It’s an increasingly popular idea: “boosting” testosterone with diet tweaks – increasing foods rich in zinc and magnesium – hoping to build muscle faster. But the reality is more nuanced.
Testosterone is an androgen hormone that plays a key role in development, particularly in boys during puberty. Its effect on muscle isn’t simply about how much of it you have, but how your body responds to it.
“There are two key factors,” says Prof Leigh Breen, a muscle physiology specialist from the University of Leicester. “The amount of testosterone in your system, and the number of androgen receptors in your muscles.” These act like docking sites, allowing the hormone to exert its effects on muscle mass. The number you have is largely determined by genetics, but how well they work can be influenced by lifestyle factors such as exercise.
For most people, natural variations in testosterone don’t make much difference to muscle mass. “For most of our adult life, natural fluctuations, or changes we see with exercise and diet, are subtle,” Breen says.
Testosterone does have a clear impact at the extremes. The most obvious example is anabolic steroid use. These drugs flood the body with testosterone at levels far beyond what would occur naturally. “The effect on muscle mass is significant,” says Breen. “People have been reported to gain muscle even without training.”
At the other end of the spectrum are medical conditions that drastically reduce testosterone, such as hypogonadism in older men. Severely low levels are associated with muscle loss and weakness, which is why some people are prescribed testosterone replacement therapy (TRT).
But, for most of us, testosterone operates within a relatively narrow range. Building muscle still comes down to the fundamentals: consistent training, adequate nutrition and time.
