TESTOSTERONE

 WHAT IS TESTOSTERONE ?


Testosterone is the primary sex hormone and anabolic steroid in males.[3] In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.[4] In addition, testosterone in both sexes is involved in health and well-being, including moods, behavior, and in the prevention of osteoporosis.[5][6] Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss.

Testosterone is a steroid from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites.[7] It exerts its action through binding to and activation of the androgen receptor.[7] In humans and most other vertebrates, testosterone is secreted primarily by the testicles of males (see Biosynthesis) and, to a lesser extent, the ovaries of females. On average, in adult males, levels of testosterone are about seven to eight times as great as in adult females.[8] As the metabolism of testosterone in males is more pronounced, the daily production is about 20 times greater in men.[9][10] Females are also more sensitive to the hormone.[11]


In addition to its role as a natural hormone, testosterone is used as a medication in the treatment of hypogonadism in men and breast cancer in women.[12] Since testosterone levels decrease as men age, testosterone is sometimes used in older men to counteract this deficiency. It is also used illicitly to enhance physique and performance, for instance in athletes.[13] The World Anti-Doping Agency is listing it as S1 Anabolic agent substance "prohibited at all times".[14]


Testosterone's Role

Testosterone is the major sex hormone in males and plays a number of important roles, such as:

  • The development of the penis and testes
  • The deepening of the voice during puberty
  • The appearance of facial and pubic hair starting at puberty; later in life, it may play a role in balding
  • Muscle size and strength
  • Bone growth and strength
  • Sex drive (libido)
  • Sperm production

Adolescent boys with too little testosterone may not experience normal masculinization. For example, the genitals may not enlarge, facial and body hair may be scant and the voice may not deepen normally.

Testosterone may also help maintain normal mood. There may be other important functions of this hormone that have not yet been discovered.

Signals sent from the brain to the pituitary gland at the base of the brain control the production of testosterone in men. The pituitary gland then relays signals to the testes to produce testosterone. A "feedback loop" closely regulates the amount of hormone in the blood. When testosterone levels rise too high, the brain sends signals to the pituitary to reduce production.

If you thought testosterone was only important in men, you'd be mistaken. Testosterone is produced in the ovaries and adrenal gland. It's one of several androgens (male sex hormones) in females. These hormones are thought to have important effects on:

  • Ovarian function
  • Bone strength
  • Sexual behavior, including normal libido (although evidence is not conclusive)

The proper balance between testosterone (along with other androgens) and estrogen is important for the ovaries to work normally. While the specifics are uncertain, it's possible that androgens also play an important role in normal brain function (including mood, sex drive and cognitive function).

LOW TESTOSTERONE LEVEL (Low T)

 The American Urology Association (AUA) considers low blood testosterone or male hypogonadism to be less than 300 nanograms per deciliter (ng/dL) for adults.

However, some researchers and healthcare providers disagree with this and feel that levels below 250 ng/dL are low. Providers also take symptoms into consideration when diagnosing low testosterone.

Male hypogonadism is a medical condition that can affect people with testicles at any age from birth through adulthood.

Low testosterone is more likely to affect people who:

What are the symptoms of low testosterone?

Symptoms of low testosterone can vary considerably, particularly by age.

Symptoms that highly suggest low testosterone in adults assigned male at birth include:

Other symptoms of low testosterone in adults AMAB include:

Symptoms of low testosterone in children

Low testosterone before or during puberty for children assigned male at birth can result in:

  • Slowed growth in height, but their arms and legs may continue to grow out of proportion with the rest of their body.
  • Reduced development of pubic hair.
  • Reduced growth of their penis and testicles.
  • Less voice deepening.
  • Lower-than-normal strength and endurance.        

WHAT ARE THE CAUSES OF LOW T ?

There are several possible causes of low testosterone. The two types of male hypogonadism are:

  • Primary hypogonadism (testicular disorder).
  • Secondary hypogonadism (pituitary/hypothalamus dysfunction).

Causes of primary and secondary hypogonadism are also divided into either congenital (at birth) or acquired (developed later in childhood or adulthood).

Causes of primary male hypogonadism

Primary hypogonadism happens when something is wrong with your testicles that doesn’t allow them to make normal levels of testosterone.

Another name for primary hypogonadism is hypergonadotropic hypogonadism. In this type, your pituitary gland produces more luteinizing hormone (LH) and follicle-stimulating hormone (FSH) (known as gonadotropins) in response to low testosterone levels. The high levels of these hormones would normally tell your testicles to produce more testosterone and sperm. However, if you have damaged (most commonly related to prior chemotherapy) or missing testicles, they can’t respond to the increased levels of gonadotropins. As a result, your testicles make too little or no testosterone and sperm.

Sometimes in primary hypogonadism testosterone levels are within the normal range and gonadotropins are high. Your specialist will help you understand if you need treatment, even with normal testosterone levels.

Congenital conditions that affect your testicles and can lead to primary hypogonadism include:

  • Absence of testicles at birth (anorchia).
  • Undescended testicles (cryptorchidism).
  • Leydig cell hypoplasia (underdevelopment of Leydig cells in your testicles).
  • Klinefelter’s syndrome (a genetic condition in which people AMAB are born with an extra X chromosome: XXY instead of XY).
  • Noonan syndrome (a rare genetic condition that can cause delayed puberty, undescended testicles or infertility).
  • Myotonic dystrophy (part of a group of inherited disorders called muscular dystrophies).

Acquired conditions that affect your testicles and can lead to primary hypogonadism include:

Causes of secondary male hypogonadism

Conditions that affect how your hypothalamus and/or pituitary gland cause secondary hypogonadism. This is known as hypogonadotropic hypogonadism because there are low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Those low levels cause decreased testosterone and sperm production.

Congenital conditions that can lead to secondary hypogonadism include:

  • Isolated hypogonadotropic hypogonadism (a condition that causes low levels of gonadotropin-releasing hormone from birth).
  • Kallmann syndrome (a rare genetic condition that causes loss of the development of nerve cells in your hypothalamus that produce gonadotrophin-releasing hormone. It can also cause a lack of smell.).
  • Prader-Willi syndrome (a rare genetic multisystem disorder than can cause hypothalamus dysfunction).

Acquired conditions that can lead to secondary hypogonadism include:

Late-onset hypogonadism (LOH) is a type of secondary male hypogonadism that results from normal aging. As males age they have a deterioration of hypothalamic-pituitary function and Leydig cell function that decrease testosterone and/or sperm production.

LOH and low testosterone are more common in people AMAB who have Type 2 diabetes, overweight and/or obesity.

In one study, 30% of people AMAB who were overweight had low testosterone, compared to only 6% of those with weight in the normal range. In another study, 25% of people AMAB with Type 2 diabetes had low testosterone, compared to 13% of those without diabetes.

DIAGNOSIS AND TESTS

How is low testosterone diagnosed?

If you have signs and symptoms of low testosterone, a healthcare provider will perform a physical exam. They’ll also ask questions about your medical history, medications you take or have taken, smoking history and any symptoms you currently have. Blood tests may be ordered.

To make a diagnosis, a provider will consider your specific signs, symptoms and any blood test results.

What tests will be done to diagnose low testosterone?

The following tests can help confirm low testosterone and determine the cause:

  • Total testosterone level blood test: This test usually requires two sample collections between 8 a.m. and 10 a.m., when testosterone levels should be at their highest. If you’re sick or have recently been sick, it’s important to tell your provider. Acute illness may cause a falsely low result.
  • Luteinizing hormone (LH) blood test: This test can help determine if the cause of low testosterone is an issue with your pituitary gland.
  • Prolactin blood test: High prolactin levels may be a sign of pituitary gland issues or tumors.

MANAGEMENT AND TREATMENT

How is low testosterone treated?

Healthcare providers treat low testosterone (male hypogonadism) with testosterone replacement therapy. Testosterone replacement therapy has several different forms, including:

  • Testosterone skin gels: You apply the gel every day to clean, dry skin as directed. It’s important that you don’t transfer the gel to another person through skin-to-skin contact. Testosterone skin gels are one of the most common forms of treatment in the U.S.
  • Intramuscular testosterone injections: You or a provider can administer the injections into a muscle every 1 to 2 weeks. Providers can administer long-acting testosterone by injection every 10 weeks. There are also subcutaneous injection options.
  • Testosterone patches: You apply these patches every day to your skin as directed. You usually have to rotate their location to avoid skin reactions.
  • Testosterone pellets: A specialist implants these pellets under your skin every three to six months. The pellets provide consistent and long-term testosterone dosages.
  • Buccal testosterone tablets: These are sticky pills that you apply to your gums twice a day. The testosterone absorbs quickly into your bloodstream through your gums.
  • Testosterone nasal gel: You apply a testosterone gel by applying it into each nostril three times a day.
  • Oral testosterone: A pill form of testosterone called undecanoate is available for people with low testosterone due to specific medical conditions, such as Klinefelter syndrome or tumors that have damaged their pituitary gland.

You may not be able to receive testosterone replacement therapy if you have a history of the following:

What are the side effects of testosterone replacement therapy?

The side effects of testosterone replacement therapy include:

  • Acne or oily skin.
  • Swelling in your ankles caused by mild fluid retention.
  • Stimulation of the prostate, which can cause urinary symptoms such as difficulty peeing.
  • Breast enlargement or tenderness.
  • Worsening of sleep apnea.
  • Smaller testicles.
  • Skin irritation (if you use topical testosterone replacement).

Laboratory abnormalities that can occur with testosterone replacement therapy include:

  • Increase in prostate-specific antigen (PSA).
  • Increase in red blood cell count.
  • Decrease in sperm count, producing infertility (inability to have children), which is especially important in younger people who want to have biological children.

PREVENTION

Can low testosterone be prevented?

Healthcare providers and medical researchers don’t know how to prevent low testosterone from genetic conditions or damage to your testicles, hypothalamus or pituitary gland.

Lifestyle habits that may help keep testosterone levels normal include:

  • Eating a healthy diet.
  • Exercise.
  • Weight management.
  • Avoiding excessive use of alcohol and drugs.

OUTLOOK / PROGNOSIS

What can I expect if I have low testosterone (male hypogonadism)?

There’s no one-time fix for low testosterone. However, consistent hormone replacement therapy helps improve sex drive, ease symptoms of depression and increase energy levels for many people assigned male at birth (AMAB) experiencing low testosterone. Treatment may also boost muscle mass and bone density.

The mortality of people AMAB with testosterone deficiency is significantly higher than among people AMAB with normal testosterone levels. But, it is unclear whether replacing testosterone to a normal level reduces that increased mortality. Treatment is largely focused on the treatment of symptoms, not the specific testosterone level.

For congenital hypogonadism in children assigned male at birth, testosterone replacement therapy often helps prevent problems related to delayed puberty.

LIVING WITH

When should I see my healthcare provider about low testosterone?

If you’re taking hormone replacement therapy, regular follow-up appointments with a healthcare provider are important.

If you’re experiencing symptoms of low testosterone, such as a decrease in sex drive and hot flashes, talk to a healthcare provider. They will evaluate you and may order blood tests.

If your child assigned male at birth isn’t showing signs of puberty by the age of 14, talk to their pediatrician.

A note from Cleveland Clinic

Many people shrug off the symptoms associated with low testosterone as an unpleasant part of getting older. But you should address symptoms that interfere with your quality of life. If you’re noticing bothersome signs of low testosterone, see a provider and discuss your options for treatment.


TESTOSTERONE AS A STEROID DRUG

As men age their bodies are changing – their testosterone levels begin to dwindle, they experience muscle loss, mood swings, and a decrease in sex drive. What if there was a way to fix it? A way to reverse the effects of aging? When it comes to your health, there is almost no right or wrong way to do something if you want to achieve your ideal results. Hormone replacement therapy (HRT), like testosterone replacement therapy, might be the answer you are seeking when it comes to your health. It is important to employ a skilled professional to help you determine the best treatment plan and pick out the best form of testosterone to maximize your health goals and the benefits to your quality of life. Below are four types of injectable testosterone replacement therapy. Talk to a health professional about which one is right for you.

TYPES OF INJECTABLE TESTOSTERONE

➕ TESTOSTERONE ACETATE

➕TESTOSTERONE CYPIONATE

➕TESTOSTERONE ENANTHATE

➕TESTOSTERONE PROPIONATE

➕TESTOSTERONE SUSPENSION

➕ METHYL TESTOSTERONE


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