I have noticed a resurgence in peeps interest in Amino Acids. "The building blocks of protein" We used to pop em like candy. All of the things they help in the body is pretty amazing. From growth hormone secretion, enhanced protein synthesis to better flow of the blood to penis. (Arginine)
The following I've posted is a reference guide for each Amino Acid....both the regular and Branched Chain. Give it a look, its quite amazing what each of them do individualistically. Consistent use just might be what your body needs to bump it up a notch!

gator

http://www.realtime.net/anr/aminoacd.html