Peptide Dosage Calculator
This free calculator helps you reconstitute (mix) a peptide correctly and find the right draw amount for your U100 insulin syringe - concentration, marks (IU), millilitres to draw and doses per vial. Pick the peptide, vial size and your desired dose; it computes the rest live and suggests a suitable amount of BAC water. The full procedure is in the step-by-step reconstitution guide. A calculation aid only, no sign-up - nothing is stored.
Free registered users also get the Dosage Manager: it stores the mixes and reconstitutions you create, calculates the doses from them, lets you log your injections and tracks along. You always keep the full picture!
- Concentration- mg/ml
- Draw up- ml
- Insulin units (IU)- IE
- Doses per vial-
Note: a calculation aid only, not medical advice and not a dosing recommendation. When in doubt, consult a physician.
Frequently asked questions
What is a peptide calculator?
A peptide calculator works out the exact liquid volume you need to draw up to inject a given dose. Because peptides ship as a powder (lyophilisate), you first mix them with bacteriostatic water (BAC). The calculator removes the guesswork from converting milligrams of powder into millilitres on the syringe.
Why is the calculation so important?
Peptides are highly potent, so a wrong dose can reduce effectiveness or increase side effects. The calculation matters because tiny volume differences translate into large dose differences. The calculator removes the risk of human arithmetic errors and keeps the maths reproducible.
What is BAC water?
Bacteriostatic water contains about 0.9 % benzyl alcohol, which inhibits bacterial growth in an opened vial. It matters because it lets you store a reconstituted vial for several uses. Never use tap water or boiled water for injections.
How do I calculate the right peptide dose?
Volume to draw up (ml) = (target dose ÷ vial strength) × BAC water added. Example: 250 mcg target, 5 mg (5000 mcg) vial, 2 ml water → (250 ÷ 5000) × 2 = 0.1 ml. On a U100 syringe, 0.1 ml = 10 units (IU). This formula always converts your target dose into a volume you can read on the syringe.
Units (IU) or ml - what counts on the syringe (U-100, U-40, 50-unit syringe)?
What matters is the syringe's scale (U-100 or U-40), not its size. On the common U-100 insulin syringe: 100 units (IU) = 1 ml. So 50 IU = 0.5 ml, 20 IU = 0.2 ml, 10 IU = 0.1 ml.
Don't confuse the scale with the barrel size: U-100 syringes come in different capacities. The most common for peptides is the "50-unit" (0.5 ml) - it holds at most 50 IU = 0.5 ml. A full millilitre does not fit; 1 ml equals 100 IU, i.e. a full 1-ml/100-unit syringe. Common U-100 sizes:
- 0.3 ml = 30 IU (U-100)
- 0.5 ml = 50 IU (U-100) - the most common
- 1.0 ml = 100 IU (U-100)
Less common is the U-40 scale (40 IU = 1 ml, i.e. 10 IU = 0.25 ml), typical for some veterinary insulins. Always read the "U-100" or "U-40" marking on the syringe and convert accordingly. Our dosage calculator gives you the right volume.
How much BAC water should I use?
Choose a practical amount: not too little (dissolves poorly, stings) and not too much (injection volume too large). For standard vials (5–10 mg), 2–3 ml is a proven default. More water lowers the concentration, so you draw up a larger volume for the same dose.
Can I change the concentration?
Yes. More water lowers the concentration, so you draw up a larger volume for the same dose; less water does the opposite. Adjust the calculation accordingly - the calculator does this automatically once you change the water volume.