Undoubtedly, of all the hormones, testosterone is the one most associated with lean mass gain. It is not by chance that its use and its derivatives, as well as products that promise its natural increase, known as testo boosters, are common among bodybuilders.
The question, then, is: “the higher my testosterone levels, the greater my mass gain?”. And the answer is: Not exactly.
Through hormonal physiology, we know that a certain hormone only exerts its biological function after binding to its receptor (which can be located in various tissues of our organism) and, then, starting a series of metabolic reactions. Therefore, the amount of hormone that is still circulating in the plasma, identified through biochemical tests, is not yet bound to the receptor and, therefore, is not performing its expected function [1].
In the case of testosterone and the hypertrophy process, what we expect is that the hormone binds to the receptor located in the skeletal muscle and that, then, there is a signal to increase protein synthesis or prevent degradation. However, the acute increase in the levels of intramuscular testosterone and its derivatives does not predict gains in men who practice bodybuilding [2].
More important than circulating and intramuscular levels, what we must consider is the density of androgen receptors contained in skeletal muscle. That is, the more androgen receptors you express in your muscles, the greater the response to the hormone. This was demonstrated in 2018 in the study conducted by Morton and his colleagues. In summary, in this study, the researchers were able to conclude that the density of androgen receptors, and not hormones (testosterone and its derivatives) at the intramuscular level, influences the hypertrophy process in young men who practice bodybuilding.
So now the question is: What should I do to increase this androgen receptor density?
Well, about that, certainly the first most impacting factor is genetics. This explains when we see bodybuilders, without the use of anabolic steroids, with high physiological levels of testosterone and who do not have a greater volume of lean mass even when training and eating properly. At the same time, the opposite is true. There are men with relatively low levels of testosterone, but who have a physique that calls into question the use of steroids. Not to mention that, sometimes, the latter don't even follow a proper diet, but at least they put a good intensity in their training. And speaking of training, this is the second factor to consider, but, like other factors, due to the extension of the topic, I will leave it to be addressed in the next posts.
In images 1, 2 and 3 you see, respectively, the difference in the increase of type 1, type 2 fibers and lean mass in individuals who had a higher density of androgen receptors (high responders, in gray) compared to individuals with lower density of receptors (low responders, blank) when both were submitted to resistance training.
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References:
1 - GARDNER, David G; SHOBACK, Dolores. Greenspan's Basic and Clinical Endocrinology. 9. ed. Porto Alegre: AMGH, 2013. p. 5-6.
2 - Morton RW, Sato K, Gallaugher MPB, Oikawa SY, McNicholas PD, Fujita S and Phillips SM (2018) Muscle Androgen Receptor Content but Not Systemic Hormones Is Associated With Resistance Training-Induced Skeletal Muscle Hypertrophy in Healthy, Young Men. Front Physiol. 9:1373. doi: 10.3389/fphys.2018.01373
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Images
The question, then, is: “the higher my testosterone levels, the greater my mass gain?”. And the answer is: Not exactly.
Through hormonal physiology, we know that a certain hormone only exerts its biological function after binding to its receptor (which can be located in various tissues of our organism) and, then, starting a series of metabolic reactions. Therefore, the amount of hormone that is still circulating in the plasma, identified through biochemical tests, is not yet bound to the receptor and, therefore, is not performing its expected function [1].
In the case of testosterone and the hypertrophy process, what we expect is that the hormone binds to the receptor located in the skeletal muscle and that, then, there is a signal to increase protein synthesis or prevent degradation. However, the acute increase in the levels of intramuscular testosterone and its derivatives does not predict gains in men who practice bodybuilding [2].
More important than circulating and intramuscular levels, what we must consider is the density of androgen receptors contained in skeletal muscle. That is, the more androgen receptors you express in your muscles, the greater the response to the hormone. This was demonstrated in 2018 in the study conducted by Morton and his colleagues. In summary, in this study, the researchers were able to conclude that the density of androgen receptors, and not hormones (testosterone and its derivatives) at the intramuscular level, influences the hypertrophy process in young men who practice bodybuilding.
So now the question is: What should I do to increase this androgen receptor density?
Well, about that, certainly the first most impacting factor is genetics. This explains when we see bodybuilders, without the use of anabolic steroids, with high physiological levels of testosterone and who do not have a greater volume of lean mass even when training and eating properly. At the same time, the opposite is true. There are men with relatively low levels of testosterone, but who have a physique that calls into question the use of steroids. Not to mention that, sometimes, the latter don't even follow a proper diet, but at least they put a good intensity in their training. And speaking of training, this is the second factor to consider, but, like other factors, due to the extension of the topic, I will leave it to be addressed in the next posts.
In images 1, 2 and 3 you see, respectively, the difference in the increase of type 1, type 2 fibers and lean mass in individuals who had a higher density of androgen receptors (high responders, in gray) compared to individuals with lower density of receptors (low responders, blank) when both were submitted to resistance training.
--
References:
1 - GARDNER, David G; SHOBACK, Dolores. Greenspan's Basic and Clinical Endocrinology. 9. ed. Porto Alegre: AMGH, 2013. p. 5-6.
2 - Morton RW, Sato K, Gallaugher MPB, Oikawa SY, McNicholas PD, Fujita S and Phillips SM (2018) Muscle Androgen Receptor Content but Not Systemic Hormones Is Associated With Resistance Training-Induced Skeletal Muscle Hypertrophy in Healthy, Young Men. Front Physiol. 9:1373. doi: 10.3389/fphys.2018.01373
--
Images
