Movie where testing a drug on serial killer inmates to fix them?

I'm trying to recall the name of a movie I saw a long time about - the premise is following the testing a miracle drug that is supposed to bring psychopaths / serial killers back to being "human" by giving them the ability to feel feelings and compassion for their victims again.

I don't think it had any famous actors in it.

Any ideas?

Thanks as always for anyone's participation, I really appreciate it.

Maybe Control (2004)?

That's it!! THANK YOU SO MUCH! I don't know why google and movie finders are so bad at finding these things!

Maybe my search terms are just really bad.

You're welcome!