Complex Anabolic Effects of BCAA
Kacper Nowak
2026-03-15
4 min. read
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Dietary supplements are means of compensating for nutrient deficiencies in our diet, but some of them are specifically designed for individuals who engage in physical activity, as intense physical exertion can contribute to the forced degradation of muscle-building proteins, resulting in muscle loss. To prevent this and achieve muscle growth, we need to provide the body with appropriate conditions for recovery. This means not only rest, but also adequate supply of specific nutrients that aid in repairing damaged muscles. One of the most important elements that an active individual can provide is branched-chain amino acids, which can be found in food, but also on the shelves of supplement stores under the name BCAA (branched-chain amino acids). These amino acids are generally considered beneficial, but few are aware of their potent effects. It is possible to distinguish as many as four different mechanisms through which these amino acids promote muscle mass development.
Process of Commencing Muscle Protein Synthesis
Muscles that undergo strength training generate an anabolic effect that leads to their growth. Muscle tissue must grow to adapt to imposed demands. To achieve this, muscle cells begin to absorb larger quantities of amino acids, which are then used to expand the muscular structure using mechanisms that are almost exclusively specific to those cells. This process is known as muscle protein synthesis and is regulated by several minor markers, such as the absorption target of aminosin (mTOR) or the growth kinase of 70S6K. Furthermore, it is surprising that training leads muscles to grow through this mechanism, but even more surprising is the fact that branched-chain amino acids activate the same growth markers for cells while simultaneously stimulating muscle protein synthesis. The kinase mTOR acts like a radar, whose task is to detect the availability of energy and amino acids. Only when both components are present is growth of muscle cells possible.
Arginine Alpha-Ketoglutarate
No other nutrient exhibits the same properties as protein in the context of muscle mass building, not even all amino acids are capable of stimulating muscle protein synthesis. Only certain other essential amino acids such as treonine can stimulate the synthesis of new proteins, but research shows that, in particular, the leucine contained in them has the strongest effect.
Functioning as construction materials
The commencement of muscle protein synthesis can be viewed as the first stage in the muscle-building process, similar to hiring a construction crew to the construction site. They are present and ready for construction, now they just need the materials they can utilize. And here come branched-chain amino acids into play, as these waiting workers use them as construction materials in building. Muscle tissue primarily consists of amino acids, including glutamine, glutamic acid, alanine, taurine, and many others. However, a major component of the construction materials are branched-chain amino acids, which constitute about 14% of all amino acids in muscle cells.
Insulin secretion stimulation
Insulin is a hormone that is typically released after consuming carbohydrates, but numerous studies suggest that certain amino acids may also have insulinogenic properties. This is not because they are transformed into glucose in the liver, but rather because the beta cells of the pancreas responsible for stimulating insulin secretion respond to the presence of branched-chain amino acids. What does this mean for muscle mass? Insulin performs many functions in our bodies, one of which is to inhibit the process of gluconeogenesis in the liver. This means that the production of glucose from other substrates such as amino acids, often derived from muscle tissue, is reduced. If the increase in insulin levels stops glucose production, the need for amino acids is also reduced. Therefore, muscle cells detect the elevated insulin level after consuming BCAA and stop the catabolic process of proteolysis, i.e., the breakdown of muscle proteins.
Reduction in the activity of ubiquitin
BCAAs have an indirect anticatabolic effect through insulin activity, but their contact with muscle cells also has a direct impact on halting proteolysis. All our muscle cells contain small proteins called ubiquitin, which are primarily responsible for marking proteins that will undergo degradation. The two main representatives of this family are MuRF-1 (muscle RING-finger-1) and MAFbx (Muscle atrophy F-box). A study by Marcus Borgenvik at the University of Sweden shows that the intake of BCAA can suppress the activity of these two ubiquitin proteins, which ultimately has a direct anticatabolic effect.