The key to masculinity and vitality is the human growth hormone that separates the boys from the men. It plays a vital role in the creation of muscle mass and strong bones. It contributes to deep voice and even sex drive. Low testosterone in men is known as hypogonadism. As a product of a modern world made for convenience the male body does not go through nearly as much rigorous activity. The lack of daily exercise contributes to the decrease in male testosterone. It can hit as early as the mid 20s and steadily decrease each subsequent year.
Researchers haven't unraveled the mystery of just how testosterone increases libido. It's normal for a man's sex drive to slowly decline from its peak in his teens and 20s, but libido varies widely between men. What one man might consider a low sex drive, another might not. Also, sex drive changes within each man over time and is affected by stress, sleep , and opportunities for sex. For these reasons, defining a "normal" sex drive is next to impossible. Usually, the man himself identifies a lack of sex drive as a problem. Other times, his partner may consider it to be an issue.
In general, Bhasin says, doctors should give more information to patients considering the treatments. For example, he says, "doctors don’t tell you that testosterone supplements may end up a long-term proposition." When men begin using a supplement, he explains, they typically lose the ability to create testosterone on their own. So if a health problem should arise that forces them to stop taking the supplements, it may take months or years to recover the ability to create adequate levels of testosterone naturally, during which time they may experience withdrawal symptoms like poor mood and low vitality.
“I find it very distressing that testosterone is used in middle-aged men — when we don’t know whether it’s even safe — for something that may be a normal physiologic adaptive mechanism to aging," he says.
Both experts agree that men with a history of heart attack or stroke should steer clear of testosterone supplements. They also agree that there are scenarios in which the benefits of testosterone therapy nearly always outweigh the risks, like hypogonadism, a disease in which the body produces little or no hormone due to poorly functioning testes or pituitary or hypothalamus glands.