Nitric Oxide (NO) Boosters.

Most NO boosters have one thing in common: their active ingredient is arginine. However, they usually contain a whole host of ingredients that bump up the effectiveness of L-Arginine. Nitric oxide, a gas produced naturally in the body, is responsible for numerous processes, but the most important for bodybuilders is vasodilation: NO causes the smooth muscle cells of blood vessels to dilate, allowing more blood to flow through. The more blood flow, the more oxygen, nutrients and anabolic hormones your museles can get to fuel workouts, repair post-workout damage and ultimately grow.

NO-boosters are mainly used by avid weight-lifters and body builders to achieve more "pump" (blood vessel dilation causing more blood flow to muscles). Personally, I take little to no NO boosters for my regimen. Sometimes, the creatine compound I drink has 1 gram of L-Arginine (NO booster). I haven't really been able to tell the difference when I've used it. If you are really enthusiastic about about beginning a strict training regimen, I recommend you try this a 2 months after implementing whey-protein, casein protein, glutamine, and creatine into your nutrition. In the meantime, more blood flow can be achieved through pre- and post- workout stretching, and great lifting technique.

Glutamine.

Glutamine is the most abundant amino acid (building block of protein) in the bloodstream. It is considered a "conditionally essential amino acid" because it can be manufactured in the body, but under extreme physical stress the demand for glutamine exceeds the body's ability to make it. Most glutamine in the body is stored in muscles followed by the lungs, where much of the glutamine is manufactured. Glutamine is important for removing excess ammonia (a common waste product in the body).

When the body is subjected to strenuous exercise, glutamine levels in muscles drop. In hard training, such as multiple forms of exercise per day, for example lifting and running; it is prudent to supplement glutamine in your diet.