What supplements/herbs/easily attainable drugs can I take to do better at study?

For better concentration/memory etc. Will doctors give prescription study aids if I don’t have any actual illness? Modafinil or adrafinil (not sure if adrafinil is spelt correctly) look interesting, but could I buy them without ordering them? I already take a general vitamin supplement. Thankyou if you can help with any of my questions. Powered…