Peptide Calculator

How the maths works

The calculator does three small conversions in sequence. None of it is complicated — but doing it on the back of an envelope every time is where mistakes creep in.

Concentration (mg/mL). The amount of peptide in your vial divided by the amount of bacteriostatic water you added. A 10mg vial reconstituted with 2mL of BAC water gives 5 mg/mL.

Draw volume (mL). Your target amount divided by the concentration. If your concentration is 5 mg/mL and you want 2mg per draw, that's 0.40 mL.

Syringe units. A standard U-100 insulin syringe has 100 unit marks per 1 mL — so 0.40 mL is 40 units. The 0.5 mL and 0.3 mL syringes use the same scale, just with a smaller barrel.

Reconstitution best practice

The calculator handles the maths. Sterile technique is on you. A short checklist:

• Bring everything to room temperature first. Lyophilised peptides are hygroscopic — opening a cold vial lets moisture condense inside, which degrades the powder before you've even added water.
• Swab the rubber stopper on both the BAC water vial and the peptide vial with an alcohol wipe before each puncture.
• Add water slowly, down the side of the vial. Don't blast it onto the powder. Tilt the vial at a slight angle and let the water run down the glass.
• Swirl gently. Do not shake. Shaking foams the solution and can damage the peptide structure. A slow swirl until the powder dissolves is what you want.
• Store reconstituted vials at 2–8°C (a normal fridge). Most reconstituted peptides remain stable for around 28 days at fridge temperature. For longer-term storage of unreconstituted powder, –20°C or below.
• Avoid repeated freeze/thaw cycles on reconstituted solution. Each cycle compromises peptide integrity.

FAQ

What does "U-100" mean on a syringe?

U-100 is a scale, not a size. It means there are 100 unit marks per 1 mL of barrel volume. A 1 mL U-100 syringe has 100 unit marks; a 0.5 mL U-100 syringe has 50 marks across its smaller barrel; a 0.3 mL U-100 syringe has 30 marks. The unit-to-mL conversion is the same on all three: 1 unit = 0.01 mL.

Which syringe size should I use?

Generally, the smallest syringe whose barrel comfortably fits your draw. A smaller barrel spreads the unit marks further apart, making it easier to read accurately. If your draw is 10 units, a 0.3 mL barrel will read more clearly than a 1 mL barrel — but if your draw exceeds 30 units you can't use a 0.3 mL syringe at all. The calculator flags this when it happens.

How much BAC water should I add?

There's no single right answer — it's a tradeoff. Less BAC water gives a more concentrated solution, meaning smaller, more precise draws but tighter margin for measurement error. More BAC water gives larger draw volumes that are easier to read on the syringe but use up syringe capacity faster. Most laboratory protocols land between 1mL and 3mL for typical 5–10mg vials.

How long does a reconstituted vial last?

Most peptides remain stable for around 28 days at 2–8°C (fridge). This is a general guideline — specific peptides have specific stability profiles, and storage discipline matters more than the calendar. Keep the vial refrigerated, minimise time at room temperature, and don't freeze a reconstituted solution.

Can I use sterile water or saline instead of bacteriostatic water?

Bacteriostatic water contains 0.9% benzyl alcohol as a preservative — it's the preservative that lets you draw from the same vial multiple times over weeks without bacterial growth. Sterile water without preservative is single-use; once you've punctured the stopper, the contents should be used straight away. Saline is fine for some peptides but not all. For most laboratory peptide work, BAC water is the default solvent.

What if my peptide isn't in the dropdown?

Select "Custom / not listed" and type the mg in the vial directly. The calculator works the same way — the dropdown is just a convenience for products we stock.

Why is the answer changing as I type?

The calculator updates live — there's no submit button. Every change to vial size, BAC water, or target amount recalculates instantly. If a value isn't valid (zero, negative, or empty), the results show "—" until you finish typing.

Are these dosing recommendations?

No. The calculator performs mathematical conversions on values you supply. We do not recommend doses, suggest protocols, or provide medical guidance. All Optic Labs products are supplied for laboratory and research use only and are not for human consumption. Verify all calculations against your own protocols before use.

Optic Labs supplies research peptides for laboratory and research use only. Products are not medicines, are not approved by the TGA for human use, and are not for human consumption. The reconstitution calculator is a mathematical tool that performs unit conversions on user-supplied values. It does not constitute medical, dosing, or therapeutic advice.