Peptide Calculator

Why Precise Peptide Dosing Matters

Peptide research demands accuracy at every step, and nowhere is this more critical than at the point of reconstitution and dose measurement. A seemingly minor miscalculation — say, adding twice the intended BAC water volume — halves your peptide concentration and means every subsequent injection delivers half the intended dose. You may spend weeks running a protocol with no results, never realizing the issue was in the math before the first injection.

The challenge is compounded by the unit systems involved. Lyophilized peptides are sold by weight in milligrams. Doses are measured in micrograms. Injection volumes are measured in milliliters. And insulin syringes — the standard tool for subcutaneous peptide injections — are scaled in Units (IU), not milliliters. Each conversion introduces another opportunity for error.

Our peptide calculator collapses all of these conversions into a single workflow. Enter your peptide amount, BAC water volume, target dose, and syringe size — and receive the exact concentration, injection volume in milliliters, and the corresponding IU marking on your syringe. The entire calculation chain happens in one place, with no manual steps to introduce error.

Beyond accuracy, a calculator enforces consistency. When you run the same protocol over 30 or 60 days, consistency matters as much as precision. Storing your settings as a saved protocol means every injection uses the same parameters, regardless of how much time has passed since you set things up.

How the Peptide Calculator Works

The calculator takes four inputs and produces three outputs. Here is what each input controls and why it matters:

Inputs

1. Peptide amount (mg): The total amount of lyophilized peptide in your vial. Standard research vials range from 2 mg to 10 mg. This value is typically printed on the vial label. If you are using a partial vial, enter only the remaining amount.
2. BAC water volume (ml): How much bacteriostatic water you add to the vial during reconstitution. This single value determines your final concentration. Adding 1 ml to a 5 mg vial gives you a 5,000 mcg/ml solution. Adding 2 ml gives you 2,500 mcg/ml.
3. Target dose (mcg): Your desired dose per injection in micrograms. This is peptide-specific and should be determined based on the protocol you are following. For reference, the BPC-157 calculator shows typical dose ranges alongside the calculation.
4. Syringe size: The capacity of your insulin syringe — 0.3 ml, 0.5 ml, or 1.0 ml. This determines how IU markings on the syringe correspond to actual volumes.

Outputs

• Concentration (mcg/ml): The peptide density of your reconstituted solution. Knowing this value lets you cross-check the other outputs manually if you ever need to.
• Volume per dose (ml): The exact milliliter volume to draw for each injection.
• IU marking: The unit marking on your U-100 insulin syringe that corresponds to your target dose. This is what you actually read off the syringe when drawing up.

Specific peptide calculators — like the TB-500 calculator and the Hexarelin calculator — come with pre-filled standard values and peptide-specific context. They are a good starting point when you are working with a peptide for the first time.

BAC Water: Bacteriostatic Water Explained

Bacteriostatic water — abbreviated BAC water — is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a preservative, inhibiting the growth of bacteria, yeast, and mold. This preservative property is the entire reason BAC water is the standard solvent for reconstituting peptides intended for multi-use vials.

Every time you insert a needle through a rubber septum to draw a dose, you introduce a small risk of contamination. With plain sterile water, that risk accumulates rapidly over repeated draws. Benzyl alcohol dramatically reduces this risk, making it safe to use a single vial for multiple injections over several weeks.

Plain sterile water is sometimes listed as an alternative to BAC water, but it is only appropriate for single-use preparations where the entire vial is used in one injection session. For the extended protocols typical in peptide research — where a single vial might supply 20 to 30 daily injections — BAC water is the correct choice.

One important caveat: the 0.9% benzyl alcohol content makes BAC water inappropriate for intravenous use. For subcutaneous injections, which are standard for peptides, it is well tolerated. If you experience any localized irritation at the injection site that does not resolve, the solvent is one variable worth examining.

Storage for BAC water is straightforward — unopened vials are stable at room temperature for years. Once opened, store at room temperature away from direct light and use within the manufacturer's recommended window, typically 28 days. Do not refrigerate opened BAC water vials, as condensation can compromise the septum seal.

Choosing the Right Insulin Syringe

Insulin syringes are the standard tool for subcutaneous peptide injections. They are sterile, precisely calibrated, and the fine gauge needles minimize injection discomfort and tissue trauma. The most widely used are BD MICRO-FINE+ syringes, available in three sizes that cover essentially every peptide dosing scenario:

• 0.3 ml / 30G: The smallest option, with 30 unit markings at 1 IU intervals. Best suited for very small injection volumes — typically when your calculated dose falls below 0.2 ml. The limited capacity is the constraint; the 1 IU graduation is the same as the 0.5 ml version.
• 0.5 ml / 30G: The most versatile size for peptide work. Fifty 1 IU graduations provide sufficient precision for most dose ranges, and the 0.5 ml capacity handles the majority of standard peptide protocols. If you are buying syringes for the first time, start here.
• 1.0 ml / 33G: Used when injection volumes exceed 0.5 ml, or when stacking multiple peptides in a single injection. The 33G needle is the thinnest of the three — finer than a hair — but the 100-unit scale means each graduation represents the same 0.01 ml. Reading small volumes accurately on a 1 ml syringe requires good lighting and attention.

All three are U-100 syringes. This means 100 units fills exactly 1 ml. The math is constant: 1 IU always equals 0.01 ml, regardless of which peptide or concentration you are working with. The IU marking on the syringe is a volume marker — it tells you how much liquid is in the syringe, not how much peptide. How much peptide is in that volume depends on your concentration, which is exactly what the calculator determines.

For protocols like CJC-1295, where doses typically fall in the 100–300 mcg range, the 0.5 ml syringe is almost always the right choice. For peptides with larger per-dose weights — like TB-500 at 2–5 mg per injection — a 1.0 ml syringe may be necessary depending on your reconstitution volume.

Storing Peptides: Cold Chain and Shelf Life

Lyophilized peptides are more stable than most people expect. The freeze-drying process removes virtually all moisture, which is the primary driver of peptide degradation. Unopened vials stored at refrigerator temperatures (2–8°C) typically remain stable for 12–24 months. Many manufacturers rate their products for even longer periods under ideal conditions.

For long-term storage beyond several months, -20°C is the recommended temperature. A standard freezer compartment works well. The critical rule when freezing: avoid repeated freeze-thaw cycles. Each cycle stresses the peptide molecular structure. If you are freezing a vial for long-term storage, plan to use it completely once thawed. Do not refreeze.

After reconstitution with BAC water, the clock starts. Reconstituted peptide solutions should be stored at 2–8°C (refrigerator, not freezer) and used within 21–30 days. The exact window varies by peptide — BPC-157 tends to be more stable in solution than peptides with disulfide bonds or other reactive features. When in doubt, err toward the shorter end of the range.

Do not freeze reconstituted peptide solutions. The water in the solution forms ice crystals that can physically disrupt peptide structure and cause aggregation. Once a peptide is in solution, refrigerate and use within the recommended window.

Practical storage habits that make a real difference:

• Label every vial immediately upon reconstitution with the date and peptide name. Laboratory tape and a fine marker work well. You will not remember the date three weeks later.
• Protect from light. Many peptides are photosensitive. Store vials in the back of the refrigerator or in a box if your fridge has a light that runs while the door is closed.
• Store upright. Keeping vials vertical ensures the septum seal is never compromised by liquid contact.
• Inspect before each draw. The solution should be clear and colorless. Turbidity, discoloration, or visible particles are signals to discard the vial — these indicate either contamination or significant peptide degradation.

Safe Disposal of Sharps and Vials

Used insulin needles are sharps waste — they cannot go in regular household trash. A needle puncture through a garbage bag is a genuine injury risk to anyone handling the waste downstream. Proper disposal is both a practical and, in most jurisdictions, a legal requirement.

Sharps containers are the solution. These rigid, puncture-resistant plastic containers are specifically designed for used needles, lancets, and other sharps. They are available at pharmacies — often inexpensively or free as part of diabetic supply programs. Fill to the indicated maximum line (usually three-quarters full), then seal.

For disposal, most pharmacies accept sealed sharps containers at no charge. Some municipalities have medical waste drop-off points at health centers or waste management facilities. Check your local pharmacy first — it is typically the most convenient option.

Empty glass vials — both peptide vials and BAC water vials — can generally be rinsed and disposed of in glass recycling. If you are uncertain about local requirements, your pharmacy can advise, and many will accept empty pharmaceutical vials directly.

One non-negotiable rule: never recap a used needle by pointing the cap with your other hand. If you need to cap before disposal, use the one-handed scoop method. Better yet, move the syringe directly from injection to sharps container without recapping at all.

Frequently Asked Questions

What is the difference between mg and mcg in peptide dosing?

Milligrams (mg) is the unit used for the total peptide amount in a vial — for example, "5 mg BPC-157." Micrograms (mcg or µg) is the unit used for individual doses — for example, "250 mcg per injection." One milligram equals 1,000 micrograms. The calculator accepts peptide amounts in mg and target doses in mcg, handling the conversion automatically.

How much BAC water should I use for a 5 mg peptide vial?

The right amount depends on your dose. With 1 ml of BAC water in a 5 mg vial, your concentration is 5,000 mcg/ml. At a 250 mcg dose, you would draw 0.05 ml (5 IU on a U-100 syringe). With 2 ml of BAC water, concentration drops to 2,500 mcg/ml — the same 250 mcg dose now requires 0.1 ml (10 IU), which is easier to measure accurately. Use the peptide calculator to model different BAC water volumes instantly.

Can I mix multiple peptides in one syringe?

In many cases, yes. Compatible peptides — such as BPC-157 and TB-500, which are frequently combined — can be drawn into the same syringe and injected together. The key requirements are pH compatibility and that neither peptide precipitates in the presence of the other. Draw each peptide from its vial separately, combine in the syringe, and inject immediately. Do not prepare mixed syringes in advance for later use.

What does "U-100" mean on an insulin syringe?

U-100 indicates the syringe is calibrated for insulin with a concentration of 100 units per milliliter. The unit scale on the barrel reflects this: 100 IU fills exactly 1 ml, meaning each 1 IU graduation represents 0.01 ml. This relationship is fixed regardless of what you are drawing into the syringe. When the calculator tells you to draw "12 IU," that always means 0.12 ml of your peptide solution.

How long does reconstituted peptide last in the refrigerator?

Most reconstituted peptides stored at 2–8°C remain usable for 21–30 days. Some are more stable than others. Always label vials with the reconstitution date so you know when the window closes. If the solution has developed any turbidity, changed color, or shows particulate matter, discard it regardless of how recently it was reconstituted.

Why is my calculated injection volume very small?

A very small calculated volume — say, 0.02 ml or 2 IU — means your solution concentration is high relative to your dose. This typically happens when you use a small volume of BAC water. Volumes below 0.05 ml (5 IU) can be difficult to measure accurately with a standard insulin syringe. The fix is to increase your BAC water volume, which lowers the concentration and produces a larger, more manageable injection volume for the same dose.

Are there calculators for specific peptides?

Yes. In addition to the general peptide calculator, there are dedicated calculators for individual peptides with pre-filled typical values and peptide-specific context:

• BPC-157 Calculator
• TB-500 Calculator
• Hexarelin Calculator
• CJC-1295 Calculator
• Ipamorelin Calculator
• GHRP-6 Calculator
• GHRP-2 Calculator
• DSIP Calculator
• 5-Amino-1MQ Calculator

More calculators: GHRH, melanocortins, immunity & cognition

The index also includes Sermorelin, Tesamorelin, Melanotan II, Melanotan I, Thymosin Alpha-1, Epithalon, KPV, HGH Fragment 176-191, Semax, N-Acetyl Semax— each with its own article and calculator presets.

Do I need to recalculate every time I inject?

Not if you save your protocol. The calculator includes a Protocols tab where you can save your current settings — peptide, BAC water volume, dose, and syringe — as a named protocol. Load it any time to restore all values instantly. This is particularly useful when running multiple peptides simultaneously or when you want to compare different dosing approaches for the same peptide.

What should I do if my peptide solution looks cloudy?

Discard it. A cloudy or turbid peptide solution indicates either bacterial contamination or peptide aggregation — both of which render the solution unsuitable for use. This can happen if BAC water is added too aggressively (always add it slowly down the side of the vial, never directly onto the lyophilized cake), if the vial was temperature-shocked, or if the solution has aged past its usable window. Reconstitute a fresh vial.