The so-called muscle mass means in fact mainly the size of contractile protein fibres – contractile, i.e. those that set our body in motion, contracting and relaxing.
Because their size is of great importance for the results in many sports, training focused on the development of muscle mass is an important element in the preparations for competitions. Also, given the strategic importance of the protein mass, anabolic hormones have always dominated in illegal sports doping, since anabolism is the process of building proteins in the body. However, anabolic hormones are detrimental to health, and thus regulations prohibit their use in sport. In view of the above, for years now there have been sought substances facilitating the mass development among the natural, safe food-derived products, called dietary supplements.
While opinions in the community state that no supplement will ever match the effectiveness of anabolic hormones, in light of recent research results these can be considered obsolete.

GUANIDINES

Some of the nutrients contain in their structures the characteristic guanidine molecule and therefore are generally called guanidines. They are mentioned here since it is mainly them that show strong anabolic activity. In this group of nutrients, there may be found substances well known for many years, as well as those that have been included in dietary supplements only recently. There have been many of them identified in the diet, the human body and in herbs, but in the context of supplementation, four of them are mentioned most often: arginine, creatine, glucocyamine and guanidinopropionic acid.
The most characteristic feature of the guanidine molecule is a parameter denoted with the symbol pK by biochemists. Owing to its values, all of guanidines are able to maintain the optimum acidity inside the muscle cells. This is important, since myocytes of athletes become strongly acidified as a result of workout. Acidification promotes the loss of contractile proteins, since enzymes degrading proteins and removing them outside of the body are active only in highly acidic conditions. Thus, guanidines inhibit the activity of destructive enzymes and in consequence save and accumulate muscle proteins – a phenomenon called the anti-catabolic action.
However, apart from the above general property of this group of nutrients, each guanidine also has its unique function, which favours the development of muscle mass.

ARGININE

Arginine is a precursor of gas hormone – nitric oxide – NO. Nitric oxide facilitates the penetration of oxygen, sugar, fat and amino acids into the muscle cells. All these compounds are necessary for the muscles to work and for building the contractile proteins. NO initiates a signal transduction pathway leading directly to the nucleus, triggering the synthesis of new proteins. In this manner, arginine influences comprehensively the development of muscle mass, as evidenced by numerous studies.

CREATINE

This is probably the most popular sports supplement, the anabolic activity of which has been evidenced on numerous occasions, one that does not require a broad recommendation.
The researchers associate the mechanism of its anabolic effects with its property of transporting ATP.
The contractile proteins determining the muscle mass are composed of small building blocks – amino acids. However, every single amino acid is like a building block without the layer of mortar on the edges. A bricklayer cannot erect a wall without mortar, and similarly the body is not able to build muscle fibre out of “pure” amino acids. The role here is played by ATP. It binds to amino acids and converts them into aminoacyl adenylates – building blocks with mortar on them. And creatine? ... Creatine in the form of phosphocreatine delivers ATP to amino acids!

GLYCOCYAMINE

Creatine is a nutrient indeed, but is not delivered to muscles only from food, since the body is able to produce it yourself. However, this production is very sparse and slow, so it does not cover the demand for creatine needed for a fast development of muscle mass. Therefore, athletes often supplement creatine with dietary supplements. But the body's own production can be stepped up as well...
The first step of creatine synthesis takes place in kidneys. The body builds it from another guanidine – arginine. In renal cells, arginine is converted into guanidinoacetate or glycocyamine. The latter travels from kidneys to the liver and only there it is converted to creatine. But when the liver receives ready-made glycocyamine from food or supplements, it immediately produces creatine from it – the first stage (renal synthesis) is skipped. In this manner, glycocyamine does not allow body’s own creatine synthesis pathways to “become lazy” when delivered to the body with a supplement. Owing to glycocyamine, the muscles may be supplied with creatine from two sources – a supplement or body’s own synthesis.
 
GUANIDINOPROPIONIC ACID

Guanidinopropionic acid is an analogue of creatine – a substance composed of identical set of atoms with only a slightly different arrangement. Since conducted studies have shown its strong anabolic effects, the researchers have suspected that this compound, similarly to glycocyamine, is transformed into creatine. When further tests ruled out this possibility, it was thought that it might, just as creatine, deliver ATP to amino acids. But subsequent studies seemed to contradict this notion as well, and not only that – they have shown that supplementation with guanidynopropionic acid lowers the levels of phosphocreatine and ATP in muscle cells. It is easy to imagine the consternation of scientists, since previous studies had shown that the higher the level of phosphocreatine and ATP, the faster the muscle growth. And here – the opposite...
The riddle has been solved by further observations, in which guanidynopropionic acid has been shown to increase the production of other phosphates, such as phosphocreatine, but not from creatine, but from sugar – glucose. These phosphates generate ATP themselves and deliver it directly to amino acids. Phosphocreatine simply transports ATP from the place of its production – where it arises in abundance yet remains inactive. Guanidynopropioniac acid additionally inhibits ATP elimination from its activity sites.
Thus, although in the presence of guanidynopropionic acid the levels of phosphocreatine drop, those of more effective ATP carriers go up. In consequence, the overall reserve of ATP drops, but only at the expense of its inactive stores.

But, in order for phosphates – alternatives to phosphocreatine – to be generated, the muscle cell must intensify the production of protein enzymes that convert prosphates into sugar – glucose. These proteins are formed as a result of the mobilisation of the same signalling pathways that lead to the production of contractile proteins and through which the abovementioned NO acts, as well as stimulate the synthesis of typical anabolic protein hormones – insulin, somatotropin, adrenaline and testosterone.
It is worth noting that the manner of accumulation of contractile proteins observed after consumption of guanidynopropionic acid is characteristic of fast muscle fibres, which generally store the largest quantities of proteins and are responsible for the muscle growth to the greatest extent.

PUTTING IT ALL TOGETHER...

Most of the ideas for enhancing the anabolic activity of dietary supplements focus on combining all guanidines in one preparation. It certainly increases their potency, but it is not the last word from the whizzes in sports diet... Two other nutrients – lysine and norvaline – inhibit the breakdown of guanidine in the body, and the latter appears particularly active in this regard. It is not difficult to guess that, when added to mixtures of guanidines, it substantially enhances their performance!
Based on the trends in combining guanidines with norvaline, there have recently been developed worldwide several permitted dietary supplements to facilitate muscle growth. We also have the first Polish one – Olimp Knockout – designed for all those who desire muscle mass.