system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout] What are stimpaks? How do they work?

[Assuming F:NV hard-core mode is canon, with the JSawyer mod - so Stimpaks heal over time, they don't fix broken limbs, the ones you make are weaker than found ones]

What exactly are stimpaks? How do they work? They get your right back in shape after a few shoot-outs, but I still don't get how they work, or what they were originally made off.
gpt
Typically they are composed of certain chemicals that stimulate your body's natural healing mechanism, which is why it won't fix a crippled limb or reduce irradiation symptoms. It can only fix injuries you could recover from naturally, just much faster. It also contains immune boosting drugs to ward off infection and a mild coagulant to help your body stop bleeding faster. These two are not found in the wild and must be produced in a lab, which is why your homemade stims seem to lack the punch of manufactured ones.