How to Reconstitute and Store Peptides: Complete Guide

If you've just received your first peptide vials and you're staring at a tiny pile of white powder wondering what to do next, you're in the right place. Reconstituting peptides sounds complicated but it really isn't. Once you've done it a couple of times, the whole process takes about five minutes.

The thing is, getting it wrong can destroy an expensive vial of peptides in seconds. Shake too hard, use the wrong water, store it at the wrong temperature, and you've just wasted your money. We see this happen all the time with first-time buyers.

This guide covers everything from mixing your peptides to calculating exact dosages, proper injection technique, and long-term storage. We've included a peptide dosage calculator with worked examples for every popular peptide we sell, including BPC-157, TB-500, GHK-Cu, Semaglutide, and more. Bookmark this page. You'll come back to it.

What You Need Before Starting

Before you touch a peptide vial, make sure you've got everything laid out on a clean surface. Stopping halfway through to rummage through drawers is a contamination risk you don't need.

Here's your equipment checklist:

• Bacteriostatic water (BAC water) - This is non-negotiable. BAC water contains 0.9% benzyl alcohol which prevents bacteria from growing in your reconstituted solution. Some people ask about using sterile water instead. Don't. Sterile water has no preservative, which means bacteria can start colonising your vial within hours of the first needle puncture. If you're using the vial over multiple days or weeks (which you will be), you need the antibacterial protection that BAC water provides. Sterile water is fine for single-use situations, but for multi-dose peptide vials, bacteriostatic water is the only sensible choice.
• Alcohol swabs - For cleaning vial stoppers and injection sites. Standard 70% isopropyl alcohol swabs work perfectly. Buy them in bulk, there cheap as chips.
• Insulin syringes (29-31 gauge) - These are the thin, short-needled syringes designed for subcutaneous injection. 29 gauge is the most common. 31 gauge is thinner and some people prefer them for comfort, though they draw liquid a bit slower. Get the 1ml size with markings in "units" (100 units = 1ml).
• Peptide vials - Your lyophilised (freeze-dried) peptide powder. Keep these refrigerated until you're ready to reconstitute.
• Sharps container - A proper sharps bin for used needles. Never throw syringes in regular bins. Most pharmacies will give you one for free or very cheap, and many local councils offer free sharps disposal services across the UK.

Optional but helpful: a larger syringe (3ml or 5ml) for drawing up bacteriostatic water if you're adding larger volumes. Some people find it easier than drawing 2ml with a tiny insulin syringe.

Step-by-Step: How to Reconstitute Peptides

Right, let's get into it. Follow these steps carefully the first time. After a few goes it becomes second nature.

Step 1: Let your vials reach room temperature.

Take your peptide vial and your bacteriostatic water out of the fridge and leave them on the counter for 15-20 minutes. You don't want to work with cold vials because the temperature difference can cause condensation, and the powder reconstitutes more smoothly at room temp.

Step 2: Wash your hands and clean the vial stoppers.

Wash your hands thoroughly with soap and water. Then take an alcohol swab and wipe the rubber stopper on both your peptide vial and your BAC water vial. Let them air dry for about 10 seconds. Don't blow on them.

Step 3: Equalise pressure in the peptide vial.

Most guides skip this, but it makes a massive difference. Peptide vials are often sealed under vacuum, so when you push water in, the vacuum fights you and can spray water onto the powder too forcefully.

The trick: draw some air into an empty syringe (roughly the same volume of water you plan to add). Insert the needle into the peptide vial and slowly push the air in. This equalises the pressure so the water flows in smoothly when you add it.

Step 4: Draw up your bacteriostatic water.

Using a clean syringe, draw up the desired amount of BAC water. How much you add depends on the concentration you want. We'll cover the maths in the dosage calculator section below, but 2ml is the most common amount for a 5mg peptide vial. Pull the plunger back slowly to avoid air bubbles. If you do get bubbles, flick the syringe gently and push them out before proceeding.

Step 5: Add water slowly down the SIDE of the vial.

This is the most important step and where most people go wrong. Insert the needle into the peptide vial and angle it so the tip touches the inside glass wall. Push the plunger very slowly, letting the water trickle down the side and pool at the bottom.

Do NOT squirt water directly onto the powder. Direct force can damage the peptide bonds and reduce potency. Let gravity do the work. This should take at least 30 seconds for 2ml. Patience pays off.

Step 6: Gently swirl. NEVER shake.

Once all the water is in, remove the needle and gently tilt and roll the vial between your fingers. Think swirling a glass of wine, not shaking a cocktail. Some peptides dissolve in seconds, others take a few minutes.

Shaking creates foam and the mechanical agitation can denature the peptide chains. If the powder isn't dissolving after gentle swirling, put the vial in the fridge for 30 minutes and try again. Sometimes it just needs time.

Step 7: Wait for complete dissolution.

Give the solution a few minutes to fully dissolve. You can put it back in the fridge if you like. Most peptides will be completely dissolved within 5-10 minutes.

Step 8: Check clarity.

Hold the vial up to a light source. The solution should be completely clear and colourless. If it's cloudy, has visible particles, or has a colour to it, something's gone wrong. A slightly hazy solution might clear up with more gentle swirling, but if particles remain after 30 minutes, the peptide may be damaged or contaminated. Don't use it.

Common Reconstitution Mistakes to Avoid

Watch out for these:

• Squirting water directly onto the powder - Damages peptide structure. Always aim down the side of the vial wall.
• Shaking the vial - Causes frothing and denaturation. Gentle swirl only.
• Using sterile water instead of bacteriostatic water - No preservative means bacterial growth in multi-dose vials.
• Not equalising pressure - Leads to uncontrolled water flow that blasts the powder.
• Reusing syringes - Each syringe should be used once. Reusing dulls the needle (causing more pain) and introduces bacteria.
• Forgetting to clean the stopper - The rubber stopper isn't sterile out of the box. Always swab with alcohol.
• Adding too little water - Makes the solution overly concentrated and harder to measure small doses accurately. Using 2ml for a 5mg vial is the sweet spot for most peptides.

Peptide Dosage Calculator

This is where most people get confused, and honestly, the maths isn't hard once you understand the formula. Let's break it down properly.

When you reconstitute a peptide, you're creating a solution with a specific concentration. That concentration tells you how much peptide is in each millilitre (or each "unit" on your insulin syringe).

The Formula

Concentration = Total Peptide (mg) / Volume of BAC Water (ml)

That's it. That's the whole thing.

So if you have a 5mg vial and you add 2ml of bacteriostatic water:

5mg / 2ml = 2.5mg per ml = 2,500mcg per ml

An insulin syringe holds 1ml and has 100 unit markings. Each "unit" equals 1/100th of a millilitre. So at 2,500mcg per ml, each unit contains:

2,500mcg / 100 units = 25mcg per unit

To work out your draw volume: Units to Draw = Desired Dose (mcg) / mcg per Unit

Lets say you want 250mcg of BPC-157. At 25mcg per unit: 250 / 25 = 10 units on the syringe. Simple.

Quick Reference Dosage Table

We've done the maths for the most popular peptides we stock. This table assumes you're using the standard reconstitution volumes we recomend:

A couple of notes on this table. These are common research doses referenced in published literature. Your specific research protocol may differ. Always refer to the relevant studies for your particular application.

Also notice that GHK-Cu and NAD+ use different reconstitution volumes because the vial sizes are much larger. You need to adjust the BAC water volume so the concentration makes sense for practical measuring with an insulin syringe.

BPC-157 Dosage Calculator

BPC-157 is probably our most popular peptide, so let's work through this one in detail. Its also the one we get the most questions about when it comes to dosing.

A standard BPC-157 vial contains 5mg of lyophilised peptide. The most commonly referenced research dose in the literature is 250mcg, typically administered once or twice daily.

Standard reconstitution:

5mg vial + 2ml BAC water = 2,500mcg/ml = 25mcg per unit

For a 250mcg dose: draw to the 10 unit mark on your insulin syringe.

At 250mcg once daily, a single 5mg vial gives you 20 doses, so roughly three weeks of use. At 250mcg twice daily, the same vial lasts about 10 days.

What if you want a different concentration?

Some researchers add just 1ml for a more concentrated solution: 5mg / 1ml = 5,000mcg/ml = 50mcg per unit. For 250mcg you'd draw 5 units. Smaller volumes, but less precision since each unit is a bigger jump in dose.

Add more water (say 2.5ml) and you get 2,000mcg/ml = 20mcg per unit. For 250mcg you'd draw 12.5 units. More precise, but the vial runs out faster.

We recommend sticking with 2ml for a 5mg BPC-157 vial. Best balance of precision and practicality.

BPC-157 dosing frequency in research:

• Standard protocol: 250mcg once daily
• Enhanced protocol: 250mcg twice daily (morning and evening)
• Localised application: injection near the area of interest where possible
• Duration: most studies run 2-4 weeks

GHK-Cu Peptide Dosage

GHK-Cu (copper peptide) is a bit different from other peptides because the vial size is much larger at 50mg. This means you need to think about reconstitution differently.

Standard reconstitution:

50mg vial + 2ml BAC water = 25mg/ml = 250mcg per unit

For the commonly referenced research dose of 1mg: draw to the 4 unit mark.

At 1mg daily, a 50mg vial gives you 50 doses. That's nearly two months from a single vial, which makes GHK-Cu one of the more economical peptides to work with.

You could add 5ml instead to get 10mg/ml (100mcg per unit), drawing 10 units for a 1mg dose. That's fine if you need more precision. But 2ml keeps injection volumes small. If your protocol calls for doses under 1mg, more BAC water gives finer control over measurment.

GHK-Cu research dosing notes:

• Common dose range: 0.5mg to 2mg daily
• Most referenced dose: 1mg daily
• Often used alongside BPC-157 in research protocols
• Duration in studies: typically 4-8 weeks
• Can be administered subcutaneously or topically (different preparations)

For subcutaneous research applications, GHK-Cu is frequently injected near the area of interest, similar to BPC-157. The copper tripeptide has been extensively studied for its role in tissue remodelling and repair signalling.

Custom Dosage Calculations

For any peptide not listed in the table, you can work out the dosing yourself. Here's the process:

1. Check your vial size (it'll be on the label, in milligrams).
2. Decide how much BAC water to add. For vials up to 10mg, 2ml is usually ideal. For larger vials (50mg+), you might want 2-5ml depending on dose size.
3. Divide the vial size by the water volume to get your concentration in mg/ml.
4. Convert to mcg/ml if needed (multiply by 1,000).
5. Divide by 100 to get mcg per unit on the syringe.
6. Divide your desired dose by the mcg-per-unit figure to get your draw volume.

Write this number down and stick it to the vial with a small label. You'll thank yourself later instead of recalculating every time.

How to Inject Peptides: Subcutaneous Injection Guide

Most research peptides are administered via subcutaneous (subQ) injection. This means the needle goes into the fatty tissue just beneath the skin, not into muscle. It's the same method used for insulin, and millions of people do it daily worldwide. Its straightforward once you know what your doing.

Important note: Selank and Semax are exceptions. These peptides are typically administered intranasally (as a nasal spray) rather than by injection. If you've purchased these, you'll want a nasal spray bottle rather than syringes. The reconstitution process is the same, but administration is different.

Injection Site Rotation

You should rotate between multiple injection sites to avoid irritation, bruising, or lipodystrophy (changes to the fat tissue from repeated injections in one spot).

The three main subcutaneous injection sites are:

• Abdomen - The area around your belly button, staying at least 5cm away from the navel itself. This is the most common site and generally the easiest for self-administration. Theres plenty of subcutaneous fat here for most people.
• Thigh - The front or outer side of the upper thigh. Useful if you're rotating away from the abdomen. Pinch a good fold of skin before injecting.
• Upper arm - The back or outer area of the upper arm. This one can be tricky to do yourself, but some people prefer it. You might need someone to help.

For peptides like BPC-157 and GHK-Cu that are being researched for localised effects, injecting as close to the area of interest as possible is common practice in research settings. For example, if researching knee joint repair, the injection would typically be administered in the subcutaneous tissue near the knee.

Injection Technique

Here's the step-by-step process:

1. Prepare your dose. Draw the correct number of units into a fresh insulin syringe. Tap out any air bubbles and push the plunger slightly until a tiny droplet appears at the needle tip. This confirms all air is expelled.

2. Clean the injection site. Swab the area with an alcohol wipe using a circular motion, working outward from the centre. Let it dry completely. Injecting through wet alcohol stings.

3. Pinch the skin. Using your non-dominant hand, pinch a fold of skin between your thumb and forefinger. You want a good inch or so of pinched skin. This lifts the subcutaneous fat away from the muscle beneath.

4. Insert the needle. Insert the needle at a 45 to 90 degree angle. For most people, 90 degrees (straight in) works fine with insulin needles because they're short (8mm or 12.7mm). If you're very lean, use 45 degrees to stay in the subcutaneous layer and avoid muscle.

5. Inject slowly. Push the plunger down steadily over about 5-10 seconds. There's no rush. Slower injection means less discomfort and better absorption.

6. Wait briefly, then withdraw. After the plunger is fully depressed, wait 5 seconds before pulling the needle out. This prevents any solution leaking back out through the needle track.

7. Don't rub the site. You might see a tiny drop of blood or a small bump where the liquid is sitting under the skin. That's completely normal. Don't massage or rub the area. A gentle press with a clean cotton ball or alcohol swab is fine if there's a blood drop.

Post-Injection Care and Sharps Disposal

You might notice a small welt or redness at the injection site. This usually disappears within an hour. Some peptides cause a mild stinging or warming sensation, which is also normal. If you notice significant swelling, persistent redness, or any signs of infection (pus, increasing pain, red streaks), seek medical attention.

Every used syringe goes straight into your sharps container. Never recap needles and never put them in regular household waste. When the bin is three-quarters full, take it to your local pharmacy or council collection point. Most UK pharmacies accept sharps bins free of charge.

How to Store Peptides

Proper storage is the difference between peptides that work and expensive dust. Peptides are delicate molecules that degrade when exposed to heat, light, moisture, and bacterial contamination. Here's exactly how to store them at every stage.

Storage Conditions Reference Table

The key takeaway from this table: keep your unreconstituted peptides in the fridge, and once you've mixed them, use them within a few weeks. Simples.

Storing Lyophilised (Powder) Peptides

When your peptides arrive, they should go straight in the fridge at 2-8 degrees Celsius. This is the standard temperature range for a household refrigerator. Keep them in the back of the fridge where the temperature is most stable, not in the door where it fluctuates every time you open it.

For long-term storage of peptides you won't use for several months, a freezer at -20C extends shelf life significantly. Most domestic freezers run at about -18C which is close enough. Just be aware that repeated freeze-thaw cycles can damage peptides, so only freeze vials you plan to thaw once.

Lyophilised peptides are the most stable form. The freeze-drying process removes virtually all water, which is the primary driver of degradation. As long as you keep them sealed, dry, and cool, they'll last a very long time.

Storing Reconstituted Peptides

Once you add bacteriostatic water, the clock starts ticking. Reconstituted peptides should be kept refrigerated at all times and used within 2-4 weeks for optimal potency. The benzyl alcohol in BAC water helps prevent bacterial growth, but it doesn't stop peptide degradation entirely.

Never leave a reconstituted vial sitting out at room temperature. Even a few hours of warmth accelerates breakdown. If you accidentally leave one out overnight, it's probaly still usable but the potency may be reduced. Get it back in the fridge immediately and use it up quickly.

Aliquoting for Long-Term Use

If you've bought peptides in bulk, consider aliquoting. This means reconstituting the peptide and dividing the solution into smaller portions in separate sterile vials. You only thaw one small portion at a time, keeping the rest frozen. Each aliquot goes through just one freeze-thaw cycle.

To aliquot properly:

• Reconstitute the full vial as normal
• Using sterile technique, draw out measured portions into separate sterile vials
• Label each vial with the peptide name, concentration, date, and volume
• Freeze the aliquots you won't use immediately
• Keep one in the fridge for current use

Light Sensitivity

Some peptides are photosensitive, meaning light triggers degradation. Keep all peptide vials away from direct light. Store them in the box they came in, or wrap them in aluminium foil. The fridge is mostly dark anyway, but its good practice to add that extra protection. Copper peptides like GHK-Cu are particularly worth shielding, as the copper ion can catalyse photo-oxidation.

Signs of Degradation

How do you know if a peptide has gone bad? Here are the warning signs:

• Cloudiness or particles in a reconstituted solution - A fresh solution should be crystal clear. Any haziness or floating specks suggest contamination or aggregation.
• Colour change - Most peptide solutions are colourless. Yellowing or any other discolouration indicates oxidation or degradation.
• Unusual smell - Reconstituted peptides should have little to no odour beyond a faint alcohol scent from the BAC water. Anything off-putting means contamination.
• Clumping of lyophilised powder - If your powder has gone from a fluffy, dry cake to a sticky or clumped mass, moisture has got in. The peptide may still be partially viable but potency will be reduced.
• Difficulty dissolving - If a peptide that normally dissolves easily suddenly won't go into solution, degradation is likely.

When in doubt, don't use it. A degraded peptide at best won't work and at worst could contain bacterial contamination. Its not worth the risk to save a few quid.

Frequently Asked Questions

How much bacteriostatic water should I add to my peptide vial?

For most 5mg vials, 2ml of BAC water is standard. This gives you 2,500mcg/ml, which makes dosing calculations straightforward. For larger vials like 50mg GHK-Cu, 2ml still works but you can add up to 5ml for easier measurement. The amount of water doesn't change the total peptide, it only changes concentration.

Can I use sterile water instead of bacteriostatic water?

Only if you'll use the entire vial in one session. Sterile water has no preservative, so bacteria multiply freely once the stopper is punctured. Since most people draw multiple doses over weeks, bacteriostatic water is essential.

How long do reconstituted peptides last?

Refrigerated at 2-8 degrees, most reconstituted peptides stay stable for 2-4 weeks. Frozen, they can last 3-6 months, but avoid repeated freeze-thaw cycles.

What does "units" mean on an insulin syringe?

An insulin syringe holds 1ml divided into 100 units. Each unit is 0.01ml. When we say "draw 10 units," we mean pull the plunger to the 10 line. These units have nothing to do with International Units (IU) used for other compounds. They're purely volume markings.

Do I need to inject peptides at the same time every day?

Consistency helps but exact timing isn't critical. Pick a regular time like morning or evening so you don't forget. Not missing doses matters more than hitting an exact time.

Can I mix two peptides in the same syringe?

Some researchers combine compatible peptides in one injection. BPC-157 and TB-500 are commonly paired, for instance. But not all peptides play nicely together, and mixing can sometimes cause aggregation. Unless a specific combination has been validated in research, its safer to inject them separately.

What if I see a small bubble in the syringe?

A tiny air bubble in a subcutaneous injection is harmless. But bubbles take up space and affect dose accuracy. Hold the syringe needle-up, flick gently to move the bubble to the top, then push the plunger until a small drop appears at the tip.

Why does my reconstituted peptide look cloudy?

You may have added water too forcefully onto the powder. Pop it in the fridge for 15-20 minutes and gently swirl occasionally. It often clears up on its own. If it stays cloudy after 30 minutes, the peptide may be degraded. Dont use a solution that won't clear.

My peptide vial arrived at room temperature. Is it still good?

Almost certainly yes. Lyophilised peptides are reasonably stable at room temp for short periods. A day or two in transit is fine. The freeze-dried form is designed to handle shipping. Just get them in the fridge as soon as you can after delivery.

Is it normal for the injection site to be itchy or red afterwards?

Mild redness, a small bump, or slight itching is quite common and usually resolves within an hour. It's a normal histamine response. If redness spreads significantly, becomes painful, or doesn't resolve within 24 hours, consult a healthcare professional.

A Note on Safety and Legality

Peptides are legal to buy and possess in the UK for research purposes. They are not licensed medicines, and we're not medical professionals. Nothing in this guide constitutes medical advice. If you have any health concerns or are considering using peptides alongside other medications, speak to your GP or a qualified healthcare professional.

All products are sold for research purposes only.

Always source your peptides from reputable suppliers who provide third-party purity testing. At UK Peptide Shop, every batch comes with a certificate of analysis confirming purity, typically 98%+ as verified by HPLC testing. A cheap vial from an unknown source could contain impurities, underdosed product, or the wrong compound entirely.

Practice proper sterile technique every single time. Clean surfaces, alcohol swabs on stoppers and skin, fresh syringes for every use, and proper sharps disposal. These aren't suggestions, they're essentials. If this is your first time, take it slow, follow the steps methodically, and don't rush. After your first vial you'll realise how straightforward it all is.