Insulin can be deadly actually, Humulin R is popular, and its OTC (for now).
yes its popular, but it is does not discriminate against shuttling into fat or muscle, so it takes some education. If you push your luck with your carb level, or carb "release" time, then you could experience sleepiness and/or death. It is advisable to keep soda around the house for these occasions, if you start to feel sleepy, down some soda and dont allow yourself to sleep, even if it means doing something stupid like slapping yourself or dancing naked.
There is alot to study/know before successfully chasing after a slin cycle.
Who makes it? You will find it at your local pharmacy, its for diabetics. You inject with a 1cc pusher and a 27g pin typically, which is small enough to measure your IUs.
I can dig up more info if your curious, but while its almost impossible to die overnight from steroids (you'd have to try hard), slin can be deadly your first time out.