What are the physiologic and clinical effects of testosterone?


That Other Guy
Testosterone is important for maintaining muscle mass and strength, bone mass, fat distribution, sex drive, and sperm production in men. Low testosterone associations include low energy, reduced strength, decreased cognitive function, lower libido, increased breast size, and depressed mood.

Symptoms of low testosterone (low libido, erectile dysfunction, osteoporosis or fracture, sleep disturbance, depressed mood, lethargy, or diminished physical performance) are nearly universal, especially in older men.

Zitzman et al12 and others suggest that the specific symptoms associated with hypogonadism develop at different total testosterone concentrations. Loss of vigor and libido may occur at approximately 350-430 ng/dL, whereas depression, disturbed sleep, lack of concentration, and diabetes are associated with total testosterone levels of approximately 230-290 ng/dL. Other hormones, including estrogen, may also influence pattern of symptoms.