1. What is it and where does it come from?
Nitric Oxide is a free form gas that is produced in the body and is used by the body to communicate with other cells in the body. To produce this gas, enzymes in the body break down the amino acid Arginine.  Nitric Oxide is a molecule consisting of one atom of nitrogen and one atom of oxygen. The production of Nitric Oxide occurs when the amino acid L-arginine is converted into L-citruline through an enzyme group known as Nitric Oxide Synthase.

2. What does it do and what scientific studies give evidence to support this?
Despite the claims of some in the supplement industry, there exists ample scientific literature to suggest the efficacy of Nitric Oxide products. The following was written in May 1996 in a document prepared for the Royal Society and Association of British Science Writers:
"Summary research papers continue to flood the scientific journals and insights into the biological activity and potential clinical uses of nitric oxide (NO): a gas controlling a seemingly limitless range of functions in the body. Each revelation adds to nitric oxide's already lengthy resume in controlling the circulation of the blood, regulating activities of the brain, lungs, liver, kidneys, stomach and other organs."Since the above was written in 1996, Nitric Oxide containing products have continued to be touted by those in the medical profession, as well as by athletes looking to add muscle to their frames. The above quotation states that Nitric Oxide controls the circulation of blood, and transmits messages between nerve cells.The fact that nitric oxide increases blood flow should make it of interest to bodybuilders, as increased blood flow will serve to deliver more nutrients to muscles, thus helping muscles become larger when subject to stress.*  Nitric oxide also affects the endocrine system. It affects the release of gonadotroptin releasing hormone, as well as the release of adrenaline from the adrenal medulla.

3. Who needs it and what are some symptoms of deficiency?
Everyone REQUIRES nitric oxide to carry out key physiological processes within the body. From a bodybuilder's perspective, nitric oxide supplementation may prove useful in increasing growth due to increases in blood flow to certain areas of the body.*Signs of deficiency include physical weakness and extreme fatigue. Most "nitric oxide" supplements contain the amino acid Arginine-alpha-keto-glutarate.

4. How much should be taken? Are there any side effects?
With any amino acid containing product, overdose is a possibility. Dosing with too much arginine can lead to diarrhea, weakness and nausea. Clear dosing guidelines have not been established, so it is best to do what is known as "tolerance mapping". Take a small dosage for one week, note the benefits and the side effects, and increase the dosage until the benefits are maximized and the side effects minimized. Over time the two will converge and you will hit the optimal dose. This process is similar to "receptor mapping" for bodybuilders who use insulin.

5. What is the best Nitric Oxide product on the market?
Noxavol by CTD Labs is currently the best selling item in the nitric oxide category.  Users report an increase in endurance and vascularity while on Noxavol.  Considered by many top athletes to be the most potent nitric oxide available.