Nitric oxide is a colorless gas produced in the body as a cellular messenger and potent vasodilators. It is synthesized from L-Arginine, Oxygen and Nicotinamide Adenine Dinucleotide Phosphate, NADPH, by nitric oxide synthase enzymes in the body.  It communicates between cells in the body because of its ability to permeate the various cell membranes. As a vasodilator, it causes smooth muscle relaxation in vessels leading to blood pooling. This leads to increased duration of time for tissues to absorb oxygen and other nutrients from the blood.

It is also cardioprotective. This is because with the vasodilatation caused, the blood pressure drops. This relieves the heart of overload and reduces the work load. The levels of NO are higher in people living in higher altitudes. This is to enable their pulmonary tissues to dilate and enable the lungs to filter all the oxygen from the blood into the circulation. For people who are undertaking bodybuilding, athletics and fitness, NO is quite useful as it allows for faster muscular recovery from exercises and leads to increased muscular strength.

Nitric Oxide is available in the form of Nitric Oxide supplements. They increase the amount of the gas in the body. NO2 supplement increase the production of hormones such as adrenaline and noradrenaline. Adrenaline increases blood flow to the muscles and increases blood sugar levels. The increased blood sugar levels provide a substrate for energy production. Bodybuilders use nitric oxide supplements for this reason. With constant exercises and supplementation, there is adequate energy for muscles to perform the intense exercises. The vasodilatation and increased blood flow to the muscles also allows for greater oxygen and nutrient absorption by the muscles and they recover faster from the exercise. With time, there is increased muscular strength, muscle mass and increased overall performance.

The best nitric oxide supplement provides the user with the driving force to work out for longer and harder. It also reduces the amount of lactic acid and ammonia produced by muscles. This is because it ensures enough oxygen is delivered to muscles to cater for the anaerobic stress that muscles are subjected to during exercises.

Most of the best nitric oxide supplements available in the market contain L-Arginine, L-Citrulline and other antioxidants. These compounds form the substrates that are used by the body to synthesize nitric oxide. Most companies combine all the precursors in their products. They are used by the body to synthesize NO before and after workouts. They usually come in powders or shakes. The liquid formulations are easily digested hence more preferable for most people.

Arginine in supplements also stimulates the production of human growth hormone by the pituitary.  Research done showed that there are higher levels of human growth hormone circulating in the body after supplementation with L-Arginine as compared to levels following exercises. The human growth hormone is beneficial to a body builder as it leads to increased muscle mass by both hypertrophy and hyperplasia. There is increased lipolysis and bone mineralization leading to more strength and bulking. Arginine increases the levels of growth hormone by inhibiting the action of Somatostatin, the hormone that gives a negative feedback to the pituitary gland to stop growth hormone production.

Citrulline is better absorbed by the body compared to Arginine. Once absorbed, it is converted to Arginine by the kidneys resulting in higher levels of Arginine. Another additional benefit of Citrulline is that it leads to production of Ornithine which reduces fatigue in muscles post a workout.

Despite the many benefits of nitric oxide supplements, over use of the products has been associated with some adverse reactions and for this reason, caution should be taken.