Signs of low testosterone in men may include decreased sex drive, erectile dysfunction (ED), lowered sperm count or increased breast size. Men also may have symptoms similar to those seen during menopause in women – hot flashes, increased irritability, inability to concentrate and depression. Some men may have a prolonged and severe decrease in testosterone production. As a result, they may experience loss of body hair and reduced muscle mass, their bones may be more brittle and prone to fracture, and their testes may become smaller and softer. In younger men, low testosterone production may reduce the development of body and facial hair, muscle mass and genitals. In addition, their voices also may fail to deepen. Women may experience a decrease in sex drive, lack of energy, decreased “enjoyment of life”, and even depression.