Loading a cartridge pen is a simple, repeatable process. These are the basic mechanical steps for the device, using the Gansulin metal pen and a standard 3 ml cartridge as the example.
This is a guide to getting familiar with how the device works. Always follow the instructions that came with your specific pen.
1. Open the pen
- Remove the pen cap.
- Unscrew the cartridge holder (the front section that holds the cartridge) from the body.
- If an empty cartridge is inside, take it out.
Gansulin Metal Reusable Pen (1-60 Units, 3 ml Cartridges)
2. Seat the cartridge
Place the new 3 ml cartridge into the holder. Put the crimped end first (the crimped end is the sealed metal cap end) so it sits flush against the inside of the holder.
Screw the holder back onto the body until it locks in place. On the Gansulin pen, you will hear and feel a clear click when the cartridge is fully seated.
The needle interface
The front of the holder has a standard screw-on needle port (a threaded opening where a pen needle attaches). Needles are sold separately and are not included with the pen.
How a needle is used is outside the scope of this article, which covers the pen mechanism only.
Standard 3 ml Glass Cartridges for Pens (10-Pack)
Clearing the air gap
When you first load a cartridge, a small air bubble can sit at the top. Hold the pen upright, dial a small amount, and gently tap the holder. This moves the bubble upward. Then push the plunger (the button that advances the mechanism) forward to push the air out.
Think of it like tapping a bubble to the top of a syringe before use. Removing that air bubble keeps the measuring accurate, so the amount you dial matches the amount the mechanism actually moves, one click per unit.
Key point: Clearing the air gap is critical to accurate measuring. It makes sure the amount you dial matches exactly what the mechanism delivers.
3. Set your amount
Turn the dose knob to the amount you want, from 1 to 60 units. Each click is one unit. The number shows in the small window on the pen.
To convert between mg, ml and units, use our peptide calculator.
After use
Put the pen cap back on and store the pen in its case. If any external accessory was attached, remove it and dispose of it properly.
See how a dial-a-dose pen works for more on the mechanism.
Preppin Peppers sells laboratory hardware and consumables for research, educational, and demonstration use only. This article is general educational information about equipment and does not describe, recommend, or instruct the use of any peptide or other substance in humans or animals. Nothing here is medical advice.
Reminder: research and educational reference only. Preppin Peppers sells hardware and materials, not peptides. Not medical, dosing, or health advice, not evaluated by the FDA, and not intended for human or animal use.
Frequently asked questions
Which end of the cartridge goes in first when loading a pen?
Insert the crimped end (the sealed metal cap) first so it sits flush against the inside of the cartridge holder before screwing the holder back onto the pen body.
How do you clear the air gap after loading a cartridge pen?
Hold the pen upright, dial a small amount, and tap the holder to move the bubble upward; then press the plunger to push the air out, ensuring the dial accurately reflects mechanism movement.
How many units does the Gansulin metal pen dial, and how do you read the dose?
The Gansulin metal pen dials 1–60 units; each click equals one unit, and the selected amount appears in the small window on the pen body.
