Vialwise

Syringes & pens

What the markings mean, why the same dose reads differently on each device, and how much liquid a needle wastes.

U-100 insulin syringes

Same scale on all three: 1 unit is 0.01 mL. A smaller barrel spreads the marks out so small doses are easier to read. Each is drawn here at 20 units.

51015202530 U-100 · UNITS
0.3 mL · 30 units · a line every unit (some brands add half-units)
5101520253035404550 U-100 · UNITS
0.5 mL · 50 units · a line every unit
102030405060708090100 U-100 · UNITS
1 mL · 100 units · usually a line every 2 units
0.511.522.53 mL
3 mL standard syringe · marked every 0.1 mL; good for adding BAC water, too coarse for small doses

Peptide pen (3 mL cartridge)

Reusable pens take a standard 3 mL cartridge. You dial a number of clicks, and each click pushes the cartridge stopper forward by a fixed volume.

1 mL 2 mL 3 mL 25 CLICKS 12345
Dialed to 25 clicks with a full 3 mL cartridge. The dashed band is the volume this dose pushes out.
  1. 1Pen needle (screws on)
  2. 2Cartridge holder with window
  3. 3Cartridge stopper
  4. 4Dose window (clicks)
  5. 5Dial and push button

Most pens move 0.01 mL per click, so 1 click equals 1 unit on an insulin syringe, and a 3 mL cartridge holds 300 clicks. Some pens use other increments; set yours in the calculator’s pen settings. Priming shots use a few clicks per injection, and the calculator counts them.

1 unit = 0.01 mL

Every U-100 syringe uses this scale. 10 units is 0.1 mL; 100 units is 1 mL.

Units measure liquid

How much peptide one unit holds depends on the water you added. Double the water and each unit holds half as much.

IU is a different unit

HGH and HCG are labeled in IU, a measure of the drug itself. Syringe units still measure volume, and Vialwise keeps the two apart.

There are no 2 mL insulin syringes

U-100 insulin syringes top out at 1 mL. 2 mL and 3 mL syringes are marked in mL and suit mixing, not small doses.

Dead space: the liquid you never inject

After you push the plunger all the way, a little liquid stays in the needle and the hub that joins it to the barrel. It leaves the vial with every draw but never reaches you, so a vial gives fewer doses than the arithmetic says.

Insulin syringes with a built-in needle are a low dead space design: the stopper meets the needle, so almost nothing is left. Syringes with a detachable needle trap more. Low dead space detachable needles have been measured at about 17 µL, and conventional ones at up to 84 µL.

Pick your needle type under Needle & waste in the calculator and the doses-per-vial figure accounts for it.

BUILT-IN NEEDLE stopper meets the needle: almost nothing left DETACHABLE NEEDLE liquid trapped in the hub and tip
Detachable needles trap liquid in the hub.

Pre-mixed vials

Some vials arrive already in liquid form, with a strength printed on the label such as 10 mg/mL. There is nothing to reconstitute. Choose Already liquid in the calculator and enter the strength and the volume in the vial.