Testosterone (androgen) is a hormone.  Hormones are powerful chemicals that help keep our bodies working normally.  The term hormone is derived from the Greek word, hormo, which means to set in motion.  And that’s precisely what hormones do.  They stimulate, regulate, and control the function of various tissues and organs.  Made by specialized groups of cells within structures called glands, hormones are involved in almost every biological process, including sexual reproduction, growth, metabolism, and immune function.  These glands, including the pituitary, thyroid, adrenals, ovaries and testes, release various hormones into the body as needed.  

The principal male hormone and an anabolic steroid, testosterone is mainly produced in the male testes and female ovaries, with very small amounts  also secreted by the adrenal glands.  The Leydig cells also produce two other androgens that are of lesser potency and are made in smaller quantities.  In both males and females, it plays key roles in health and well-being.  Examples of its benefits could include:  enhanced libido, improved energy, strengthened immune function, protection against osteoporosis, building of lean muscle, improved sexual performance, enhanced sex drive, improved mood, better memory, lower cholesterol, protection against heart disease, reduced body fat, lower blood pressure, fewer wrinkles, less cellulite, protection against muscle atrophy, improved kidney function, accelerated wound healing, better bone density, and reduced stress levels. 

Testosterone production declines naturally with age, and in men, testosterone begins to decline at about age 25.  Low testosterone may result from disease or damage to the hypothalamus, pituitary gland, or testicles that inhibit hormone secretion and testosterone production.  Testosterone has a number of effects on muscles, bones, the central nervous system, bone marrow, the prostate, and sexual function.  It regulates the normal growth and development of the male sex organs, and promotes other male characteristics such as body hair, muscle mass, and a deeper voice.  Depending on age, insufficient testosterone production can lead to low sex drive, little to no interest in sex, erectile dysfunction, memory loss, irritability, poor stress reactions, weight gain, low metabolism, poor bone development, underdeveloped genitalia, diminished virility, tiredness, and muscle loss.   On average, the adult male body produces about twenty to thirty times the amount of testosterone that an adult female's body does.  However, the decline in testosterone production as men age is not as dramatic as the drop in women's estrogen production with the onset of menopause.  Even so, testosterone decline is a serious issue for many older men.  Among other problems, declining testosterone production is strongly associated with impotency and libido problems.  Top