Originally Posted by einstein1905
I was doing research for a vaccine company.....they were the ones who developed the helium cartridge-powered "needle-free" injectors. They were pretty loud, but they were just in crude form at the time and not in the form that they'd be sold for actual use. Still some pain with them too, and they leave hickey-like marks for a day or so. I'm sure they're improved now, but you need a good amount of force to get something deep IM. Also, not everything is suitable to be administered that way.