Testosterone

Testosterone is a hormone produced primarily in the testicles. Testosterone helps maintain men’s sex drive, red blood cell production, muscle strength and mass, fat distribution, moods and more.

Testosterone levels generally peak during adolescence and early adulthood. As you age, your testosterone level gradually declines — typically about 1% a year after age 30 or 40. For older men, it’s important to determine if a low testosterone level is present via blood work. Even after receiving testosterone treatment, it is extremely important to recheck blood work and testosterone levels quarterly.

Adolescent boys with too little testosterone may not experience normal masculinization. For example, the genitals may not enlarge, facial and body hair may be scant and the voice may not deepen normally.

Signals sent from the brain to the pituitary gland found at the base of the brain control the production of testosterone in men. The pituitary gland then relays signals to the testes to produce testosterone. A “feedback loop” via neurotransmitters closely regulates the amount of hormones in the blood. When testosterone levels rise too high, the brain sends signals to the pituitary to reduce production. Oftentimes as men age, a decrease in testosterone production may cause symptoms of decreased sex drive, mood swings, decreased energy, fat gain, muscle loss, hair loss and brain fog.