What is the difference between n-acetyl-l carnitine and acetyl-l carnitine? how do they affect me?

No difference: Both Amino Acid molecules are similar in action, & both are formed naturally in the body from carnitine, which is found in protein rich foods. The acetyl forms of carnitine get into the brain bettter than carnitine. It is used to make enery, to turn fats into energy. Research has shown possible benefits for men with fertily problems, for memory enhancement and in early alzheimers.