Research debunks bodybuilding hormone myth

default-hero-image

New research from McMaster has found that exercise-related testosterone and growth hormone do not play an influential role in building muscle after weightlifting. The findings may mean that bodybuilders who look to manipulate those hormones through exercise routines are wasting their time.


New research from scientists at McMaster reveals exercise-related testosterone and  growth hormone do not play an influential role in building muscle after weightlifting,  despite conventional wisdom suggesting otherwise.

The findings indicate that bodybuilders who look to manipulate those hormones  through exercise routines are wasting their time.

In two separate studies, published in the Journal of Applied Physiology and the European Journal of Applied Physiology, researchers found anabolic hormones-long  thought to be essential for building a muscular frame-do not influence muscle protein  synthesis, the process that leads to bigger muscles.

“A popular mindset for weightlifters is that increased levels of hormones after exercise  play a key role in building muscle,” explains Daniel West, lead author of both studies  and a graduate student in the Department of Kinesiology at McMaster. “That is simply  not the case.”

In the first study, researchers examined the responses of both male and female  participants to intense leg exercise. Despite a 45-fold difference in testosterone  increase, men and women were able to make new muscle protein at exactly the same  rate.

“Since new muscle proteins eventually add up to muscle growth, this is an important  finding,” says West.

“While testosterone is definitely anabolic and promotes muscle growth in men and  women at high doses, such as those used during steroid abuse, our findings show that  naturally occurring levels of testosterone do not influence the rate of muscle protein  synthesis.”

In the second study, researchers analyzed the post-exercise hormonal responses of 56  young men, aged 18 to 30, who trained five days a week for 12 weeks in total.

The men experienced gains in muscle mass that ranged from virtually nothing to more  than 12 pounds, yet their levels of testosterone and growth hormone after exercise  showed no relationship to muscle growth or strength gain.

Surprisingly, the researchers noted that cortisol-considered to have the opposite effect  of anabolic hormones because it reduces protein synthesis and breaks down tissue-was  related to the gain in muscle mass.

“The idea that you can or should base entire exercise training programs on trying to  manipulate testosterone or growth hormone levels is false,” says Stuart Phillips, a  professor in the Department of Kinesiology. “There is simply no evidence to support this  concept.”

The research was funded in part by the Canadian Institutes of Health Research and the  Natural Sciences and Engineering Research Council of Canada.