Significance

• About 13 percent of American men have low testosterone levels, and fewer than 10 percent of these men seek treatment.
  
  

Symptoms

• Common symptoms of low testosterone in men include low libido, erectile dysfunction, low sperm count and decreased fertility, hot flashes, irritability, memory difficulties, poor concentration and depression.
  
  

Causes

• Causes of low testosterone in men include aging, damage to or removal of the testes, thyroid disease, genetic conditions and other medical issues. Opioids, steroids and other medications also affect testosterone levels.
  
  

Medications

• Testosterone is available in pill form, injections, patches and as a gel. Side effects may include prostate growth, difficulty with urination, sleep apnea, exacerbation of existing heart disease, problems with respiratory functioning and persistent erection.
  
  

Misconceptions

• High testosterone does not cause baldness or prostate cancer and is not dangerous when monitored by appropriate medical providers.