Peak
Research & Tracking
Peptide Dosage Calculator
Peptide dosing involves three numbers that people routinely mix up: the strength printed on the vial in milligrams, the dose discussed in micrograms, and the units marked on an insulin syringe. Getting from one to the other is simple arithmetic, but it's arithmetic done at arm's length with a fine needle, which is exactly when a decimal point goes missing.
This calculator does the conversion and shows the answer where it matters — as a mark on a syringe — along with how many doses the vial will give you.
The three calculations
concentration (mcg/mL) = vial strength (mcg) ÷ water added (mL)
draw volume (mL) = dose (mcg) ÷ concentration (mcg/mL)
units on a 100-unit syringe = draw volume (mL) × 100
Worked example: a 10 mg vial is 10,000 mcg. Reconstituted with 2 mL, that's 5,000 mcg/mL. A 500 mcg dose is 0.1 mL, which is 10 units — and the vial holds 20 of those doses.
Visual syringe readout
The answer is drawn on a 100-unit or 1 mL syringe, so you're matching a picture rather than converting in your head.
Water volume suggestions
The tool proposes the reconstitution volume that puts your dose on a clean, whole-number mark.
Doses per vial
See how long a vial lasts at your dose before you mix it, so you can plan reorders.
Preset compounds
Common peptides come with typical vial strengths pre-filled, or enter your own numbers.
For the full step-by-step version with mixing technique and storage notes, see the peptide reconstitution guide. To keep a record of what you actually injected, the peptide tracking app logs each dose against the vial it came from.
Peptide dosage calculation questions
What is the formula for calculating a peptide dose?
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Concentration in mcg per mL equals the vial strength in micrograms divided by the millilitres of water you added. The volume to draw equals your dose in micrograms divided by that concentration, and units on a 100-unit insulin syringe equal that volume multiplied by 100. A 10 mg vial with 2 mL of water is 5,000 mcg/mL, so a 500 mcg dose is 0.1 mL — 10 units.
How do I convert mg to mcg for peptide dosing?
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One milligram is 1,000 micrograms. Most vials are labelled in mg while doses are discussed in mcg, which is where the worst errors happen: a 5 mg vial holds 5,000 mcg, so a 250 mcg dose is one twentieth of the vial. The calculator does the conversion for you and shows the result as units on a syringe rather than a decimal you have to eyeball.
Why do the units to draw change when I change the water volume?
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Because you're changing concentration, not quantity. The vial always holds the same amount of peptide; more water means each unit contains less of it, so you draw more units for the same dose. Pick the water volume that lands your usual dose on a round, easy-to-read mark.
What syringe should I use for microgram doses?
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A 100-unit (1 mL) insulin syringe with a fine 29-31 gauge, 8 mm needle. Its graduations are small enough to read a 10-unit draw confidently. A 3 mL syringe is far too coarse for microgram dosing.
How many doses will one vial give me?
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Doses per vial equals total vial strength divided by dose per injection, and it does not depend on how much water you added. A 10 mg vial at 500 mcg per dose is 20 doses whether you reconstituted with 1 mL or 3 mL.
Provided for informational and research purposes only, and not medical advice. Always verify calculations independently and use sterile technique.