The Lab

Units, milliliters and milligrams: reading a U-100 scale
Units, milliliters and milligrams: reading a U-100 scale

What a U-100 unit is, how it relates to milliliters, and how concentration turns units into milligrams, with a worked example and a free calculator. Read more...
How to load a cartridge pen
How to load a cartridge pen

A step-by-step walkthrough of seating a 3 ml cartridge in a reusable pen, attaching a needle, and priming out air, using the Gansulin metal pen as the example. Read more...
Bacteriostatic water vs sterile water: the difference explained
Bacteriostatic water vs sterile water: the difference explained

The practical difference between bacteriostatic water and sterile water for research reconstitution, and how the benzyl alcohol preservative changes shelf life after opening. Read more...
3 ml glass cartridges explained: the 300-unit standard, seals and storage
3 ml glass cartridges explained: the 300-unit standard, seals and storage

What the standard 3 ml / 300-unit glass cartridge is, how the seals work, and how to store sealed cartridges properly. Read more...
How a dial-a-dose pen works: reading the dose window and the click
How a dial-a-dose pen works: reading the dose window and the click

A plain-English tour of the reusable metal cartridge pen: the dose knob, the dose window, the audible click, and the end-of-travel stop. Read more...