Nitric Oxide, or NO ( also known as Arginine-Alpha-Keto-Glutarate or AAKG) is a gas produced by the body from the amino acid Arginine. It's a cell signaling molecule that is involved in numerous functions, some of which include controlling nutrient delivery, and initiating hemodilation, which is the widening of blood channels. NO enhances the “pump” sensation we get from exercise, this is referred to as “cell expansion” or “cell volumization”. One of the reasons enhancing the pump is important is that nutrients are delivered faster and waste products are removed faster, allowing for faster recovery between sets and between workouts and ultimately better workout performance because you're getting fuel to your muscles faster.
As to the history of this reasonably new supplement: in 1998, Robert F. Furchgott, Louis J. Ignarro and Ferid Murad discovered that nitric oxide is a signaling molecule in the cardiovascular system. They all jointly received the Nobel Prize in Medicine for this discovery. However, it was Ed Byrd who brought NO to the bodybuilding world in 2001-2002 under the company he founded: MRI. Ed Byrd has a long history with bodybuilding – he co- founded EAS and was involved in bringing creatine to market ( Phosphagen). In fact, he refers to himself as “Mr. Creatine”. It was his product – NO2 – that first hit the bodybuilding world, soon to be followed by tons of competitors. I remember working for a major supplement retailer at this time and meeting Ed for a “tour” of stores to promote NO2 – we had an exclusive on the product. He was quite a character and was only to happy to share “ insider” stories of the founding of EAS and his own contributions to the industry. I remember getting 10 -12 bottles as free
samples, I liked the product from Day #1 and see it as a cornerstone supplement for serious lifters.
- Primary benefit: Hemodilation
As stated above, wider blood vessels leads to increased blood flow meaning faster muscle recovery, faster gains in muscle mass, and increased strength and endurance.
NO can also help you achieve a "perpetual pump" - a muscle pump that stays in its blood-filled, hard condition all day long. Yes, you can feel it all day! As well, NO is tied into cell volumization or cell expansion, the currently big thing in supplements. In fact, this is a huge product category. What is cell volumization? It's a common, popular term referring to the hydration state of the cell. The volume of fluid within the cell has been shown to help regulate a number of physiological processes. As an example, research has shown that cell swelling decreases protein breakdown while stimulating protein synthesis.
Cell volume has also been shown to influence the expression of several genes; the activity of various enzymes; the impact of hormones on the cell (e.g., insulin and glucagon); and help regulate metabolism by modifying responsiveness to signaling molecules. Additionally, the concept has given way to a new theory of muscle growth called sarcoplasmic hypertrophy which means you are increasing the volume of the sarcoplasm, the jelly-like substance that surrounds and baths the myofibrils in your muscle cells with nutrients such as water, amino acids, creatine and glycogen. There are several current theories of muscle growth, this is one of the newest and more popular theories and helps explain why cell volumization is a very big thing today. With this concept you are causing the muscles to pump and swell causing the fibers to stretch beyond normal. In theory this translates into new muscle growth and increased strength. While the pioneer product for this category was creatine, NO fits in nicely with the concept. In fact, most users wisely combine nutrients for this purpose to achieve a greater effect.
As far as evidence, there are studies on this product but this is one of the few supplements you can actually feel working – typically within a few days of use you will notice that perpetual pump – you're pumped all the time. Does it work for everyone? No, probably not. Will it work for most people? Yes, it will. Regardless, here are some studies on the product:
A study at Baylor University's (Texas) Exercise and Sports Nutrition Lab examined the effects of AAKG supplementation during training on body composition and training adaptations in experienced gym rats (16). Thirty-five resistance-trained males were matched according to fat-free mass and randomly assigned to ingest supplements containing either a placebo or commercial AAKG supplement in a double blind manner. Subjects took four grams of the supplements three times daily (12 grams per day) for eight weeks during standardized training. There were no significant changes in body mass or body composition. However, there were significant changes in strength levels. The bench press one repetition maximum (1RM) was greatly increased over the eight week period for the AAKG group. Specifically AAKG supplementation helped subjects add an average of 13 pounds to their bench press max over the placebo group during the eight week testing period. Although body composition did not change during the study a longer duration experiment may have shown an increase in lean muscle mass for the AAKG group. In fact muscle mass is often accompanied by changes in strength as seen in most studies but may take as long as 12-16 weeks to fully maximize physiological responses and processes in terms of muscular hypertrophy (18). This study shows that AAKG supplementation may augment 1-RM strength in response to training, but does not appear to significantly affect body composition. However, it could be argued that such a significant increase in strength levels would eventually lead to increased muscle hypertrophy if the testing period would have continued for an extended period of time.
One of the older studies relating to nitric oxide was done by Elam et al (19) in which subjects who received a form of nitric oxide supplement produced greater total gains in strength and lean body mass while on a high intensity strength training program compared to a placebo group on the same exercise regime over the same five week period. Of further interest in this study was that nitric oxide also enhanced recovery from chronic stress by decreasing tissue breakdown as shown by lower urinary hydroxyproline (UH) levels. It also appears that from certain studies done by Friedl et al (20) higher levels of nitric oxide in the body are correlated with enhanced immune function.
In another study by Nagaya et al (21) the supplementation protocol required that each subject consume 1.5 g of arginine per 10 kg of body weight per day for 7 days. A significant increase in peak oxygen consumption was observed. A possible mechanism to describe this increase in performance is the role that arginine has in augmenting nitric oxide. An increase in nitric oxide bio-availability results in coronary vessel vasodilatation and flow, which in turn may positively influence coronary function.
This is, in all honesty, one of those products you either love or hate. The single best way to determine how well it works is to buy a quality product and test it out. Trust me, you will know within a week if it's working.
There are so many products and product categories from this one nutrient it's hard to know where to begin! Perhaps the biggest category is the pre-workout drink category, with products such as NO-Xplode, SuperPump and so on. These are the drinks that typically contain a lot of caffeine – for training energy – as well as aminos in different combinations and several nutrients that support cell expansion along with NO. Some of the pre-workout powders do not contain caffeine but the number is quite small. NO also comes alone by itself as a tablet of capsule, or with other nutrients that enhance the effects of NO. A great example of this would be Nitrix by BSN, one of the top products on the market. There are so many choices that careful label reading is a must, as is buying to your goal.
Timing will depend on the type of product – pre-workout drinks are taken pre workout. Adjust the dosage to your tolerance of caffeine for best results and realize that if you overuse the product you will not get the same energy boost – that's the nature of caffeine, your body adjusts to it. The standard NO caps and tabs are taken 3 times a day on an empty stomach – be sure to spread it out evenly. I usually spread it out so I'm taking it every 4 hours and I also recommend stacking it with creatine for even better results.
Dosage should be as directed on the label. One thing, with the standard NO products, you will be advised to take 3-4 at a time. At 3 times a day, it can be costly so I would consider that when making your buying decision.
16. International Society of Sports Nutrition Conference Proceedings. Sports Nutrition Review Journal, 1: S1-11, 2004.
18. Baechle, T., Earle, R., Essentials of Strength Training and Conditioning. National Strength and Conditioning Association. 2000.
19. Elam RP, Hardin DH, Sutton RA, Hagen L. Effects of arginine and ornithine on strength, lean body mass and urinary hydroxyproline in adult males. J Sports Med Phys Fitness. 1989 Mar; 29(1): 52-56.
20. Friedl R, Moeslinger T, Kopp B, Spieckermann PG. Stimulation of nitric oxide synthesis by the aqueous extract of Panax ginseng root in RAW 264.7 cells. Br J Pharmacol. 2001 Dec; 134(8): 1663-70.
21. Nagaya N, Uematsu M, Oya H, Sato N, et al. Short-term oral administration of L-arginine improves hemodynamics and exercise capacity in patients with precapillary pulmonary hypertension. Am J Respir Crit Care Med. 2001; 163: 887-891.