Testosterone is an important hormone in both genders but is the primary sex hormone in men.  Hormones are chemicals that are derived from cholesterol and made by glands in the body. Once made, the hormones circulate in the bloodstream and regulate all body functions.

Testosterone is very important to men and women.  It is primarily secreted from the ovaries of females and testicles of males, but small amounts are secreted by the adrenal glands.

The amount of testosterone in the body is monitored by the hypothalamus, a tiny structure in the brain that has the central role of controlling hormones and our autonomic nervous system. When the body senses that more testosterone is needed, the hypothalamus sends a signal to the pituitary gland, the master hormone gland,  which then releases a hormone called luteinizing hormone (LH) which tells the testicles or ovaries that  more testosterone is needed.


Testosterone is the most important male sex hormone.  As males mature, testosterone causes:
•    The penis and testicles to grow larger
•    Facial and pubic hair to grow
•    A teenage boy’s voice to become deeper
•    Boys to grow taller
•    The muscles to get bigger and stronger
•    The production of sperm cells
•    An interest in sex

You can see the placement of the testicles and prostate in the illustration below.

While the average adult male should be producing about ten times more testosterone than the average adult female, there is a wide variance in testosterone production and an array of symptoms that can result from lower or higher testosterone output.

For most men, after the age of 35, the amount of testosterone normally starts to decrease.  In many men the level reduces to the point that men start to experience many adverse effects. This is called Andropause –the male equivalent to Menopause in women.

In women, approximately one-half of their testosterone is produced in their ovaries.  The testosterone level for a postmenopausal woman is about half the normal level for a healthy, nonpregnant woman. And a pregnant woman will have three to four times the amount of testosterone compared to a healthy, nonpregnant woman.

In men and women, about 40% of the testosterone is bound tightly to a protein called “sex hormone binding globulin” and is not available to be used by the body.  About 58% is bound to albumin (water soluble proteins that occur in egg white, milk, blood and other meat and vegetables) and is available to the body for use. The remaining 2% of testosterone circulates freely in the blood. The level of testosterone in a male’s body changes throughout the day.  It is highest in the morning.


According to the National Institute of Health, at least five million men suffer from low testosterone.  There are a number of medical conditions that can cause low testosterone.

Here are some of the symptoms:
•    Decreased sex drive or libido
•    Impotence or erectile dysfunction in men
•    Lowered sperm count in men
•    Increased breast size in men
•    Hot flashes
•    Increased irritability
•    Anger
•    Fatigue
•    Inability to concentrate
•    Depression
•    Loss of body hair in men
•    Loss of muscle
•    Decreased bone density leading to more bone fractures
•    Smaller and softer male testicles


Sometimes this is caused by damage to the cells of the testicles. This damage can be a result of
•    Accidents
•    Inflammation of the testicles
•    Testicular cancer
•    Radiation therapy or chemotherapy used to treat testicular cancer
•    Diseases affecting the hypothalamus and the pituitary glands such as:
•    Cancer
•    Inflammation
•    Autoimmune diseases
•    Using anabolic steroids
•    Using opioids and narcotics like:
•    Heroin
•    Morphine
•    OxyContin
•    Oxycodone
•    Hydrocodone
•    Vicodin
•    Percocet
•    Using other psychotropic drugs


In women, low levels of testosterone are frequently caused by:
•    An underactive pituitary gland
•    Addison’s disease (when the adrenal glands don’t produce adequate cortisol and aldosterone)
•    Loss of ovary function through disease or surgery
•    Radiation therapy
•    Diseases affecting the hypothalamus and the pituitary glands such as:
•    Cancer
•    Inflammation
•    Autoimmune diseases
•    Using anabolic steroids
•    Using opioids and narcotics like:
•    Heroin
•    Morphine
•    OxyContin
•    Oxycodone
•    Hydrocodone
•    Vicodin
•    Percocet
•    Using other psychotropic drugs


The American Association of Clinical Endocrinologists defines hypogonadism (lower than normal production of testosterone) as a condition where the free testosterone level is lower than normal.

Blood tests are used to determine the testosterone levels.  Since testosterone levels are higher in the morning, this is considered the best time to do the blood test.  Many doctors consider that normal testosterone levels for men are between 250 to 1,000 nanograms per deciliter (ng/dl).  In women, the normal levels are between 30 to 95 nanograms per deciliter (ng/dl)).

Some doctors believe that they should test for total testosterone and free testosterone using the free androgen index.  The value is determined by dividing the total testosterone by the amount of sex hormone binding globulin.  According to Dr. Malcolm Carruthers in his book Maximizing Manhood: Male Menopause:Restoring Vitality and Virility,

“This key ration should normally be in the range of 0.70-1.00 and andropausal symptoms are almost always present when the FAI (free androgen index) falls below 50 per cent.”

Most doctors believe that even with low testosterone levels, no replacement treatment is appropriate in men with prostate cancer until the prostate cancer is addressed and handled.


While there are many side effects of opioid use, there are an increasing number of studies showing that opioid use often lowers testosterone.  In clinical observation studies of those abusing opiates, Dr. Brent Agin has found several teenagers with testosterone levels under 100 and men under the age of 35 with levels under 200. Teens should have levels well above 500.

In the Sonoma Medicine Magazine: Controversies in Therapeutics, Volume 60, Number 4 – Fall 2009, Are We Making Pain Patients Worse?, by Andrea Rubinstein, MD, Dr. Rubinstein stated:

“Several recent studies have looked at the effect of opioids on the endocrine system, particularly testosterone levels in men. One study found that 74% of male opioid users had testosterone levels below 300. This data is surprising but hardly new.

“In an 1839 report on the tea trade in India, the trader Charles Alexander Bruce observed that, “Opium has kept, and does now keep down the population: the women have fewer children than those of other countries … the feeble opium smokers of Assam … are more effeminate than women.

“In the pain clinic at Kaiser Santa Rosa, I routinely screen all men on opioids for hypogonadism. Over 50% are below 300, and it is not uncommon to have men with testosterone levels less than 100. Among men on methadone in our population, 80% are hypogonadal.

“The endocrine effect of opioids occurs in women as well, although it is not as clear-cut or as easy to diagnose. Symptoms may include depression and sexual dysfunction and may involve dysmenorrhea.   Unfortunately, none of these symptoms are specific to opioid use.

“Physicians with significant numbers of patients on long-term opioid therapy will probably see pre-menopausal women with some or all of these symptoms, so it is important to consider opioid-induced endocrinopathy as part of the differential diagnosis.”

In Volume 1, Issue 9 of the 2005 Patient Rounds, Dr. Nathaniel Katz, stated,

”In summary, a number of lines of evidence – including preclinical studies, heroin addiction, methadone maintenance – indicate that intrathecal (something placed under the brain or spinal cord) and oral opioids in both cancer and non-cancer pain suppress testosterone secretion, primarily via central mechanisms (although a peripheral component may be important as well). This suppression appears to have important clinical consequences, including decreased sexual desire and performance, potentially increased anxiety and depression, and reduced quality of life. Some studies have found a dose-response effect, with increasing testosterone suppression with increasing opioid doses.”

Another study was discussed in the August 28, 2006 issue of the Archives of Internal Medicine.  Molly M. Shores, MD, from the VA Puget Sound Health Care System in Seattle, Washington, wrote,

“Low serum testosterone is a common condition in aging associated with decreased muscle mass and insulin resistance… Testosterone levels also decrease with acute and chronic illnesses and with medications such as glucocorticoids and opiates.”


In the December 14, 2009 edition of CNS Spectrums, researchers found that low-dose transdermal testosterone augmentation therapy improves depression severity in women.

More studies are being done on the effect of SSRI’s, antipsychotics and benzodiazepines on testosterone.  Most of these studies are directed to the effect of these drugs on the body’s creation of prolactin.  Prolactin is a hormone believed to provide feelings of sexual gratification and in women affects the production of breast milk.

Increased amounts of prolactin have also been linked to a reduction in the production of testosterone.  In the December of 2004 Journal of Clinical Psychiatry, entitled Effects of Psychiatric Disorders and Psychotropic Medications on Prolactin and Bone Metabolism, the authors  

“…searched PubMed for original articles and reviews published between 1976 and 2004 that described changes in bone metabolism in psychiatric disorders and examined prolactin elevations with neuroleptic medications.”

The study concluded that these drugs not only affected loss of bone density but pointed out that they often increased the amount of prolactin which can lead to hypogonadism.

In  December, 2003, Dr. Michael Gitlin, Department of Psychiatry, UCLA School of Medicine, released a report entitled Sexual Dysfunction With Psychotropic Drugs.  Dr. Gitlin discussed the extent to which psychotropic medications, especially antidepressants and antipsychotics, cause sexual side effects.

Obviously, one of the leading contributors to sexual side effects is the reduction of testosterone levels.


Like any other medical treatment, testosterone therapy should only be started after a medical doctor has evaluated a patient.   There are risks of testosterone therapy if not monitored and appropriately administered.

Here are some of them:
•    Sleep apnea (a sleep disorder in which breathing repeatedly stops and starts)
•    Elevated red blood cells
•    Acne or other skin reactions
•    Stimulation of noncancerous growth of the prostate (benign prostatic hypertrophy).
•    Possibly stimulate growth of existing prostate cancer
•    Enlarged breasts
•    Limited sperm production
•    Testicle shrinkage


The importance of adequate testosterone levels has not been adequately understood by many patients and their doctors.  If you are having any of the symptoms referred to in this article, it is highly recommended that you have your testosterone levels checked and evaluated by a medical doctor that is educated on the treatment of hormone deficiencies.