What is my peptide dose in units?
Enter the milligrams in the vial and the water you add to get the concentration, then type your prescribed dose to see the mL and the units to draw on a U-100, U-50, or U-40 syringe. The calculator does the arithmetic only and suggests no doses. For information only. This is not medical advice or a diagnosis. Do not use it to make treatment decisions without a clinician. No licensed clinician has reviewed this page. Many peptides sold online are not approved medicines.
- Concentration (mg/mL)
- 2.5
The mixed vial holds 2.5 mg per mL, which is 25 mcg per syringe unit.
- Per syringe unit (mcg)
- 25
Concentration (mg/mL): 2.5. The mixed vial holds 2.5 mg per mL, which is 25 mcg per syringe unit.
This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use
How to calculate
Does reconstitution arithmetic: the concentration after adding water to a vial, and the mL and syringe units (U-100, U-50, or U-40) for a dose you type. It has no drug presets and suggests no doses.
Example with the default inputs (Amount in the vial (mg) 5, Water added (mL) 2, Dose unit mcg, Syringe U-100): The mixed vial holds 2.5 mg per mL, which is 25 mcg per syringe unit.
Method: Concentration (mg/mL) = vial mg ÷ water mL. Volume (mL) = dose (mg) ÷ concentration. Syringe units = volume × units per mL (100, 50, or 40).
- The powder dissolves fully and adds no volume, the usual assumption for small peptide vials.
- The dose is the one you were prescribed; the calculator has no drug list and suggests no doses.
- Values are rounded for display, halves up; full doses round down.
Worked examples
Each example is checked against the calculator on every build.
- Amount in the vial (mg) 5, Water added (mL) 2, Dose 250, Dose unit mcg, Syringe U-100 gives Concentration (mg/mL) 2.5, Per syringe unit (mcg) 25, Volume for the dose (mL) 0.1, Syringe units for the dose 10, Full doses in the vial 20.Source: × 100 units/mL (ISO 8537 U-100) = 10 units
- Amount in the vial (mg) 10, Water added (mL) 3, Dose 500, Dose unit mcg, Syringe U-100 gives Concentration (mg/mL) 3.333, Per syringe unit (mcg) 33.33, Volume for the dose (mL) 0.15, Syringe units for the dose 15, Full doses in the vial 20.
- Amount in the vial (mg) 5, Water added (mL) 1, Dose 1, Dose unit mg, Syringe U-40 gives Concentration (mg/mL) 5, Per syringe unit (mcg) 125, Volume for the dose (mL) 0.2, Syringe units for the dose 8, Full doses in the vial 5.
- Amount in the vial (mg) 2, Water added (mL) 1.5, Dose 0.25, Dose unit mg, Syringe U-100 gives Concentration (mg/mL) 1.333, Volume for the dose (mL) 0.188, Syringe units for the dose 18.8, Full doses in the vial 8.
- Amount in the vial (mg) 5, Water added (mL) 2, Dose unit mcg, Syringe U-50 gives Concentration (mg/mL) 2.5, Per syringe unit (mcg) 50.
Medical disclaimer
This calculator is for information and education only. It is not medical advice, and its result is not a diagnosis. Do not use it to start, stop, or change a treatment without a clinician who knows your health history. No licensed clinician has reviewed this page. This site's editors checked the formulas and worked examples against published sources. If you think you have a medical emergency, call your local emergency number.
When this does not apply. This page is reconstitution arithmetic for a dose that a prescriber has given you. It does not say whether a product is safe, legal, or approved, and it does not apply to pre-mixed products, whose label gives the strength.
Many peptides sold online are not approved medicines. This page does reconstitution arithmetic only: it has no drug presets and suggests no doses.
How the numbers are worked out
- Concentration (mg/mL) = vial mg ÷ water mL. In mcg/mL, multiply by 1,000.
- Micrograms per syringe unit = concentration × 1,000 ÷ units per mL (U-100: 100, U-50: 50, U-40: 40).
- Volume for the dose (mL) = dose (mg) × water mL ÷ vial mg. A dose in mcg is divided by 1,000 first.
- Syringe units = volume × units per mL.
- Full doses in the vial = vial mg ÷ dose mg, rounded down to a whole number (a result within 1e-9 of the next whole number counts as that number).
The concentration is shown to 3 decimals, micrograms per unit to 2, the volume to 3, and syringe units to 1, each rounded halves up from the unrounded value, read from the decimal value (within 1e-9, relative, of a half counts as the half). The powder is assumed to add no volume.
Inputs the calculator accepts
Vial 0.01 to 1,000 mg; water 0.1 to 100 mL; dose 0.001 to 1,000,000 in mcg or mg. The dose is optional; with no dose, the page shows the concentration and micrograms per unit only.
Worked examples by hand
5 mg vial, 2 mL water, 250 mcg dose, U-100. 5 ÷ 2 = 2.500 mg/mL; 2,500 ÷ 100 = 25.00 mcg per unit. 0.25 mg × 2 ÷ 5 = 0.100 mL = 10.0 units. 5 ÷ 0.25 = 20 doses.
10 mg vial, 3 mL water, 500 mcg dose, U-100. 10 ÷ 3 = 3.3333 = 3.333 mg/mL; 33.33 mcg per unit. 0.5 × 3 ÷ 10 = 0.150 mL = 15.0 units. 20 doses.
5 mg vial, 1 mL water, 1 mg dose, U-40. 5.000 mg/mL; 5,000 ÷ 40 = 125.00 mcg per unit. 1 ÷ 5 = 0.200 mL × 40 = 8.0 units. 5 doses.
2 mg vial, 1.5 mL water, 0.25 mg dose, U-100. 2 ÷ 1.5 = 1.333 mg/mL. 0.25 × 1.5 ÷ 2 = 0.1875, shown 0.188 mL; × 100 = 18.75, shown 18.8 units. 2 ÷ 0.25 = 8 doses.
5 mg vial, 2 mL water, U-50, no dose. 2.500 mg/mL; 2,500 ÷ 50 = 50.00 mcg per unit.
Other questions people ask
How do I calculate peptide reconstitution?
Divide the milligrams in the vial by the milliliters of water you add. A 5 mg vial mixed with 2 mL of water holds 5 ÷ 2 = 2.5 mg per mL, which is 2,500 mcg per mL.
How many units on an insulin syringe is my dose?
First find the volume: dose ÷ concentration. Then multiply by the syringe scale. A U-100 syringe has 100 units in 1 mL, so each unit is 0.01 mL. For a 250 mcg dose from a 2,500 mcg/mL vial: 250 ÷ 2,500 = 0.1 mL = 10 units on a U-100 syringe.
What is the difference between U-100, U-50, and U-40 syringes?
The number is how many marked units fit in 1 mL. On a U-100 syringe one unit is 0.01 mL; on a U-40 syringe one unit is 0.025 mL. The same dose is a different number of units on each scale, so use the scale that matches your syringe.
Does the calculator tell me how much peptide to take?
No. It has no drug list and no suggested doses; it only turns a dose you were prescribed into mL and syringe units. Many peptides sold online are research chemicals, not approved medicines, and the US Food and Drug Administration has warned that some bulk peptides may present significant safety risks.
Does the powder change the volume?
For the small amounts in peptide vials the powder adds almost no volume, so the calculator treats the volume as the water you added. This is the usual assumption.