What is an injection pen?

An injection pen is a hand-held device that holds a cartridge of liquid and moves a plunger forward in set steps. Insulin pens are the best-known example. Here the framing is research use only, at the bench.

What is the difference between a pre-filled pen and a pen that uses reconstituted powder?

A pre-filled pen arrives with liquid in the cartridge. A powder format needs diluent and reconstitution math from you. A 2021 crossover trial found liquid Menopur in a pre-filled pen bioequivalent to its powder.

What is a connected insulin pen?

A connected insulin pen, or pen cap, is a newer type of insulin device. A 2023 review in Endocrine Connections describes these devices and weighs their advantages and disadvantages.

What plunger height do the Gansulin, V1, V2 and V3 pens use?

All four pens are built for the 11 mm long rubber plunger used in our clear and amber 3 ml cartridges. Cartridges with a shorter plunger (about 8 mm) are a different format, so match the plunger height.

Can I see the rubber plunger through a clear or amber 3 ml cartridge?

Yes. On both clear and amber 3 ml cartridges the rubber plunger is visible through the glass, and its height can be measured from outside.

Which reusable peptide injection pens does PreppinPeppers carry?

Four: the Gansulin Pen (click-dial, 1 to 60 units), and the V1 (1 to 80), V2 (1 to 60) and V3 (1 to 60), which are draw-and-push. Cartridges, needles and bacteriostatic water are not included unless a kit says so.

Do the pens come with cartridges or needles?

No, not unless a kit says so. The pens take standard 3 ml cartridges and universal 28G to 33G screw-on pen needles. PreppinPeppers does not sell needles.

PreppinPeppers › Facts › Lab article

Injection Pen Basics for the Bench and How Cartridges Work

TL;DR

An injection pen is a hand-held, cartridge-based device that pushes a plunger forward in set steps; at the bench, matching pen to cartridge plunger height

Machine-readable facts for this Lab article. The full page is https://www.preppinpeppers.com/blogs/the-lab/injection-pen.

Facts Index

Fact ID	Category	Entity	Attribute	Value	Source
injection-pen:title	identity	Injection Pen Basics for the Bench and How Cartridges Work	title	Injection Pen Basics for the Bench and How Cartridges Work	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:published	identity	Injection Pen Basics for the Bench and How Cartridges Work	published	2026-10-29	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:author	identity	Injection Pen Basics for the Bench and How Cartridges Work	author	PreppinPeppers Editorial Team	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:topics	identity	Injection Pen Basics for the Bench and How Cartridges Work	topics	injection pen, Guides, research	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:summary	content	Injection Pen Basics for the Bench and How Cartridges Work	summary	An injection pen is a hand-held, cartridge-based device that pushes a plunger forward in set steps; at the bench, matching pen to cartridge plunger height	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-1	content	Injection Pen Basics for the Bench and How Cartridges Work	section	What is an injection pen?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-2	content	Injection Pen Basics for the Bench and How Cartridges Work	section	How does an injection pen work with a cartridge?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-3	content	Injection Pen Basics for the Bench and How Cartridges Work	section	What types of injection pens are there?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-4	content	Injection Pen Basics for the Bench and How Cartridges Work	section	What is a reusable peptide injection pen for lab work?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-5	content	Injection Pen Basics for the Bench and How Cartridges Work	section	What does the research community get wrong when matching a pen and cartridge?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-6	content	Injection Pen Basics for the Bench and How Cartridges Work	section	What makes a good injection pen design?	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:section-8	content	Injection Pen Basics for the Bench and How Cartridges Work	section	Related reading	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:product-gansulin-metal-peptide-pen	products	Injection Pen Basics for the Bench and How Cartridges Work	references product	Gansulin Pen · Reusable Click-Dial, 3 ml (1-60 Units)	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:product-v3-peptide-pen-aluminum-draw-and-push-60-unit-3-ml	products	Injection Pen Basics for the Bench and How Cartridges Work	references product	V3 Peptide Pen · Aluminum Draw-and-Push, 60-Unit 3 ml	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:product-gansulin-3ml-cartridge	products	Injection Pen Basics for the Bench and How Cartridges Work	references product	Gansulin-Compatible 3 ml Glass Cartridge for Pens (10-Pack)	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:product-bacteriostatic-water-30ml	products	Injection Pen Basics for the Bench and How Cartridges Work	references product	Bacteriostatic Water 30 ml Multi-Dose Vial (Pfizer Hospira, USP)	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:source-pmc-ncbi-nlm-nih-gov	source	Injection Pen Basics for the Bench and How Cartridges Work	cites	Jonker et al., Int J Clin Pharmacol Ther 2021: First pre-filled pen device with highly purified human menopausal gonadotropin (HP-hMG, Menopur) in liquid is shown to be bioequivalent to powder for reconstitution - pmc.ncbi.nlm.nih.gov	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:source-pmc-ncbi-nlm-nih-gov-2	source	Injection Pen Basics for the Bench and How Cartridges Work	cites	Lingen et al., Endocr Connect 2023: Advantages and disadvantages of connected insulin pens in diabetes management - pmc.ncbi.nlm.nih.gov	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)
injection-pen:source-pmc-ncbi-nlm-nih-gov-3	source	Injection Pen Basics for the Bench and How Cartridges Work	cites	Sparre et al., J Diabetes Sci Technol 2022: Development of an Insulin Pen is a Patient-Centric Multidisciplinary Undertaking: A Commentary - pmc.ncbi.nlm.nih.gov	Lab article (https://www.preppinpeppers.com/blogs/the-lab/injection-pen) (evidence)

FAQ

What is an injection pen?: An injection pen is a hand-held device that holds a cartridge of liquid and moves a plunger forward in set steps. Insulin pens are the best-known example. Here the framing is research use only, at the bench.
What is the difference between a pre-filled pen and a pen that uses reconstituted powder?: A pre-filled pen arrives with liquid in the cartridge. A powder format needs diluent and reconstitution math from you. A 2021 crossover trial found liquid Menopur in a pre-filled pen bioequivalent to its powder.
What is a connected insulin pen?: A connected insulin pen, or pen cap, is a newer type of insulin device. A 2023 review in Endocrine Connections describes these devices and weighs their advantages and disadvantages.
What plunger height do the Gansulin, V1, V2 and V3 pens use?: All four pens are built for the 11 mm long rubber plunger used in our clear and amber 3 ml cartridges. Cartridges with a shorter plunger (about 8 mm) are a different format, so match the plunger height.
Can I see the rubber plunger through a clear or amber 3 ml cartridge?: Yes. On both clear and amber 3 ml cartridges the rubber plunger is visible through the glass, and its height can be measured from outside.
Which reusable peptide injection pens does PreppinPeppers carry?: Four: the Gansulin Pen (click-dial, 1 to 60 units), and the V1 (1 to 80), V2 (1 to 60) and V3 (1 to 60), which are draw-and-push. Cartridges, needles and bacteriostatic water are not included unless a kit says so.
Do the pens come with cartridges or needles?: No, not unless a kit says so. The pens take standard 3 ml cartridges and universal 28G to 33G screw-on pen needles. PreppinPeppers does not sell needles.