Do we need the backstory? It's space PCP for war. Jokes aside, look at how many times in war, we (and I mean a collective we because numerous countries have done this over the last century+) have given soldiers, pilots, etc amphetamines and more in order to improve their ability to fight, stay awake, and win the war.

M'Benga made a future drug that does all this which he prefers people don't use but keeps it just in case he has to save people or survive battles.

That's all the explanation I need. Old Trek didn't give us even that much most of the time - just treknobabble.

Think of it as trek adrenaline/speed/meth. In war, governments often try to find drugs they can give soldiers to enhance performance.

@williams_482 @triktrek Many fans react badly to the P-12 serum as a lazy plot device, but consider: In key battles, it’d make tactical sense for Klingons to draw Fed soldiers into hand to hand combat, because they’re typically experienced blade warriors. It would then be attractive to the Fed to develop something like P-12 as a counter-tactic. Then consider there is a potential sub-plot exploring the ethics of humans revisiting their Eugenics Wars-era mistakes.