MedicineNet.com
About Us | Privacy Policy | Site Map
March 15, 2010
MedicineNet home Picture Slideshows Diseases and conditions Symptoms and signs Procedures and tests Medications Picture Image Collection MedTerms medical dictionary Pet Health
Font Size
A
A
A


Low Testosterone

Medical Author: Benjamin C. Wedro, MD, FACEP, FAAEM
Medical Editors: Ruchi Mathur, MD, FRCP(C) and Melissa Conrad Stöppler, MD

Low Testosterone Symptoms

Low Testosterone Symptoms in Men & Women

Symptoms of low testosterone in males depends upon when the low levels occur. In men, low testosterone may lead to:

  • infertility,
  • decrease sexual function and desire,
  • erectile dysfunction (ED),
  • hair loss,
  • decreased muscle mass, and
  • osteoporosis.

Symptoms of low testosterone levels in women include:

  • hot flashes,
  • irritability,
  • loss of sexual desire,
  • sleep disturbances,
  • loss of muscle mass, and
  • decreased bone density (osteoporosis).

What is testosterone?

Testosterone is a steroid hormone which is made in the testes in males and in the ovaries in women (a minimal amount is also made in the adrenal glands). Testosterone has two major functions in the human body.

  1. Testosterone is needed to form and maintain the male sex organs and promote secondary male sex characteristics (in both men and women) such as voice deepening and hair growth patterns. This function is related to its androgenic properties.

  2. Testosterone is the facilitation of muscle growth as well as bone development and maintenance. This is a result of its anabolic properties.

Testosterone production is regulated by hormones released from the brain. The hypothalamus and pituitary gland located in the brain produce hormonal signals that ultimately result in the production of testosterone. The hypothalamus is located just above the brain stem, and among its many functions, it produces gonadotrophin releasing hormone (GRH). GRH then travels a short distance to the pituitary gland, which is located in the base of the brain, and stimulates this gland to release FSH (follicle stimulating hormone) and LH (luteinizing hormone). These hormones travel through the bloodstream to activate the sex organs in both men and women. Subsequently, these hormones have a role in regulating testosterone levels in the bloodstream.

The majority of testosterone circulates in the blood bound to a carrier protein (many hormones that are produced in one area and affect another area have a carrier protein that helps their travel through the bloodstream). In this case the carrier protein is called "sex hormone binding globulin," or SHBG. When testosterone is being carried by SHBG, it is considered "bound". Bound testosterone does not play an active role in the body; only the unbound or "free" testosterone is able to enter the different cells of the body and exert its androgenic and anabolic effects. Thus, anything that affects the function or the amount of SHBG can also affect the total circulating amount of active testosterone.

Picture of the endocrine system including the testes and ovaries

What is low testosterone?

The human body functions within a relatively narrow range of normal. When chemicals such as hormones fall outside those normal levels, there can be consequences that affect the body at a cellular, organ, or systemic (body-wide) level.

Blood tests used to measure testosterone are usually performed in the morning. Testosterone sampling is difficult since the levels normally tend to bounce around a fair bit during the course of the day. The normal value for total testosterone in males is 270-1070 ng/dl. However, this depends to some extent on the individual laboratory being used, and the range can vary as a result. In women, there is debate about the accuracy of testosterone measurements, because the circulating values are so much lower than in males and are harder to accurately measure.

With advancing age, in both men and women, the amount of testosterone the body produces gradually falls. Free testosterone levels can be measured and normal levels depend upon an individual's age. Interestingly, menopause itself does not seem to play a role in a reduction of testosterone levels in women beyond that of advancing age.



Next: What are the causes of low testosterone? »

Share | | | | | More

Low Testosterone

The MedicineNet physician editors ask:

What were the symptoms of your low testosterone levels?

Anonymously share your comment to help others. Patient Discussions FAQs
See 2 Viewer Comments

Submit Your Comment


Suggested Reading by Our Doctors
MedicineNet Doctors
  • esterified estrogens and methyltestosterone, Estratest, Estratest HS -
  • Chemotherapy - Get information on chemotherapy treatment for cancer, side effects of medications and how chemo works. Chemotherapy is a type of cancer treatment often given along with radiation therapy and surgery.
  • Tuberculosis - Read about tuberculosis (TB) treatment, diagnosis (skin test), transmission, cause (Mycobacterium) and symptoms. TB infection is a contagious disease that's easily spread.

Latest Medical News


Sex & Relationships

Get tips to boost your love life.


Are you Depressed? Take the Quiz

Your Guide to Symptoms & Signs: Pinpoint Your Pain



Low Testosterone

What is sarcoidosis?

Sarcoidosis is a disease that results from a specific type of inflammation of tissues of the body. It can appear in almost any body organ, but it starts most often in the lungs or lymph nodes.

The cause of sarcoidosis is unknown. The disease can appear suddenly and disappear. Or it can develop gradually and go on to produce symptoms that come and go, sometimes for a lifetime.

As sarcoidosis progresses, microscopic lumps of a specific form of inflammation, called granulomas, appear in the affected tissues. In the majority of cases, these granulomas clear up, either with or without treatment. In the few cases where the granulomas do not heal and disappear, the tissues tend to remain inflamed and become scarred (fibrotic).

Sarcoidosis was first identified over 100 years ago by two dermatologists working independently, Dr. Jonathan Hutchinson in England and Dr. Caesar Boeck in Norway. Sarcoidosis was o...

Read the Sarcoidosis article »











Health categories:

Slideshows | Diseases & Conditions | Symptoms & Signs | Procedures & Tests | Medications | Image Collection | Medical Dictionary | Pet Health

Popular health centers:

Allergies | Arthritis | Blood Pressure | Cancer | Chronic Pain | Cold & Flu | Diabetes | Digestion | Eyesight | Health & Living | Healthy Kids

Hearing & Ear | Heart | Infectious Disease | Men's Health | Mental Health | News & Views | Pregnancy | Sexual Health | Skin | Women's Health | More...

MedicineNet.com:

About Us | Newsletters | RSS Feeds | Privacy Policy | Site Map | WebMD® | Medscape® | eMedicine® | eMedicineHealth® | RxList®

This website is certified by Health On the Net Foundation. Click to verify. This site complies to the HONcode standard for trustworthy health information:
verify here.

©1996-2010 MedicineNet, Inc. All rights reserved. Notices and Legal Disclaimer.
MedicineNet does not provide medical advice, diagnosis or treatment. See additional information.