Black Powder isn't just an NO supplement. It also contains things like arginine, beta-alanine, creatine, caffeine, and other such supplements that are very beneficial pre-workout. Also copious amounts of b12 (1900% DV). All I know is it seems to have worked quite well on my first trial.
also I found this read quite interesting.
Endocrine and Biochemical Influences: The Pump
Perhaps the single most important influence on muscle growth is what we call
“the pump” or increased blood volume surrounding working muscles. This is known in science as exercise induced hyperaemia. At least one study to date, illustrates that blood flow or lack of sufficient blood flow seems to be a limiting factor for muscle size. Nutrient delivery, removal of fatigue toxins, and important responses of the body when training, are all much more efficient in an environment of higher blood volume, again exercise induced hyperaemia. For example, the physiological process of angiogenesis, which is the growth of new capillaries to feed muscle cells, and enhance oxygen delivery capacity to muscle cells, only occurs when there is increased demand as through chronic training protocol over time. Capillary growth occurs around the glycolytic muscle fibers, (the type 2 fibers) when the stimulus includes increased blood flow, as from training stimulation, or from metabolic demand, or both. So something as important as increased capillary capacity and number occurs from chronic training stimulus, yes, but also is necessitated by a chronic increase in blood flow as well. Increased pump or blood volume (exercise induced hyperaemia) is a result and dependant upon an integrated response of more than one important actor. Vasodilation or increased capacity of the veins and capillaries to expand and handle more blood flow is another example of the response of the body to training and to higher blood volume demands of training. But certain hormones and biochemical factors also play key roles. These aren’t exhaustive by any means but its important to look at the interplay and activity of VEGF (vascular endothelial growth factor), NO2, (nitric oxide) and IGF1, and the roles they play and adaptations they have to both training and to their roles in creating and attenuating exercise induced hyperaemia.
Vascular Endothelial Growth Factor
VEGF is a long-term adaptive response to training. It is suggested that the stretching of skeletal muscle, as in the eccentric phase of lifting is a possible stimulus for VEGF. VEGF is produced by the muscles and can also be secreted into the circulation. Training itself produced a 3 to 6 fold increase in VEGF, its receptors and some other dependant transducers like NO2 synthase (more on that below). Once VEGF is increased it exerts its influence in a number of ways but most notably by increasing myoglobin 2.8 fold. This is important both during training and recovery because myoglobin is the oxygen carrying protein in muscle tissue, and therefore increased myoglobin improves muscle oxygenation. The amount of VEGF produced by the muscles from training is also a direct result of muscle ischemia during training. Ischemia, which means lack of oxygen, in this case lack of oxygen to working muscles promotes angiogenesis, which I mentioned earlier, and myogenesis (creation of new muscle) as well. Since ischemia has a very positive influence on the amount of VEGF your muscles make, and since ischemia is a key factor to myogenesis, VEGF can therefore also be thought of as a key contributor to muscle size. This illustrates the importance of the pump and its effects on muscles and factors that contribute to growth.
NO2 Nitric Oxide and Nitric Oxide Synthase
NO2 interplays in a myriad of factors which have to do with both increased blood flow (yes, exercise induced hyperaemia) and muscle growth. It has direct and indirect influences on both, and many other key players in the muscle growth equation are dependant upon NO2 in order to exert their influence. For example, increases in NO2 also lead to increases in VEGF, and all of its benefits discussed above.
What NO2 is exactly is a signal transducing molecule. There are several noticeable effects of NO2, which again increases in response to training stimuli. NO2 can modify muscle force, NO2 is also important in the development and control of total body sodium, and body fluid homeostasis. Levels of NO2 are controlled by enzymes called nitric oxide synthase. Nitric oxide synthase, like VEGF, increases 3 to 6 fold from the stimulus of training. Of paramount importance, is the fact that NO2 is one of the primary factors in sustaining muscle hyperaemia, so not just getting the pump but also keeping it in order for it to exert all its positive effects including those on muscle growth. So important is NO2 in this manner that some of the nitric oxide synthase enzymes are located within the muscle and some are in the blood vessels themselves. NO2 not only sustains a muscle pump, but also is responsible for attaining maximal muscle pump (muscle hyperaemia). Because NO2 is also within blood vessels, the increase in vasodilatory response to exercise appears not only in the exercised muscles, but systemically (all through the body) as well. Also in response to training NO2 increases its own levels. Therefore one of the more exciting things about NO2 is its myriad of activities in both attenuating and maintaining a pump. Again, NO2 increases itself as a training response, dilates blood vessels, and increases glucose uptake. This in turn as well boosts the pump, which is so essential for growth to occur. NO2 also has a direct influence on satellite cell activation to increase muscle growth. So NO2 works to increase the pump and muscle growth in a variety of ways. And not only does NO2 boost muscle growth itself, but builds muscle as well through its effect of elevating other muscle building hormones like VEGF as I mentioned and just as importantly, IGF1. This is quite obviously one important element in muscle pump and muscle growth.