Put me down as tremendously cynical about "smart drugs." Whatever chemical cycles you might overclock have little to do with intelligence, and for that matter intelligence itself is a poorly defined abstraction. All the phenomenon has shown is that a lot of people understand their own minds as things that draw their power from outside.

What you want is critical thinking and technically flawless symbol-use. What you need is to spend 10 years reading really smart books by yourself.

My literal advice to anyone is to find the biggest, densest, most scholarly book that interests you and read it cover-to-cover. Take as much time as you could possibly need. Get to know it intimately, so much that you can explain the logic of its internal structure, terminological choices, etc. Then try to identify the book that that book's author read, or argued against, and repeat. Take as much time as you need. Your quality of intellectual life will skyrocket.