Nitric Oxide is a gas formed in the body by the breakdown of L-Arginine to L-Citrulline through an enzyme group called Nitric Oxide Synthase (NOS). Although NO2 is used for many purposes, it's ability to increase blood flow will be discussed in this article.
In general supplement companies claim that NO2 supplements can:
Increase recovery post workout
Increase resistance to muscular fatigue
Increase muscular work output
These three claims are largely based on the assumption that an increase in blood flow to muscle tissue will enable users to experience the claims that supplement companies put forward. Obviously there are many other variable factors that can influence your muscle mass growth and strength gains for example you general diet and training. So the claim is that if your diet and training are in place, taking a NO2 supplement will enable your body to build more muscle mass that the same diet and training regime without the nitric oxide supplementation.
There is absolutely no doubt that NO2 supplements increase blood flow. Just ask anyone how has taken a nitric oxide supplement and they will tell you blood flow is substantially increased. But does this blood flow actually produce the results that are claimed? Or is it mostly a mental advantage from feeling the pump!
Vasodilation
Vasodilation is the process of a relaxation of blood vessels, allowing them to carry more blood to and from working muscle tissue. Vasodilation (to high levels) is triggered by the sunset of exercise as the need for oxygen and nutrients is heightened during this time. The process of vasodilation is highly influenced by nitric oxide.
High levels of nitric oxide aid in the conversion of an enzyme (GTP) into another (cGMP) which serves as an important messenger to, among others, the relaxation of smooth vascular muscle in order to create vasodilatory effects. Therefore, if levels of nitric oxide are inhibited vasodilation may not occur to the amount that allows maximum performance.
In essence, vasodilation occurs when high levels of nutrients need to be transferred into muscles for energy production. Vasodilation itself is highly influenced, and limited by the amount of NO2 that is available as it has been observed that a limited production of nitric oxide can lead to vasoconstriction.
It can be suggested that before that if we can enable the body to produce adequate amounts of nitric oxide, proper levels of vasodilation can occur, enabling the body to transport ample amounts of nutrients to working muscle for maximum power output.
What Should Be Supplemented To Increase NO2 Levels?
Most 'NO2' supplements on the market currently use ingredients such as
L-Arginine
Arginine-alpha-ketoglutarate
L-Citrulline
Citrulline Malate
As nitric oxide is produced by the conversion of l-arginine it can be assumed that supplementing with l-arginine will have an effect on NO levels. However the evidence as yet shows no correlation between oral arginine supplementation and nitric oxide levels. Unfortunately l-arginine concentration does not directly affect the rate of nitric oxide production. Citrulline, the amino acid that l-arginine is converted into in the NO2 conversion process has actually been shown to have a greater effect of nitric oxide levels with oral supplementation. However these amino acids alone do not seem to have a direct effect on nitric oxide levels.
Insulin
Insulin is an incredibly important hormone that allows nutrients, including glucose to be transported to muscle cells and has been shown to be a regulator in vasodilation and blood flow.
It is important to discuss insulin levels as it has been studied that the effects of insulin on vasodilation are dependent on insulin sensitivity ie how much insulin can be released when carbohydrates are ingested. These studies have concluded that nitric oxide production by insulin can decrease in people that are insulin 'resistant' rather than people that are sensitive to the effects of insulin release.
It can be extrapolated that a heightened in insulin levels can produce hyper vasodilation and in fact, this has been shown in resulting studies.
How Can Insulin Be Raised To Spark Vasodilation?
In fact the products mentioned earlier that are used in many nitric oxide products do increase insulin sensitivity in the body, therefore they do increase vasodilation but through heightened levels of insulin rather than a direct effect on l-arginine conversion.
How Are NO2 Supplements Best Supplied?
Insulin has a linear relationship with the ingestion of carbohydrates; if large amounts of carbohydrates are ateen larger amounts of insulin are released. Therefore many powdered NO2 supplements will combine their ingredients with simple fast acting carbohydrates such as dextrose in order to increase vasodilation and 'the pump'. These carbohydrates are shuttled to muscle literally forcing the carbohydrates into the cells and filling them up like a balloon creating a larger muscle mass.
Powdered products are usually taken pre-workout only as supplementation of simple sugars is not recommended at any other time. Nitric oxide pills do not contain the sugars and will produce a slight effect on vasodilation by increasing your insulin sensitivity. Therefore carbohydrate ingestion is recommended around your workout to allow for the greatest chance of vasodilation trough insulin use.
The Claims
Earlier the three most common claims of the supplement companies were stated and in general it can be concluded that NO2 supplements can produce those results (obviously there are other factors that can influence this). If vasodilation occurs with an increased insulin response from supplementation of NO2 products it can enable users to gain better results from supplementation.