Neuropozyne is a narcotic drug which can meet during the passage of Deus Ex: Mankind Divided. You can collect Neyropozin during the game, and there are several ways to use them. Neuropozyne sometimes is asked for different characters, and if you will share it, you can get some bonuses for it.
You can sell your Neuropozyne on the black market for a lot of money, but save a few pieces fir a good idea. You can exchange it for information, if you find someone suffering from withdrawal.