left abdomen

  • Tuesday: Right abdomen

  • Wednesday: Left thigh

  • Thursday: Right thigh

  • Friday: Left abdomen (different spot)

Space injections at least 1 inch apart from previous sites.


Storage and shelf life

Proper storage determines how long your peptides remain effective.

Before reconstitution (powder):

  • Refrigerated: 12-24 months

  • Room temperature: 6-12 months

  • Frozen: Not recommended

Most peptide powder is stable at room temperature for shipping but should be refrigerated long-term.


After reconstitution (liquid):

  • Refrigerated (36-46°F): 28 days maximum

  • Room temperature: 24 hours maximum

  • Frozen: Never freeze reconstituted peptides

The 28-day rule applies to bacteriostatic water. Sterile water only lasts 24 hours.


Signs your peptide has degraded:

  • Solution becomes cloudy

  • Particles or flakes visible

  • Color changes (peptides should be clear)

  • Unusual smell

If you see any of these, discard the vial. Don't risk using degraded peptides.


Common reconstitution mistakes

Let's address what people screw up.

Mistake 1: Shaking the vial

Never shake peptide solutions. This denatures the peptide structure.

The delicate peptide chains can break apart from mechanical stress.

Gently swirl if needed. Be patient and let it dissolve naturally.


Mistake 2: Using wrong water

Bacteriostatic water only. Not sterile water, not saline, not tap water.

This mistake leads to bacterial contamination and wasted peptides.


Mistake 3: Spraying water directly onto powder

Aim for the glass wall, not the powder pile.

Direct spray can damage the peptide. Let water trickle down gently.


Mistake 4: Not letting vials reach room temperature

Cold water into cold powder causes clumping.

Wait 10-15 minutes for both vials to warm to room temperature before mixing.


Mistake 5: Storing at wrong temperature

Reconstituted peptides must be refrigerated.

Room temperature storage destroys them within 24 hours.

Freezing them destroys their structure.

36-46°F in refrigerator. That's it.


Mistake 6: Not sterilizing rubber stoppers

Every single time you insert a needle, wipe the stopper with alcohol first.

Bacteria on the stopper gets pushed into your vial with the needle.

One contaminated vial ruins your entire supply.


Mistake 7: Math errors in dosing

Concentration calculations confuse people.

Always convert mg to mcg (multiply by 1000) before calculating.

Use our peptide reconstitution calculator to eliminate math errors. It handles all conversions automatically.


Multi-dose vial management

Most peptide vials contain multiple doses. Manage them correctly.


Tracking doses remaining:

Let's say you have a 5mg BPC-157 vial reconstituted with 2ml water (2500mcg/ml concentration).

Your dose is 250mcg twice daily.


Math:

  • Total peptide: 5000mcg (5mg)

  • Dose per injection: 250mcg

  • Total doses available: 5000 ÷ 250 = 20 doses

  • Days the vial lasts: 20 doses ÷ 2 daily = 10 days

Mark on your vial or keep a log. When you have 2-3 doses left, prepare your next vial.


Multi-vial protocols:

For longer protocols, you'll use multiple vials.

Example: 8-week BPC-157 protocol (250mcg twice daily)

  • Doses needed: 2 per day × 56 days = 112 total doses

  • Doses per 5mg vial: 20 doses

  • Vials needed: 112 ÷ 20 = 5.6 vials (buy 6)

Our peptide cost calculator calculates exact vials needed for any protocol length and frequency.


Different peptides, different considerations

Some peptides need special attention.

Growth hormone peptides (Ipamorelin, CJC-1295)

These are fragile. Extra care needed:

  • Always aim water at glass wall

  • Never shake, even gently

  • Use within 21 days (not 28)

  • Check for cloudiness before each use


Large dose peptides (TB-500, semaglutide)

Higher doses mean faster vial depletion:

  • Consider larger vial sizes (10mg)

  • Or use less water for higher concentration

  • Track remaining doses carefully


Multiple daily dose peptides (BPC-157)

You'll access the vial 2x daily:

  • Extra important to sterilize stopper each time

  • Consider single-use reconstitution if doing 3x daily

  • Watch for contamination signs


Long-acting peptides (Semaglutide, CJC-1295)

One dose per week means vials last longer:

  • 28-day shelf life is plenty

  • Can use smaller water amounts for more concentrated solution

  • Less frequent contamination risk

Use our peptide dosage calculator to determine optimal dosing frequency and vial management for any peptide.


Troubleshooting common issues

Problems happen. Here's how to fix them.

Problem: Powder won't dissolve completely

Causes:

  • Water too cold

  • Not enough time

  • Damaged peptide


Solutions:

  • Let sit for 5-10 minutes undisturbed

  • Gently swirl (don't shake)

  • Warm hands around vial (body heat helps)

  • If still not dissolving after 15 minutes, peptide may be degraded


Problem: Solution is cloudy or has particles

Causes:

  • Contamination

  • Degraded peptide

  • Improper storage before reconstitution


Solutions:

  • Do not use cloudy solution

  • Discard the vial

  • Contact vendor for replacement

  • Never inject cloudy peptides


Problem: Can't draw liquid from vial

Causes:

  • Vacuum in vial

  • Needle blocked


Solutions:

  • Inject air into vial before drawing (equal amount to what you're withdrawing)

  • Make sure needle tip is below liquid level

  • Use fresh needle if current one is blocked


Problem: Injection site reactions

Causes:

  • Injecting too fast

  • Not rotating sites

  • Contaminated peptide


Solutions:

  • Inject slower (10 seconds minimum)

  • Rotate sites minimum 1 inch apart

  • Check for cloudiness before injection

  • If reactions persist, discard vial


Problem: Uncertain about concentration

Causes:

  • Forgot to label vial

  • Added wrong amount of water

  • Mixed up multiple vials


Solutions:

  • Always label immediately after reconstitution

  • Use our peptide reconstitution calculator and write exact concentration on vial

  • When uncertain, discard and start fresh (better safe than wrong dose)


Reconstitution for specific peptides

Quick reference for common peptides.

BPC-157 (5mg vial)

  • Water: 2ml bacteriostatic water

  • Concentration: 2500mcg/ml

  • Typical dose: 250mcg = 0.1ml (10 units)

  • Doses per vial: 20 injections

  • Use: BPC-157 dosage calculator


TB-500 (5mg vial)

  • Water: 2ml bacteriostatic water

  • Concentration: 2500mcg/ml

  • Typical dose: 2500mcg = 1ml (100 units)

  • Doses per vial: 2 injections

  • Use: TB-500 dosage calculator


Semaglutide (5mg vial)

  • Water: 2ml bacteriostatic water

  • Concentration: 2500mcg/ml (2.5mg/ml)

  • Starting dose: 250mcg = 0.1ml (10 units)

  • Maximum dose: 2400mcg = 0.96ml (96 units)

  • Use: Semaglutide dosage calculator


Ipamorelin (5mg vial)

  • Water: 2ml bacteriostatic water

  • Concentration: 2500mcg/ml

  • Typical dose: 200mcg = 0.08ml (8 units)

  • Doses per vial: 25 injections

  • Use: Peptide dosage calculator


Safety and sterile technique summary

The fundamentals that keep you safe:

Before reconstitution:

  • Wash hands thoroughly

  • Use clean workspace

  • Check peptide powder appearance (should be white/off-white)

  • Verify bacteriostatic water (not sterile water)


During reconstitution:

  • Clean both rubber stoppers with alcohol

  • Let vials reach room temperature

  • Inject water slowly down vial wall

  • Never shake, only gentle swirl

  • Verify complete dissolution before storing


After reconstitution:

  • Refrigerate immediately (36-46°F)

  • Label vial with name, concentration, date

  • Use within 28 days maximum

  • Check for cloudiness before each use


For every injection:

  • Clean rubber stopper with alcohol

  • Use new sterile syringe every time

  • Rotate injection sites

  • Dispose needles in sharps container

  • Track doses remaining

Follow these rules and you'll never have problems.


The bottom line

Reconstitution seems complicated until you do it once.

Then it's routine. Five minutes from powder to injectable peptide.

The keys:

  1. Bacteriostatic water only

  2. Inject water slowly down the wall

  3. Never shake the vial

  4. Refrigerate after mixing

  5. Use within 28 days


Get the calculations right using our peptide reconstitution calculator.

It eliminates math errors and shows exact injection volumes.

Once you've reconstituted correctly, you're ready to start your protocol with confidence.

The powder in that tiny vial is now medicine.

Use it right.


In case I don’t see you, good afternoon, good evening, and good night. Take care of yourself.

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peptdies

"I had struggled with acne for years and nothing worked. Was skeptical about peptides but decided to try the skin healing protocol SeekPeptides built for me. Within 6 weeks I noticed a huge difference, and by week 10 my skin was completely transformed. OMG, I still can't believe how clear it is now. Changed my life. Thanks."

— Emma S.

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peptides

“Used to buy peptides and hope for the best. Now I have a roadmap and I'm finally seeing results, lost 53 lbs so far.”

— Marcus T.

  • verified customer

peptides

"I'm 52 and was starting to look exhausted all the time, dark circles, fine lines, just tired. Started my longevity protocol 3 months ago and people keep asking if I got work done. I just feel like myself again."

— Jennifer K.

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