Testosterone, the hormone responsible for creating male characteristics, mainly is produced by the testes. A small amount of testosterone comes from the adrenal glands. In puberty, testosterone stimulates the growth of pubic and facial hair, according to MedlinePlus, a service of the National Institutes of Health. It deepens the voice and causes muscles and bones to grow larger. As a hormone, testosterone affects the entire body. After reaching adulthood, a lack of testosterone affects a man's life in many ways.
Decreased Sexual Performance
A lack of testosterone can lead to erectile dysfunction, the inability to achieve or keep an erection firm enough for intercourse. Sexual arousal and erection are the result of a complex series of events involving hormones, nerves, blood vessels and attitude. A problem at any stage can result in ED. Low testosterone due to aging is a common cause of ED. Treatment for ED caused by low testosterone consists of testosterone supplementation by way of injections, oral pills, topical gels, patches or buccal medications. Buccal medications are small tablets placed in the mouth between the lip and the gum.
Lack of Sexual Arousal
Low levels of testosterone may lower sexual desire, according to the Journal of Endocrinology. Sexual arousal includes erection, sexual thoughts, motivation to engage in sexual experiences and the possibility of orgasm. In the healthy, middle-aged male, low testosterone levels cause a decrease in sexual arousal. In older men, low testosterone levels may cause a decrease in sexual arousal, but the mechanism of arousal is so complex, it is difficult to discern the exact cause in older men.
Loss of Muscle Mass
Low levels of testosterone in males may cause a loss of muscle mass. As a man ages and testosterone levels naturally decrease, the ability to retain muscle mass decreases. Testosterone plays a direct role in the building and maintenance of muscles, according to USC Health Magazine.
Mood Problems
Risk of depression increases substantially in men with low testosterone levels, according to Medscape.com. A 2004 study performed by the Western Australian Centre for Health and Ageing in Perth, Australia, found that low testosterone levels were more important in determining depression than age, obesity, poor health or education level. Men ages 71 to 89 took part in this study.
Increased Mortality Rates
Low testosterone levels increase mortality rates, according to Mesdcape.com. In a 2006 study on veterans conducted at the VA Puget Sound Health Care System in Seattle, Washington, Sally M. Shores, MD, found that mortality of men with normal testosterone was 20.1 percent and of men with low testosterone was 34.9 percent. The study excluded acute illness and those who died the first year of the study. The link between low testosterone and the direct causes of mortality was not discussed.
