Nitrix

Part A:

In 1998 the Nobel Prize for medicine was awarded to the men who discovered that nitric oxide acts as a signal in the cardiovascular system. Now the supplement company BSN is manufacturing a nutritional product called Nitrix, and are claiming that this product enhances the vasodilating properties of nitric oxide.

Nitrix is a nutritional supplement sold in tablet form, and each tablet consists of:

- 200mcg Vitamin B9 (folic acid)

- 3000mg L-Arginine Alpha Keto-Glutarate

- 1791mg CRTS2 (Controlled Release Technology & Support System) made up of:

o Methocel (Micro-Polymer Hydrophilic Ether Matrix)

o Phosphoplexx (Di-Calcium Phosphate, Di-Potassium Phosphate, Di-Sodium Phosphate)

o CEM3 (Creatine-Ethyl-Ester-Malate)

o L-Citrulline

o NAD (Nicotinamine Adenine Dinucleotide)

- Magnesium Stearate

- Stearic Acid

See Figure 1 in Appendix A for supplement label.

This product claims to function as a "vaso-muscular volumizer" when taken for an optimal cycle length of 12 weeks with a suggested cycle off length of 4 weeks. Users of this product under 200 pounds are recommended to take 3 tablets, 3 times per day on an empty stomach, every day. Users over 200 pounds are recommended to increase this dose to 4 tablets, 3 times daily. The company suggests that doses be taken upon rising, before lunch, and before dinner. It is also noted that glutamine supplements should not be taken at the same time as Nitrix as doing so may diminish its effects. Nitrix is sold at a price of $99.99 for 360 tablets, indicating that users under 200 pounds would get 40 days of use out of one bottle, while those over 200 pounds would get 30 days use.

The makers of Nitrix claim that this product supports maximum nitric oxide levels in skeletal muscles, which volumizes muscle tissue resulting in increased vascularity, tone and muscle hardness (2). This is because nitric oxide is involved in the dilation of blood vessels, which permits more blood to flow into tissues such as skeletal muscle. They also claim that Nitrix promotes tissue recovery, repair, and endurance, and that taking this product will reduce muscle and joint pain and stiffness (2). They market the product by stating that it is used by models and bodybuilders to bring out muscle shape and vascularity before photo shoots. The implied benefits for athletes to use this product are that it amplifies the body's ability to produce and significantly increase nitric oxide to "optimal muscle and performance enhancing levels". Specifically, that enhancing blood flow supports better delivery of oxygen, nutrients, and anabolic substances, and removal of metabolic by-products that are associated with fatigue (2).

Part B:

The physiological and biochemical mechanisms involved when Nitrix is consumed follow the idea that nitric oxide is produced in the body from the amino acid arginine. L-Arginine, the active form of arginine, is converted to nitric oxide and L-citrulline, another amino acid, by enzymes called nitric oxide synthases (NOS) (3). The most highly expressed form of NOS in skeletal muscles is neuronal NOS, suggesting that nNOS is the major isoform of the enzyme involved in exercise metabolism (3). Arginine is a substrate for NOS, which forms nitric oxide (4). Nitric oxide then acts as an effector molecule that is produced by various cell types in the body including endothelial cells, which generate the NO as a vasodilator of the smooth muscles in blood vessels (4). Vasodilation of these smooth muscles may increase blood flow to smooth muscles (5), including skeletal muscle tissue.

When investigated, the research completed does not enforce the claim that increased levels of nitric oxide in the body enhances exercise performance. There has been very little examination of the effect of increases in L-arginine availability during exercise (3). Although some research completed has determined that there are hormonal responses in the body that occur when L-arginine is supplemented at rest, there is no data yet to prove that these same responses occur to some extent during exercise (3). Other studies show that supplementation of arginine and other amino acids significantly elevated serum human growth hormone (hGH) at