What is TRT

What Is TRT?

What is Testosterone Replacement Therapy?

Learn everything you need to know about ‘What is TRT’ and how Immortal Male can help with low testosterone.

Table of Contents


Are you or a loved one looking looking into testosterone replacement therapy but find yourself asking, “what is TRT?” Read our guide to learn about the TRT process and how to receive help today.

Testosterone is often incorrectly associated with negative behaviors, such as aggression, but the truth is that testosterone is a complex and essential tool for the human body. In males especially, testosterone is necessary for the growth and maintenance of masculine characteristics.


Testosterone is a hormone found in both men and women created from cholesterol in the body. In men, testosterone is the major sex hormone and has several vital functions, including:1

  • Maturation of sex organs (penis and testes)
  • Size and strength of muscles
  • Growth and strength of bones
  • Development of libido (sex drive)
  • Production of sperm

As men age, the amount of testosterone produced in the body begins to decline steadily.2 An estimated 25% of men experience low testosterone with increased age, with over one-third of men older than forty-five experiencing levels of testosterone lower than average.3

Testosterone: An Overview

What Is Testosterone Replacement Therapy (TRT)?

Testosterone replacement therapy is one of the available treatment options for low testosterone. TRT is the process of returning levels of testosterone in the body to a natural concentration through external sources of testosterone. It’s important for anyone considering low testosterone treatment options to learn about the advantages of testosterone replacement therapy and the issues it is intended to treat.


Low testosterone is common, causing many men to experience the symptoms of male testosterone deficiency, also known as hypogonadism.4 Testosterone replacement is an effective treatment for individuals who test for and show signs and symptoms of low testosterone or are professionally diagnosed with hypogonadism. As many as 2.8% of men aged forty years and older in the United States receive testosterone replacement therapy per year.5


Hypogonadism is an increasingly more common condition, affecting 20% to 40% of older men.6 When hypogonadism occurs in older men, it is often referred to as late onset hypogonadism (LOH) or andropause. Hypogonadism more prevalent in men with underlying conditions such as obesity, diabetes, asthma, prostatic disease, hypertension, and chronic obstructive pulmonary disease (COPD).6

In men, hypogonadism presents itself as the gonads or testes improperly functioning, thus inhibiting production of testosterone. Hypogonadism can also lead to improper sperm counts. An individual can either be born with hypogonadism, or experience it later in life, often as a result of injury or infection.

Who is Fit for Testosterone Replacement Therapy?

Testosterone replacement is intended for individuals who have been professionally diagnosed with hypogonadism. Diagnosing low testosterone requires a serum testosterone of less than 300 ng/mL and that the individual is experiencing the specific symptoms of low testosterone.7

Low Testosterone and Male Health

Signs of Low Testosterone Levels

Common signs and symptoms of low testosterone include:

  • Feeling more fatigued than usual
  • Feeling more irritable than usual
  • Erectile dysfunction
  • Decreased mood
  • Decreased sexual drive
  • Lower muscle mass
TRT Prescriptions Statistics

TYPES OF Testosterone Replacement Therapy

There is an array of testosterone replacement methods available, including tablets, injections, transdermal systems, pellets, and buccal preparations. The wide variety of TRT medicine delivery systems allows patients to achieve the benefits of testosterone therapy with a method they are comfortable using. A study from the National Library of Medicine found that patient satisfaction among injections (73%), pellets (70%), and gels (68%) were relatively similar, showing that multiple options yield positive results.8

A key part of learning about TRT is familiarizing oneself with the types of testosterone replacement therapy options. Popularly prescribed TRT delivery methods are discussed in detail below:

Testosterone Injections

Testosterone replacement therapy injections are administered as intramuscular injections, with doses occurring every one to two weeks.9 Administration of testosterone replacement therapy injections may occur independently at home or require visiting a provider for each dose. Selecting the best testosterone injection option requires a conversation between the patient and their provider to determine a treatment plan that meets the patient’s needs and expectations.

The benefits of testosterone therapy begin taking shape several months after the first injection. For the best testosterone injection results, the patient must stick to their schedule and maintain regular administration.9


Testosterone replacement therapy gel is a widely used and popular form of TRT medication. The gel is applied by the patient to the skin of the arms, torso, or thighs, making this a relatively easy type of testosterone to manage. Testosterone replacement therapy gel has shown to be a highly effective method for the management of symptoms of hypogonadism. When comparing testosterone gel vs. injection, it is important to note that the gel requires greater care from the patient to reduce opportunities for skin-to-skin transfer with others.9

Testosterone Patches

There is currently one testosterone patch available in the United States. The patch is an effective type of testosterone replacement therapy for men; however, one-third of men reported high rates of skin irritation. When comparing the testosterone patch vs. gel, the patch will protect patients from unintentional skin transfer, which can be desirable for patients with female partners or children.9

Implanted Pellets

Testosterone pellet implants are placed in the fat of the lower abdomen, buttocks, or thighs by a medical professional. This option requires visiting a provider’s office every three to six months for pellet renewal, as a sterile technique is needed for pellet insertion. A benefit of this method is that doses are infrequently delivered, which may be desirable for patients with busy or uncertain schedules. Furthermore, one study found that 86% of men were satisfied with this testosterone treatment method and experienced symptom improvement.9

Nasal Gel

Nasal gel availability is limited in clinical settings, as it has a high potential for nasal and gingival irritation and lacks comprehensive studies to confirm the safety of this testosterone delivery type. Nonetheless, two trials showed that 90% of patients achieved normal levels of serum testosterone after ninety days, indicating promise as a good option for patients who are unable to utilize the other types of testosterone offered.9

Oral Pills

Oral testosterone pills yield low serum testosterone concentrations, but studies are currently in progress to enhance their effectiveness.9 Patients must take oral pills with a fat-containing meal for this testosterone replacement method to receive its full benefits. Note that while oral pills are a safe option that offers continued patient monitoring, they can be potentially toxic to the liver.10

Bioidentical Hormone Therapy

Bioidentical hormone therapy involves the utilization of natural sources, typically plants, to create a chemically identical hormone. Delivering a chemically identical hormone to the body is generally considered safer than the alternative, synthetically designed hormone options. Bioidentical hormone therapy is a great choice for patients seeking the health benefits of TRT.

Testosterone Replacement Therapy: Overview of Options

Benefits of Testosterone Replacement Therapy

Men who undergo successful testosterone replacement therapy will find themselves with restored libido, energy levels, and erectile function. The benefits of testosterone therapy are described in greater detail below.

Improved Energy Level

Evidence supports that men professionally diagnosed with hypogonadism see improved energy levels and experience reduced fatigue after testosterone therapy.10

Boost in Mood

When an individual’s depression is related to low testosterone or stems from dissatisfaction due to symptoms of hypogonadism, evidence suggests that TRT can help alleviate depressive symptoms. In a meta-analysis of 1,890 men, patients who received testosterone replacement therapy reported a significant decrease in depressive symptoms compared to placebo.11

Further, a systematic literature review performed in 2020 supports TRT-related reduction of depressive symptoms in patients with clinically diagnosed cases of mild depression. However, the review found that TRT is not as impactful for men with major depressive disorder.12

In any case, major depressive symptoms should be addressed and treated by a professional psychologist. Testosterone replacement exists to treat the symptoms of hypogonadism; symptoms of depression alleviated by TRT treatment are an additional benefit that cannot be guaranteed for every patient.

Decreased Anxiety

Hypogonadism is associated with depression and anxiety. In hypogonadal men, multiple studies have shown that TRT improves mental health, including reducing symptoms of anxiety.13 It is important to remember that TRT is intended to alleviate the symptoms of hypogonadism and should not be used as a first-line method to treat anxiety. Moreover, anxiety not caused by low testosterone will likely not be reduced by testosterone therapy. Consulting a physician is the safest way to achieve optimal testosterone therapy results for mood-related concerns.13

Strength Increase

Studies have linked testosterone replacement to muscle strength improvements in middle-aged and older men. Among multiple studies, body strength and fat-free mass (FFM) increased with TRT three to five times more than with other therapies and placebo. More specifically, TRT resulted in a 5.7% increase in FFM and a 10% to 13% increase in body strength. Given that hypogonadism is associated with decreased strength, testosterone replacement therapy for men is an important option to consider, as preservation of mobility becomes more important in aging men.14

Muscle Gain

Another advantage of testosterone replacement therapy is muscle gain. One study found that men with low testosterone experienced increased muscle mass and decreased fat mass after six months of therapy. Further muscle gain can be achieved with exercise alongside treatment. Patients can work with their providers to maximize muscle gain throughout the treatment process.15

Sex Drive

One of the major health benefits of TRT is the improvement of libido and erectile function. Several studies provide evidence for restored libido in hypogonadal men taking testosterone replacement. Along with increased sex drive, men with mild to moderate erectile dysfunction as a result of hypogonadism experienced improved erectile function after beginning testosterone therapy.16

Better Bone Density

Testosterone is essential for the maintenance of bone mineral density in men. In a comprehensive review evaluating the impact of testosterone replacement methods on bone health, results showed that TRT helped prevent bone loss and acquire peak bone mass in hypogonadal men with osteoporosis and osteopenia.17
Hypogonadism Diagnostic Statistics

who Should Not Take TRT?

As with any medical treatment, individuals need to understand the potential risks and adverse side effects. The side effects of testosterone therapy are largely debated due to changing evidence in the scientific community. Potential, high-interest risks include cardiovascular events, the development of prostate cancer, and erythrocytosis. These risks have been evaluated in multiple study groups, but the available data is insufficient to determine the risk-to-benefit ratio of each potential side effect.18

In addition, eligibility or recommendation against TRT varies from person to person. Factors such as medical history, illness, and specific health concerns can affect how the body reacts to TRT, possibly resulting in adverse or enhanced side effects.

Individuals With Hematocrit > 50

Hematocrit (HCT) is the number of red blood cells in the blood. If an HCT test reveals too little or too few red blood cells, it can indicate a disease. Individuals with HCT levels greater than 50% are advised to consider treatment with testosterone replacement carefully. The long-term effects of testosterone therapy are associated with a higher risk of developing erythrocytosis, or high red blood cell count.19

Erythrocytosis may increase a patient’s likelihood of developing blood clots, which can cause thromboembolic events, such as pulmonary embolism or deep vein thrombosis, stroke, and heart attacks. Testosterone injections are associated with the highest risk of erythrocytosis, with an incidence rate of nearly 40%.19

Individuals With a History of Cancer

Anyone who has had cancer, specifically breast or prostate cancer, is advised to consult with a physician before seeking testosterone treatment. Current research has revealed conflicting evidence for the development of prostate cancer after beginning TRT.20

Since insufficient data is available for a definitive report on the risk of TRT-related cancer, most doctors recommend a conservative approach to testosterone prescriptions as a protective measure. Therefore, patients should talk about testosterone therapy with a provider who knows their history of cancer before taking any TRT treatment steps.20

Individuals With a Prostate-Specific Antigen > 4 ng/mL

Prostate-specific antigen (PSA) tests are used to monitor the risk of developing or progressing prostate cancer. In general, higher levels of PSA are indicators of prostate cancer.20For men undergoing testosterone replacement therapy, recent studies have shown that TRT is not associated with an increased PSA level.21

Nevertheless, evidence on the long-term effects of testosterone therapy has been conflicting over the years, so the safest route for patients with elevated PSA is to seek alternatives to TRT.22

Individuals With Untreated Hyperlipidemia

Hyperlipidemia refers to disorders of elevated lipid levels in the body and is a serious risk factor for the development of vascular and cardiovascular diseases.23 Although current research has not elucidated whether or not testosterone therapy contributes to an increased risk of experiencing a cardiovascular event, there is evidence indicating a positive relationship between testosterone, cardiovascular disease, and cholesterol.24 Thus, it is advised for medical professionals to exercise caution when prescribing testosterone to individuals with untreated hyperlipidemia.

Other Issues to Bring Up to a Physician

Additionally, men who have untreated obstructive sleep apnea, are planning fertility, or have experienced a cardiovascular event (e.g., myocardial infarction, heart attack) within the past six months should consider alternative low testosterone treatment options to TRT.
Male Aging Study Statistics

How Do I Know if I Have Low Testosterone?

Low testosterone should only be diagnosed by medical professionals. Diagnostic criteria for hypogonadism include experiencing specific symptoms, such as low libido, fatigue, erectile dysfunction, and decreased muscle mass, and testing with a low testosterone serum count by an accredited laboratory.

Hypogonadism is characterized by many symptoms and can frequently be mistaken for or overlap with other conditions, such as depression or sleep apnea, making diagnosis difficult.3 So, any person searching for relief from hypogonadism-related symptoms should seek care from a team of highly educated individuals for a proper diagnosis.

Blood Test for Low Testosterone

The blood test for low testosterone measures the amount of testosterone present in serum. Low testosterone is diagnosed at a serum testosterone concentration of less than 300 ng/dL.25

Diagnostic Criteria for Hypogonadism

Hypogonadism can only be accurately diagnosed with laboratory findings of low total serum testosterone levels. For healthy men, total serum testosterone should be greater than 300 ng/dL, usually above 500 ng/dL. For those with low testosterone, the criteria for a hypogonadism diagnosis include total serum testosterone levels of less than 300 ng/dL in combination with at least one symptom of hypogonadism, such as decreased libido, depression, and loss of muscle mass and strength.25

Total Serum Testosterone Level Statistics

What Is the Process of TRT?

Testosterone replacement therapy begins with a professional diagnosis of hypogonadism. As mentioned earlier, a hypogonadism diagnosis requires a serum testosterone concentration of less than 300 ng/dL and evidence of at least one symptom of hypogonadism.25 Individuals experiencing the symptoms of hypogonadism but do not meet diagnostic criteria are advised to speak with a primary care provider for alternative treatments for the symptoms.

What to Expect in Treatment?

After a professional diagnosis, patients will speak with a physician to determine the treatment plan that works best for their individual needs. It is always important to seek out medical providers who place patient care and safety at the forefront of treatment plan development.

How Long Do I Have to Take Testosterone Replacement Therapy?

Around age thirty, testosterone levels begin to decline by 1.6% on average each year.26 For men with hypogonadism, this decline can have a more significant effect on the body, causing more prominent and life-changing symptoms. Since the body is no longer adequately producing testosterone, continued TRT treatment is the only way to feel the benefits of restoring testosterone levels in the body. TRT may be discontinued at any time, but patients will not continue to receive the desired testosterone replacement therapy results.

Start With the At-Home Hormone Test From Immortal Male

Immortal Male offers a comprehensive testosterone replacement therapy program that accounts for the whole health and well-being of each patient. From the start, patients are connected with a team of medical professionals ready to help through every step of the process. 

Starting testosterone replacement therapy for men with Immortal Male is simple. Everything begins with the At-Home Hormone Test Kit, which can be ordered from the Immortal Male website

Personalized Diagnosis and Treatment

At Immortal Male, patient well-being comes first. For a personalized diagnosis and treatment plan, the process begins with a complete hormone panel tested by an accredited laboratory and access to a team of licensed physicians. The hormone test provides physicians with a baseline to help them develop a treatment protocol to yield optimal results.

On-Going Treatment and Optimization

Patients are treated to the very best in personalized care throughout the entire treatment process. The More Life Membership offers a customized treatment program with the appropriate medications to optimize and maintain overall health. Patients have access to highly qualified professionals prepared to answer question, “what is TRT?” and adjust treatment plans when the need arises. 

Concierge Team

The concierge team is available to answer questions and concerns throughout the TRT treatment process. 

Prescription Sent Home

When the More Life Membership package arrives, patients can breathe a sigh of relief. Longevity, quality of life, and whole-body health start now. With the Immortal Male treatment program, restoration and fulfillment can finally be achieved.  

If you want to learn more about what TRT is, contact Immortal Male today.

Journal of Clinical Endocrinology and Metabolism

Stephanie T. Page, John K. Amory, F. DuBois Bowman, Bradley D. Anawalt, Alvin M. Matsumoto, William J. Bremner, J. Lisa Tenover, Exogenous Testosterone (T) Alone or with Finasteride Increases Physical Performance, Grip Strength, and Lean Body Mass in Older Men with Low Serum T, The Journal of Clinical Endocrinology & Metabolism, Volume 90, Issue 3, 1 March 2005, Pages 1502–1510, https://doi.org/10.1210/jc.2004-1933B)