Testosterone is a male sex hormone. This hormone is what makes males appear male. The responsibilities of testosterone include producing sperm, growing facial and body hair, building muscle and maintaining a man’s libido. The testes in the scrotum produce testosterone and the brain and the pituitary tumor control the amount produced. Medical conditions, injury, steroid use and increased age can cause the body to produce lower levels of testosterone. Recognizing the signs and symptoms of low testosterone, also called hypogonadism, is important to recognize so testosterone replacement therapy can begin to improve the symptoms.

Change in Libido

The first sign many males may notice when experiencing low levels of testosterone is a change in sex drive. A decrease in the interest of sexual intercourse is a symptom of hypogonadism, according to the Mayo Clinic 1. Testosterone replacement therapy may increase the libido again.

Low Sperm Count

One of the responsibilities of this hormone includes producing sperm. A lower level of sperm production occurs with decreased levels of testosterone production. This lowered sperm count causes infertility.

Erectile Dysfunction

Males with low testosterone may also experience an inability to get a full erection or to maintain one. This condition is also referred to as erectile dysfunction or impotence. Taking medications to treat the erectile dysfunction, without treating the low levels of testosterone, may not have an effect on the ability to have an erection.

Enlarged Breasts

Gynecomastia is the development of breast tissue in males. With low levels of testosterone production, men may begin to develop breasts.

Loss of Hair

Men have more body hair and facial hair growth than women. Testosterone production increases this amount of hair. A decrease in the levels causes males to lose this hair. Young males going through puberty with a decreased level of testosterone may not experience a growth in facial or body hair. They may also have an increased amount of hair on the arms and legs.

Decreased Muscle Tone

Muscle mass and tone usually decreases as testosterone levels decrease. Muscle weakness may also occur. Young males have difficulty developing muscle mass, according to the Mayo Clinic.

Small Testes

Hypogonadism causes the testes to shrink because they are no longer used for the production of testosterone. Pubescent males may experience decreased growth in the testicles and the penis.


Decreased testosterone levels causes a decrease in bone mass, called osteoporosis. Symptoms of osteoporosis include an increased risk of bone fractures, especially in the hip and spine.