Target Pituitary

What is Low Testosterone?

Low testosterone ("low T") in men has many causes, including pituitary dysfunction. Low testosterone results in loss of libido (sex drive), and decreased sexual function (erectile dysfunction (ED) or impotence) and can result in infertility.

Hypogonadism Information

Target Pituitary

  • What are the symptoms?

    Early symptoms of low testosterone in men include low libido (sex drive). As levels become very low, sexual dysfunction (also called "erectile dysfunction (ED)" or "impotence") often develops. Other signs and symptoms of low testosterone may include depression, fatigue, osteoporosis, loss of muscle mass, an increase in abdominal fat, development of breast tissue (gynecomastia) and infertility.

    Symptoms of low testosterone in women may include low libido (sex drive), sexual dysfunction, fatigue, loss of muscle mass, an increase in body fat and bone loss.

  • What are the causes?

    There are many causes of low testosterone. These can be differentiated with hormone testing. Pituitary dysfunction is one cause of low testosterone and can result from compression of the pituitary gland by a large pituitary tumor. In addition, excess hormone secretion by a pituitary tumor can cause low testosterone either directly or indirectly. For example, elevated prolactin, cortisol or GH levels can cause low testosterone. Testosterone levels normalize with treatment of the tumor in some, but not all, cases. There are other causes of low testosterone that are not related to pituitary tumors. These include anabolic steroid use (for body building or athletic enhancement), obesity, depression, and testicular failure.

  • Complications

    The complications of low testosterone in men include infertility, sexual dysfunction, osteoporosis, loss of muscle mass, depression and fatigue.

  • Preparing for your appointment
    Write down questions to ask your doctor.

    You're likely to start by seeing your family doctor or a general practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to an endocrinologist, a doctor who specializes in endocrine (hormonal) disorders.

    Special Instructions (If available, please bring):

    • Copies of your medical records/discharge summary/physician notes.
    • A copy of your MRI or CT on a CD.
    • A copy of your lab reports.
    • Bring any medications you are taking with you to your appointment.
    • Please make sure your MGH registration is accurate and up-to-date.

    Our clinic assistants will help you update your hospital registration and insurance information.

    Thank you.

  • How is low testosterone diagnosed?

    Testosterone levels can be measured directly. An endocrinologist can test for causes of low testosterone, including elevated prolactin levels. Sometimes other blood tests are indicated to make the diagnosis or determine the cause, including free testosterone, sex hormone binding globulin, leutinizing hormone (LH) or evaluation for Cushing's disease or acromegaly.

  • How is low testosterone treated?

    If the underlying cause of the low testosterone can be determined and corrected, testosterone levels often rise to normal levels. Medical treatment to lower prolactin levels from a prolactinoma often results in normalization of testosterone level. In addition, resection of large nonfunctioning pituitary tumors that are causing low testosteorne by compressing the pituitary gland results in restoration of normal testosterone levels in approximately 50% of cases. Cure of acromegaly or Cushing's disease also often results in normalization of testosterone levels. In patients for whom the cause cannot be determined or addressed, testosterone replacement therapy can be prescribed by an endocrinologist with expertise in this area. There are a number of different preparations available, including gels, creams, patches, and injections. Your endocrinologist can discuss the pros and cons of the different options with you. S/he will also check lab results to make sure it is safe to prescribe the medication and that your testosterone levels on the medication are appropriate. If bone density does not improve when testosterone has been normalized, additional medications may be necessary.

    There are no FDA-approved testosterone preparations for women, who make 10 to 20 times less testosterone than men and therefore need much lower replacement doses than men.

  • What research is being done on low testosterone?

    Research is ongoing in the Neuroendocrine Unit on the effects of low testosterone and testosterone treatment in both men and women.