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Low Testosterone

Testosterone is a steroid hormone from the androgen group. It is the principal male sex hormone and the "original" anabolic steroid.

The latest development in testosterone use appears to be a reprise of the anti-aging claims. A number of physicians, supported by pharmaceutical manufacturers, are popularizing the concept that the testosterone decline of aging (which they term the "andropause") is unnecessary and can be treated. Many endocrinologists suspect that this issue will play out like post-menopausal estrogen replacement: use will increase until large trials demonstrate (1) the benefits are much less dramatic or assured than when treating deficiency, and (2) a higher incidence of side effects will occur associated with this type of use.

Testosterone is often administered to transmen (female-to-male transsexual and transgenderpeople) as part of the hormone replacement therapy.

symptoms of low testosterone

low testosterone symptoms include:

  • general weakness of the body
  • lack of physical strength
  • lack of mental clarity

Low testosterone sympoms may be best described by looking at what people have used testosterone for.

These include:

  • Infertility
  • lack of libido or erectile dysfunction
  • osteoporosis
  • penile enlargement
  • height growth
  • bone marrow stimulation and reversal of anemia
  • and even appetite stimulation.

In general, androgens promote protein synthesis and growth of those tissues with androgen receptors. Testosterone effects can be classified as virilizing and anabolic effects, although the distinction is somewhat artificial, as many of the effects can be considered both. Virilizing effects include growth of the penis, formation of the scrotum, and deepening of the voice, as well as beard and torso hair. Many of these fall into the category of secondary sex characteristics. When they occur to an unwanted degree in women they are termed "virilization" or "masculinization". Anabolic effects include growth of muscle mass and strength, increased bone density and strength, and stimulation of height growth and bone maturation.

Testosterone effects can also be classified by the age of usual occurrence. For postnatal effects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone.

Most of the prenatal androgen effects occur between 7 and 12 weeks of gestation.

  • Genital virilization (midline fusion, phallic urethra, scrotal thinning and rugation, phallic enlargement)
  • Development of prostate and seminal vesicles

Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4-6 months of age. The function of this rise in humans is unknown. It has been speculated that "brain masculinization" is occurring since no significant changes have been identified in other parts of the body.

Early postnatal effects are the first visible effects of rising androgen levels in childhood, and occur in both boys and girls in puberty.

  • Adult-type body odor
  • Increased oiliness of skin and hair, acne
  • Pubarche (appearance of pubic hair)
  • Axillary hair
  • Growth spurt, accelerated bone maturation
  • Fine upper lip and sideburn hair

Advanced postnatal effects begin to occur when androgen has been higher than normal adult female levels for months or years. In males these are normal late pubertal effects, and only occur in women after prolonged periods of excessive levels of free testosterone in the blood.

  • Phallic enlargement (including clitoromegaly)
  • Increased libido and erection frequency
  • Pubic hair extends to thighs and up toward umbilicus
  • Facial hair (sideburns, beard, mustache)
  • Chest hair, periareolar hair, perianal hair
  • Increased muscle strength and mass
  • Deepening of voice
  • Growth of spermatogenic tissue in testes, male fertility
  • Growth of jaw and remodelling of facial bone contours
  • Completion of bone maturation and termination of growth (via estradiol metabolites)

"Adult testosterone effects" are important in adult males, and may decline as testosterone levels decline in the later decades of adult life.

  • Maintenance of muscle mass and strength
  • Maintenance of bone density and strength
  • Libido and erection frequency
  • Mental and physical energy

testosterone replacement therapy

Testosterone was first isolated from a bull in 1935. There have been many pharmaceutical forms over the years. Forms of testosterone for human administration currently available in North America include testosterone cypionate and enanthate in oil for injection, methyltestosterone tablets for oral ingestion, and skin patches and a gel preparation for transdermal absorption. A buccal oral preparation is also available. In the pipeline are a "roll on" delivery method and a nasal spray. Both are under development.

The original and primary therapeutic use of testosterone is for replacement in males who lack it (hypogonadism). When used for this purpose, the benefits of body development, physical strength, and mental energy can be dramatic and side effects rare.

However, over the years, as with every hormone, testosterone or other anabolic steroids has also been given for many other conditions and purposes besides replacement, with variable success but higher rates of side effects or problems. Examples include infertility, lack of libido or erectile dysfunction, osteoporosis, penile enlargement, height growth, bone marrow stimulation and reversal of anemia, and even appetite stimulation. By the late 1940s testosterone was being touted as an anti-aging wonder drug (e.g., see Paul de Kruif's The Male Hormone) in exactly the same way that growth hormone is being described today.

Anabolic steroids have also been taken to enhance muscle development, strength, or endurance. After a series of scandals and publicity in the 1980s (such as Ben Johnson's improved performance at the 1988 Summer Olympics), prohibitions of anabolic steroid use were renewed or strengthened by many sports organizations, and it was made a "controlled substance" by the United States Congress.

Posted by Staff at May 18, 2005 1:40 AM

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Comments Archive

What is the connection, if any between low T and depression?

Posted by: steve at August 28, 2006 8:07 PM

I need testosterone replacement therapy

Posted by: JB at September 5, 2006 5:29 AM