In male humans, testosterone plays a key role in the development of male reproductive tissues such as the testes and prostate, as well as promoting secondary sexual characteristics. Testosterone is the hormone responsible for the development of male sexual characteristics. Hormones are chemical messengers that trigger necessary changes in the body. It is a type of androgen produced primarily by the testicles in cells called the Leydig cells.

In men, testosterone is thought to regulate several functions alongside sperm production. These include:

  • sex drive
  • bone mass
  • fat distribution
  • muscle size and strength
  • red blood cell production
  • 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
  • Sperm production
  • Without adequate amounts of testosterone, men become infertile. This is because testosterone assists the development of mature sperm.

testosterone levels

Women have testosterone too but in much smaller amounts than in men. The brain and pituitary gland, a small gland at the base of the brain, control the production of testosterone by the testes. From there, testosterone moves through our blood to do its work. Your testosterone levels change from hour to hour. They tend to be highest in the morning and lowest at night. Testosterone levels are highest by age 20 to 30 and slowly go down after age 30 to 35. For many reasons, testosterone can become—and stay—too low. Less often, testosterone levels can become too high. When this hormone is not in balance, health problems can result. One of the treatments used for low testosterone is Testosterone Replacement Therapy.


“Low Testosterone can occur as young as your 30’s but much more in your 50’s. Your body will let you know if you are willing to listen and that is your opportunity to fix it. When it comes to testosterone products, you lucky guys will be happy to know that you can benefit not only an erection, but an improved metabolism, a healthier heart, and better brain function.”


What is Testosterone Replacement Therapy?

Testosterone Replacement Therapy

Testosterone Replacement Therapy is primarily used to treat low testosterone (T) levels, which can occur with age or as a result of a medical condition. It is used to help treat people with abnormally low levels of testosterone. These abnormally low levels usually affect normal body functions, which can contribute to decreased muscle mass and a lower sex drive, among other effects. Testosterone Replacement Therapy is approved to treat male hypogonadism (low testosterone or “Low T”), a condition in which the body fails to make enough hormones because of a problem with the testicles, pituitary gland, or brain. It is also known as Androgen Replacement Therapy.

For this treatment, testosterone medication is prescribed. This medication is testosterone in pills, patches, and gel that you apply to your skin and liquid that you inject into your body. It helps to increase your body’s overall testosterone level and eliminate or decrease certain symptoms of low testosterone. But it’s becoming increasingly popular for non-medical uses, including:

  • enhancing sexual performance
  • achieving higher energy levels
  • building muscle mass for bodybuilding

Only men with symptoms of low testosterone and blood levels that confirm this as the cause of symptoms should consider testosterone replacement. Talking with your doctor is the only way to know if testosterone therapy is right for you. Symptoms of low testosterone include:

low sex drive

  • Low sex drive (libido)
  • Erectile dysfunction
  • Fatigue and poor energy level
  • Decreased muscle mass
  • Body and facial hair loss
  • Difficulty concentrating
  • Depression
  • Irritability
  • Low sense of well-being

Testosterone replacement therapy is available in several forms. All can improve testosterone levels:

  • Skin patch (transdermal): Androderm is a skin patch worn on the arm or upper body. It’s applied once a day.
  • Gels: AndroGel and Testim come in packets of clear testosterone gel. Testosterone is absorbed directly through the skin when you apply the gel once a day. AndroGel, Axiron, and Fortesta also come in a pump that delivers the amount of testosterone prescribed by your doctor. Natesto is a gel applied inside the nose.
  • Mouth patch: Striant is a tablet that sticks to the upper gums above the incisor, the tooth just to the right or left of the two front teeth. Applied twice a day, it continuously releases testosterone into the blood through the oral tissues.
  • Injections and implants: Testosterone can also be injected directly into the muscles, or implanted as pellets in the soft tissues. Your body slowly absorbs testosterone into the bloodstream.
  • Subcutaneous pellets: Your doctor inserts these under your skin every 3 to 6 months. They are very convenient once they’re put in, but they require minor surgery for each dose.

Some of the benefits of Testosterone Replacement Therapy include:


  • Increased energy;
  • Increased bone density;
  • Reduced risk of obesity, diabetes, and metabolic syndrome;
  • Reduced risk of cardiovascular disease;
  • Reduced risk of osteoporosis;
  • Reduced body fat;
  • Reduced risk of anemia; and
  • Increased lean body mass and muscle strength.

Increased energy


  • Increased libido;
  • Increased sexual enjoyment;
  • Increased satisfaction with erections; and
  • Increased sexual activity.



  • Improved mood and sense of wellbeing; and
  • Improved cognition and memory function.


How Does Testosterone Replacement Therapy Work?

Testosterone replacement therapy is a treatment in which additional testosterone is added to a man’s body (e.g. by injecting medicines that contain testosterone), to increase the concentration of testosterone in his body. It is used to treat hypogonadism, a condition characterized by low levels of testosterone in the blood and clinical symptoms of testosterone deficiency. Testosterone replacement therapy aims to increase blood testosterone concentrations to normal levels. In doing so, it can also restore the man’s sex drive and expression of male sex characteristics (e.g. deep voice, body hair).

Testosterone replacement therapy

Improvements in blood testosterone levels and libido generally occur within the first week of treatment, and other benefits usually occur within two months. It is important to note that testosterone replacement therapy typically induces a strong placebo effect in the initial stages of therapy. This means that many men who have been treated with testosterone notice an improvement (e.g. better sex drive), not because the testosterone-containing medication has improved their testosterone concentrations, but because of the psychological effect of taking it. In short, some men think testosterone therapy is working and then feel better, even though the treatment does not work. This may lead to confusion and dissatisfaction as the placebo effect of treatment diminishes.

As the causes of testosterone deficiency are typically irreversible, testosterone replacement therapy is usually lifelong. Men who use testosterone replacement therapy will be monitored throughout their treatment to assess their response. To assess the man’s response to treatment, levels of testosterone in his blood are usually measured three months after the start of treatment. Levels of luteinizing hormone (LH) may also be measured three to six months after treatment starts, as low levels of LH indicate that the treatment is effective.

injecting medicines that contain testosterone

If blood tests show that testosterone replacement therapy has failed to adequately increase concentrations of testosterone in the man’s blood, hypogonadism may not be the cause of the symptoms. In these cases, testosterone replacement therapy will be stopped and the doctor will start treating other conditions that may contribute to testosterone deficiency.

A doctor will monitor changes to symptoms of testosterone deficiency and side effects of the treatment. This monitoring usually occurs three and six months after treatment commences and annually thereafter. A doctor will typically examine a man for signs of:

  • Edema
  • Breast growth
  • Sleep apnea
  • Lower urinary tract disorders
  • Low bone mineral density.

 “The American Sexual Society of North America and the American Urological Society recommends a range of testosterone levels to be somewhere between 300 to 950. It is recommend3d to restore your testosterone levels to a normal range with 400 to 500 being optimal. This optimal range will solve your energy levels, metabolism problems, and general wellbeing. Testosterone has been shown to increase mental acuity, concentration, sense of well-being, and happiness.”



What are the Side Effects of Testosterone Replacement Therapy?

Testosterone replacement therapy side effects most often include rash, itching, or irritation at the site where the testosterone is applied. However, there is also evidence of a possible increased risk of heart attack or stroke associated with testosterone use. Experts emphasize that the benefits and risks of long-term testosterone therapy are unknown because large clinical trials haven’t yet been done.

There are a few health conditions that experts believe testosterone therapy can worsen:

  • Benign prostatic hypertrophy (BPH): The prostate grows naturally under the stimulation of testosterone. For many men, their prostates grow larger as they age, squeezing the tube carrying urine (urethra). The result is difficulty urinating. This condition, benign prostatic hypertrophy, can be made worse by testosterone therapy.
  • Prostate cancer: Testosterone can stimulate prostate cancer to grow. Most experts recommend screening for prostate cancer before starting testosterone replacement. Men with prostate cancer or elevated prostate-specific antigen (PSA) should probably avoid testosterone treatment.
  • Sleep apnea: This condition can be worsened by testosterone replacement. It may be difficult for men to detect this themselves, but their sleeping partner can often tell. A sleep study (polysomnography) may be needed to make the diagnosis.
  • Blood clots: The FDA requires that testosterone replacement products carry a warning about the risk of blood clots in veins. This could increase the risk of deep vein thrombosis and pulmonary embolism, a potentially life-threatening clot that occurs in the lungs. Products already carried a warning about the risk of blood clots due to polycythemia, an abnormal rise in the number of red blood cells that sometimes occurs with testosterone treatment. Now the warning is more general to include men who don’t have polycythemia.

Blood clots

  • Congestive heart failure: Men with severe congestive heart failure should usually not take testosterone replacement, as it can worsen the condition.

Some other side effects include:

  • chest pain
  • difficulty breathing
  • speech difficulties
  • polycythemia vera
  • lowered HDL (“good”) cholesterol
  • swelling in the hands or legs
  • acne or similar skin breakouts
  • deep vein thrombosis
  • pulmonary embolism
  • Oily skin
  • Mild fluid retention
  • Stimulation of prostate tissue, with perhaps some increased urination symptoms such as a decreased stream or frequency
  • Increased risk of developing prostate abnormalities
  • Breast enlargement
  • Decreased testicular size
  • Increased aggression and mood swings
  • May increase risk of heart attack and stroke
  • Changes in cholesterol and lipid levels
  • Increase in red blood cell count
  • The decrease in sperm count, producing infertility (especially in younger men)
  • Increase in PSA

TRT has long been a treatment option for people with hypogonadism or conditions associated with reduced T production. But its benefits for those without an underlying condition aren’t as clear, despite all the hype. Talk to your doctor before you take any T supplements or medications. They can help you determine whether your goals with TRT are safe and realistic. It’s also important to be monitored by a medical professional as you take T supplements to note any unwanted symptoms or side effects that may occur during treatment.

 In her fabulous book, I MARRIED A DICK DOCTOR, MEDELINE ZECH RUIZ, talks about the various issues related to men in a compassionate and understandable language. She gives the reader an insight into these problems arising from low testosterone and their solutions.


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