Low Testosterone (Low-T)

An underproduction of testosterone causes low-T in men and women.

• Testosterone is a hormone required for male development and sexual function and is produced primarily in the testicles.
• Testosterone is responsible for building muscle and bone mass, sperm production, and sex drive.
• Testosterone influences male pattern fat distribution, bone density, and red blood cell production.
• In the normal developing male, testosterone peaks during early adulthood. Once you reach age 30, testosterone levels slowly decline by approximately 1% a year. This is a normal part of aging.

What are normal ranges or levels of testosterone in men?

The low limit of testosterone levels in men is about 300 nanograms per deciliter and the upper normal limit is approximately 1000-1200 ng/dl. A low level needs to be investigated further to distinguish it from normal aging.

• Low testosterone (low-T) is underproduction or lack of production of testosterone in men and women.
• Causes of low-T include chronic medical conditions such as diabetes, infections, obesity, or other hormonal conditions.
• Symptoms of low-T include:
  • Change in sleep patterns
  • Reduced sex drive (low libido)
  • Sexual dysfunction
  • Infertility
  • Emotional changes
  • Decreased strength
  • Weight gain
• Low-T testing includes linking symptoms with testosterone blood levels.
• Treatment options for low-T include different forms of testosterone replacement therapy.

Some of the conditions that can lead to a low level are:

• Obesity
• Diabetes (type 2)
• Chronic medical conditions (especially liver or kidney disease)
• Hormonal disorders
• Infections
• Medications (narcotics, chemotherapy)

It is important to distinguish between a normal decline of testosterone levels and hypogonadism.

Signs and symptoms of low testosterone include:

1. Change in sleep patterns: insomnia or sleep disturbances
2. Physical changes: increased body fat and reduced muscle bulk
3. Sexual changes: reduced sexual desires, sexual dysfunction, or infertility
4. Emotional changes: decreased motivations, depression
5. Worsening of sleep apnea
6. Worsening of congestive heart failure

Although testosterone therapy helps with hypogonadism, whether it helps in the reversal or slowing of normal effects of aging and lower testosterone levels is unclear. Several published research articles have conflicting results and more research is needed to make a final determination about the use of testosterone for healthy aging males.

The diagnosis of low-T is based on correlating a low blood level (300 ng/dl or below) with symptoms.

Most of the symptoms are very apparent (see previously), but some need to be further investigated (such as low bone density).

Treatment of low testosterone in hypogonadism is a fully accepted therapy. Treatment in older men is more controversial. Discuss your testosterone levels, symptoms, and side effects of treatment with your doctor to establish whether you should receive therapy and what form of therapy.

There are several ways that testosterone therapy can be administered:

• Transdermal (skin patch): Usually applied once a day (for example, Androderm). Tends to be clean and easy to apply. There is an available mouth patch that sticks to the upper gums and is applied twice daily.
• Gels: Applied directly to the skin and then absorbed through the skin (for example, AndroGel, and Axiron). Dosing is more difficult although these gels are available in single applications packages or premeasured pumps.
• Injections: Testosterone can be delivered by direct injection.
• Pellets: Pellets can be implanted into the soft tissue and release the testosterone.

Why no pills? Testosterone is available as a pill but some experts believe long-term oral delivery of testosterone can have negative effects on the liver. These other delivery methods bypass the liver (as they don't involve a pill being absorbed through the stomach/intestine) and go directly into the blood stream.

• Get enough sleep
• Keep a healthy weight
• Stay active

Possible side effects and risks of testosterone therapy for the normal aging male include:

• Stimulation of growth of the prostate (benign prostatic hypertrophy) and possible growth of existing prostate cancer
• Skin reactions
• Limiting sperm production and shrinkage of testicles
• Overproduction of red blood cells (which can contribute to a heart attack)
• Some studies have implicated testosterone in an increase in cardiovascular events.

The definite verdict on testosterone therapy is still out. Testosterone therapy is accepted as a treatment for hypogonadism, a clearly defined medical condition.

In older adults who have markedly decreased testosterone levels without significant symptoms or who have modestly decreased levels with significant symptoms, testosterone therapy should be considered after a discussion with your doctor about side effects and possible positive effects of therapy.

There is no clear proof that testosterone therapy is helpful in reversing any aspects of natural aging in males.