Supplements that reportedly increase nitric oxide levels within the body are currently being marketed as powerful muscle builders. The marketers of these supplements claim they increase nitric oxide levels within muscle tissue and a dramatic increase in muscle size, strength is experienced. Other claims also include an increase in fast-twitch muscle fiber strength, endurance, power output, and load capacity from taking these supplements. These reported benefits are quite specific, so I decided to scan the literature for the scientific evidence that supports these claims.
Nitric Oxide – what is it?
Nitric oxide is a colorless, free radical gas commonly found in tissues of all mammals (it’s also prepared commercially by passing air through an electric arc). Biologically, nitric oxide has been shown to be an important neuro-messenger in a number of vertebrate signal transduction processes. Nitric oxide is used in medical treatment; for example, nitroglycerin ameliorates the pain of angina by supplying nitric oxide to the blood vessels that supply the heart. The popular drug Viagra controls erection by regulating nitric oxide in the penile cartilage chamber.
The Research and the Claims
I don’t know where the marketers obtained their literature on nitric oxide. It looks like they are using the same journals as the companies selling Myostatin inhibitors – Alice in Wonderland. Although nitric oxide acts as a cell-to-cell communicator for certain metabolic functions, muscle growth is not one of them. After a review of the available literature I cannot find any research that remotely indicates increasing nitric oxide levels plays a part in increasing protein synthesis, contractile strength or any other biochemical pathway that may lead to increases in muscle mass.
For a company to claim their supplement increases “fast-twitch” muscle strength, the promoters must have instigated or funded some kind of research that involved biopsy procedures and histochemical analyses to extract, assesses and identify these particular muscle fibers from animals or humans, before and after supplementation. However, I could find no documentation (either on their web sites or via a literature scan) that details these findings, only the marketing claims. As far as I’m aware, there is zero scientific evidence supporting the notion that nitric oxide supplements increase “fast-twitch” muscle strength.
There also appears to be no evidence whatsoever that shows increasing nitric oxide levels enhances endurance, power output, and load capacity.
Arginine alpha-ketogluterate is the “active” ingredient reported by one company that sells this type of supplement. It is claimed that this compound increases and maintains a constantly high level of nitric oxide in muscle. Nitric oxide is synthesized within the body using the amino acid arginine, the energy cyclic substrate NADPH, and oxygen. Nitric oxide diffuses freely across membranes but it is a transient signaling molecule. Nitric oxide is by nature, a highly reactive gas that has an extremely short life – less than a few seconds. While there is a lot of research on the effects of nitric oxide, there is no research that shows supplementation with arginine alpha-ketogluterate increases or sustains nitric oxide levels in any human or animal organs.
Can you imagine, a supplement that “creates dramatic increases in muscle size, strength, endurance, power output, and load capacity”, but not a single study to support these claims. Nothing new here. Unfortunately, this is typical sports nutrition marketing bullshit. It's sad, misleading, and shows you just what these companies think of the intelligence level of their target market.
When new products burst onto the market, you the consumer can cut through the advertising hype quite easily. Simply ask the supplement company making the claims to "show you the research". A reference is a start, but the actual research study is particularly what your after. You want to see the study, the protocol, the outcome and the University at which the study was conducted. In the present case, you want to see a study showing were this supplement actually increased nitric oxide above a control group, and you want to see the data that demonstrates an increase in lean muscle mass, significantly more than the group without elevated nitric oxide levels.
The fact is, there is no science supporting any of the claims made for so-called nitric oxide supplements. There is no science showing they have any effect on nitric oxide levels and certainly no science showing in effects on muscle growth or increased performance.
Ask yourself why there is no research to support these companies’ wild claims. The simple answer is that research is expensive, make believe products are not. Research provides evidence, fraudulent supplement marketing only delivers hype. It’s far more financially rewarding to sell hype than to produce effective supplements backed by science.
One promoter of a nitric oxide supplement claims to have “brought creatine supplementation to the market” and that their supplement is “the perfected version of creatine”. I’m not sure which market is being referred to but creatine has been used as a supplement for over 40 years. And in NO way are nitric oxide supplements a “perfected version of creatine”. They are nothing like creatine. While creatine is backed by a wealth of research, nitric oxide supplements do not have a shred of scientific evidence that justifies their effectiveness as a bodybuilding supplements.
Bottom line, money spent on these products is money flushed down the toilet.
Read the Real Science
1. Nathan C. Nitric oxide as a secretory product of mammalian cells. FASEB J 1992 6(12):3051-64.
2. Mayer B; Hemmens B. Biosynthesis and action of nitric oxide in mammalian cells. Trends Biochem Sci 1997 22(12):477-81.
3. Janabi N; Chabrier S; Tardieu M. Endogenous nitric oxide activates prostaglandin F2 alpha production in human microglial cells but not in astrocytes: a study of interactions between eicosanoids, nitric oxide, and superoxide anion (O2-) regulatory pathways. J Immunol 1996 1;157(5):2129-35.
4. Esposito C; Cozzolino A; Porta R; Mariniello L; Buommino E; Morelli F; Metafora V; Metafora S. Protein SV-IV promotes nitric oxide production not associated with apoptosis in murine macrophages. Eur J Cell Biol 2002 81(4):185-96.
5. Eckmann L; Laurent F; Langford TD; Hetsko ML; Smith JR; Kagnoff MF; Gillin FD. Nitric oxide production by human intestinal epithelial cells and competition for arginine as potential determinants of host defense against the lumen-dwelling pathogen Giardia lamblia. J Immunol 2000 1;164(3):1478-87.
6. Kelly RA; Smith TW. Nitric oxide and nitrovasodilators: similarities, differences, and interactions. Am J Cardiol 1996 30;77(13):2C-7C.
7. Stryer L. Biochemistry 4th Ed. Freeman & Co. 1997.
