Peptide Pen Dosage
Calculator

How to calculate your peptide dose

1. 1

   Enter your peptide amount (mg)

   The total milligrams of peptide in your vial, shown on the label (commonly 5 mg or 10 mg).

2. 2

   Enter your BAC water (mL)

   How much BAC water you add (mL). This sets the concentration — more water makes it more dilute (more units per dose); less water makes it more concentrated (fewer units per dose).

3. 3

   Enter your target dose (mcg)

   The amount you want per injection, in micrograms. Note that 1 mg = 1,000 mcg.

4. 4

   Read your result: units = clicks

   The calculator returns the number of units to draw, which is the same as the number of clicks on your pen. Dial that many clicks, prime if needed, and dose per your protocol.

How your RefillPen measures

Every RefillPen measures the same way: each click of the dial moves the plunger a fixed 0.01 mL, on the same U-100 scale as an insulin syringe. That is why the calculator's answer works on any of our pens — the only difference between models is how many clicks they dial in one injection.

• ✓1 click = 1 unit = 0.01 mL. The dial moves in whole clicks, so a dose is always a whole number of units.
• ✓A full 3 mL cartridge holds 300 units (300 clicks).
• ✓The V1 dials up to 80 units in one injection; the V2, V2.5 Slim Hybrid and V3 dial up to 60.
• ✓Pen units match U-100 insulin-syringe units: 10 units on the pen is the same volume as 10 units on a U-100 syringe (100 units = 1 mL).
• ✓Prime before you dial: line up the black plunger with the gray stopper and purge one unit to confirm it's correctly lined up before you dial a dose. Re-prime each time you swap cartridges.
• ✓Wondering which peptides work with RefillPen? See the peptide pen compatibility guide.

Clicks to volume

How much each pen dials in one injection

How the math works

1. Concentration = peptide in the vial (mg) ÷ BAC water added (mL). A 5 mg vial with 2 mL of water is 2.5 mg/mL.
2. What one click carries = concentration × 10, in mcg — one click is 0.01 mL, and 1 mg = 1,000 mcg. At 2.5 mg/mL, one click carries 25 mcg.
3. Units (clicks) to dial = your target dose (mcg) ÷ what one click carries. A 250 mcg target at 25 mcg per click is 10 clicks.
4. Doses per vial = (vial mg × 1,000) ÷ target dose (mcg), rounded down. A 5 mg vial at 250 mcg is 20 doses.
5. Doses per 3 mL cartridge = 300 ÷ units per dose, rounded down. At 10 clicks a dose, that is 30 doses.

What one click carries at common mixes

Reference math only — not a recommendation. What a click carries depends only on the peptide in the vial and the water you add; the pen itself always moves 0.01 mL per click.

mg → mcg conversion

1 mg (milligram) = 1,000 mcg (micrograms).

Worked example

Say your vial holds 10 mg and you add 1 mL of BAC water — a concentration of 10 mg/mL. For a 250 mcg target dose, the calculator returns 2.5 units, so you would choose 2 clicks (≈ 200 mcg) or 3 clicks (≈ 300 mcg), whichever sits closest to your protocol.

Peptide pen dosage calculator FAQ

How many clicks is my peptide dose?

On a RefillPen, one unit equals one click. Enter your peptide (mg), the BAC water you added (mL), and your target dose (mcg); the calculator returns the units — and therefore the clicks — to dial.

How much is 1 click on a peptide pen?

On a RefillPen, one click is one unit: 0.01 mL of liquid. How much peptide that carries depends on your mix — concentration (mg/mL) × 10 gives the mcg in one click, so a 5 mg vial with 2 mL of BAC water carries 25 mcg per click. The calculator shows it for your own numbers.

What does adding more BAC water do?

More BAC water makes the solution more dilute, so each dose takes more units (clicks). Less water makes it more concentrated, so each dose takes fewer units. The peptide amount per dose is the same either way — only the volume changes.

What is a unit on the RefillPen?

A unit is one click on the pen, equal to 0.01 mL drawn (a U-100 basis). The calculator converts your target dose into that unit count.

How many units are in a peptide pen?

A full 3 mL cartridge holds 300 units. In one injection the V1 dials up to 80 units, the widest range in our lineup; the V2, V2.5 Slim Hybrid and V3 each dial up to 60. On every model one click is one unit.

Are pen units the same as insulin syringe units?

Yes. RefillPen units are on the U-100 scale — the same as a U-100 insulin syringe, where 100 units = 1 mL. 10 units on a U-100 syringe is the same volume as 10 clicks on the pen.

What's the difference between a 60-unit and an 80-unit pen?

Only how much it dials in one injection: up to 60 units (0.60 mL) or up to 80 units (0.80 mL). Every click is the same 0.01 mL on both, so the calculator's result works on any RefillPen — if it's over 60 units, only the V1 dials it in a single injection.

What if the result isn't a whole number of clicks?

You can only dial whole clicks, so the calculator shows the two nearest whole-click options and the actual dose each one delivers, letting you pick the closest to your target.

How do I calculate a peptide dose for a pen?

Work out the concentration first (peptide mg ÷ BAC water mL), divide your target dose by that concentration to get the volume per dose in mL, then multiply by 100 to get units (clicks). The calculator above does all of this automatically from your three inputs.

How many units should I draw?

Units = (target dose ÷ concentration) × 100. Enter your numbers above and the calculator returns the exact unit count — which on a RefillPen is the same as the number of clicks.

How many doses are in a 3 mL cartridge?

Divide 3 mL by your per-dose volume. At 0.1 mL per dose that's 30 doses from one cartridge; at 0.05 mL per dose it's 60. The smaller each dose, the more doses a single $1 cartridge delivers.

How many doses are in a vial?

Multiply the vial's milligrams by 1,000 and divide by your dose in mcg, rounding down — a 5 mg vial at 250 mcg per dose is 20 doses. The calculator shows doses per vial and per 3 mL cartridge under your result.

Do I need to prime the pen?

Yes. Line up the black plunger with the gray stopper and purge one unit to confirm it's correctly lined up before you dial a dose. You can swap cartridges in and out of one pen — just re-prime each time.

How do I convert mg to mcg?

Multiply milligrams by 1,000: 5 mg = 5,000 mcg, 2.5 mg = 2,500 mcg. The conversion table above lists the common values.