Dr. Rodwick, HIV AIDS, transgender, hepatitis C, Clearwater, FL, AAHIVM, WPATH, testosterone, Sculptra

Low testosterone facts

  • Testosterone is produced by the testes in males and ovaries in females. The testes are under the hormonal control of the hypothalamus and pituitary in the brain and make testosterone in response to stimulation by FSH and LH.
  • Primary hypogonadism occurs because of the inability of the testes to produce testosterone.
  • Causes of secondary and tertiary hypogonadism are due to a variety of illnesses or diseases that affect the hypothalamus-pituitary-gonadal axis.
  • Symptoms of low testosterone depend upon when in the life cycle it occurs.
  • Osteoporosis and loss of muscle mass are significant complications of low testosterone.
  • In the United States, testosterone replacement therapy is available as an FDA-approved treatment in men only. It may be administered by injection, patch or gel, implanted pellets, or gum and cheek putty.

What is testosterone?

Testosterone is an anabolic-androgenic 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 majority of testosterone circulates in the blood bound to a carrier protein (a hormone is produced in one are of the body and has its effect on another area. Often a carrier protein assists the hormone 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.

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.

As people age, the amount of testosterone the body produces gradually falls in both men and women. Free testosterone levels can be measured and normal levels depend upon an individual's age.

Low testosterone levels may be caused by a number of factors. For example – there may be a problem at the level of the hypothalamus or pituitary to produce appropriate amounts of LH and FSH to stimulate testosterone production. Another possibility is that the organs that make testosterone do not function normally or are not able to respond to stimulation by the brain. Also, as mentioned, changes in SHBG can affect for the amount of testosterone that is available to exert its effects.

Some common causes of hypogonadism or failure of the gonads (the medical term for the sex organs, or testes and ovaries) may include the following:

Testosterone effects on the body:











  • Aging: Testosterone levels gradually decrease with aging. Usually, enough testosterone is manufactured to allow for adequate bodily functions, but there is some research that suggests that lower testosterone levels can result in a variety of medical problems such as bone and muscle loss, and erectile dysfunction.
  • HIV and AIDS may also cause inflammation of both the hypothalamus and pituitary.
  • Illegal use of anabolic steroids, for example in athletes and body builders, can cause hypogonadism and low testosterone levels.

It should be noted that obesity also can be a cause of low testosterone. While it can be associated with other causes, obesity specifically enhances the conversion of testosterone to estrogen. This is a naturally occurring process in both men and women, and this conversion occurs predominantly in fat cells. In the case of obesity, the large amount of fat cells enhances this process, and testosterone levels may fall due to excessive conversion to estrogen.

What are the symptoms of low testosterone?

Low testosterone symptoms in males

In adulthood, low testosterone may lead to decreased sexual function and desire,infertility, and erectile dysfunction. Loss of hair, decreased muscle mass, and osteoporosis, or decreased bone density, may occur.

Low testosterone symptoms in females

While low testosterone is usually thought of as a male disease, low levels may occur in women and cause significant issues. Symptoms may includehot flashes, irritability, loss of sexual desire (decreased libido), and sleep disturbances. Loss of muscle mass, decreased bone density (osteoporosis), and loss of body hair may also be seen.

What is the treatment for low testosterone?

The initial consideration for treating low testosterone is to find the underlying cause and address that issue.

While the testosterone levels fall with aging, there is no evidence that this is an abnormal condition requiring treatment.  However, research results are inconclusive, and studies measuring the effect of testosterone in men age 60 to 80 found no benefit in mental or physical function.

Treatment of low testosterone in men

In men, low testosterone levels in the body can be supplemented by hormone replacement with testosterone. Testosterone replacement therapy can be prescribed as an intramuscular injection usually given on a biweekly basis, as a patch or gel placed on the skin, or as putty that is applied to the gums of the mouth. It is also available as pellets that are inserted under the skin and release testosterone slowly over several months. Each of the treatments has its risks and benefits. The decision as to which form of testosterone to use depends upon the clinical situation. Discussions between the patient and health care practitioner often helps decide which medication to use.

Treatment of low testosterone in women

In women, in the United States there are currently no preparations that are FDA approved for testosterone replacement. (Estratest, a combination of estrogen and methyltestosterone that was formerly available, was discontinued by the manufacturer in the spring of 2009.

Some doctors will advise women to cut the patches for men into smaller sizes, or to use the gel in smaller doses; however, the accuracy of these methods is questionable, as is the safety.

Testosterone levels

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