Testosterone TRT Tests

What are the Best Testosterone TRT Tests?

Testosterone is synthesized from cholesterol, which, in spite of its bad reputation, is an essential biochemical building block for many hormones and nervous-system molecules. It is the hormone responsible for normal growth and development and maintenance of male sex characteristics. It also affects lean body mass, mood and sexual function in both males and females. It is the primary androgenic (responsible for masculine characteristics) and anabolic (muscle building) hormone.

How is Testosterone Produced in the Body?

Testosterone is produced by the testicles in males and by the ovaries in females, with small amounts also produced by the adrenal glands in both genders. Its production and secretion are regulated by other hormones in a hormonal cascade.

 The hormonal and reproductive function of the testicles (gonads) is regulated through interactions among the hypothalamus, the pituitary gland, and the gonads (commonly known as the hypothalamic-pituitary-gonadal axis [HPGA]). The three glands communicate through a cascade of hormones and a self-regulating feedback loop that controls the generation of each hormone. Release of gonadotropin-releasing hormone (GnRH) from the hypothalamus regulates secretion of other hormones (gonadotropins) that influence the testicles by way of the pituitary. GnRH controls the secretion of two gonadotropin hormones- luteinizing hormone (LH) and follicle-stimulating hormone (FSH)- by the anterior pituitary. Luteinizing hormone regulates the production and secretion of testosterone through the Leydig cells of the testes, while FSH stimulates the production of sperm.

When someone is found to have low testosterone blood levels this is known as “hypogonadism” There are several types of hypogonadism:

  • Primary hypogonadism is a hypergonadotropic condition (higher than normal levels of LH and FSH). This occurs when the testicles fail to produce sufficient levels of testosterone to suppress production of LH and FSH. As a result, LH and FSH levels are elevated while testosterone levels are decreased. The pituitary gland tries to increase testosterone at no avail even after increasing LH and FSH.
  • Secondary hypogonadism results from hypothalamic or pituitary dysfunction. It is characterized by disruption of central components of the HPGA resulting in decreased levels of GnRH, LH, or FSH. In this type of hypogonadism, low levels of LH do not allow for the proper stimulation of the production of testosterone by the testes.
  • Mixed hypogonadism results from a combination of primary and secondary causes. The most common cause of mixed hypogonadism is late-onset hypogonadism, which occurs with aging. This is associated with osteoporosis, decreased lean body mass, reduced cognition, fatigue and impairment of libido and erectile function. Other causes of mixed hypogonadism include alcoholism, diseases (such as uremia, liver failure, AIDS, and sickle cell disease), street drugs/alcohol, and medications like corticosteroid steroids used for inflammatory conditions. It should be noted that high levels of cortisol (hypercortisolism), resulting from either the use of anti-inflammatory steroids or physical causes, could lead to hypogonadism.

Is Testosterone Converted into Other Hormones?

 Testosterone can convert into other hormones and metabolites. The process in which testosterone is converted into estrogen (a female hormone) by the aromatase enzyme is known as “aromatization”. About 0.3-0.4 % of testosterone aromatizes to estradiol. Males with high body fat, aging males, males taking certain medications, males with sex chromosome genetic conditions such as Klinefelter's Syndrome or males with a genetic disposition to having higher than normal amounts of aromatase may experience higher conversion of testosterone into estrogen. Estrogen blood levels are usually measured by detecting estradiol, the main estrogen in humans.

Estrogen is an especially important hormone for men at the right concentration. It plays an important role in bone, hair, skin, and brain health as well as other functions in men.

Another metabolite of testosterone is dihydrotestosterone (DHT). About 10% of testosterone converts to DHT via the 5 alpha reductase enzyme. DHT has a positive effect on sexual desire but increases the production of excess skin oil and acne. So, it is important to monitor and determine the proper dosage of testosterone so that estradiol and DHT are kept within reference ranges needed for healthy body function as well as to prevent unwanted side effects of TRT.

About 2 percent of the testosterone in the body is active.  This “free testosterone” is not attached to binding proteins that would prevent it from interacting with its receptor.

 About 40 percent of the body’s testosterone is attached to albumin. This is a protein that can release the hormone as the need for it arises in the body. Free testosterone plus testosterone attached to albumin are referred to as “bioavailable testosterone”.

In a healthy young male, about 60 percent of his testosterone is attached to sex hormone binding globulin (SHBG). Hormones bound to SHBG cannot be used by the body and lose their anabolic effect.  As males grow older or if illness is present, SHBG sweeps up more and more testosterone, lowering free testosterone and its benefits.

Total testosterone is the sum of bioavailable testosterone and testosterone bound to SHBG. Measuring just the total testosterone in the blood may not provide the whole picture and let you know how much “active” or usable testosterone you have.

What is low testosterone?

The normal levels of combined bound and free testosterone in male bodies can range anywhere from 350 to 1,100 ng/dL (nanograms per deciliter). Levels will vary with age and individual factors. It is useful to also measure the level of free testosterone as this may be more indicative of how hormone therapy is progressing. Levels of free testosterone can range between 1 and 5 percent of the total testosterone count, with about 2 percent considered an optimal level.

Higher than normal testosterone (i.e., above 1,100 ng/dL of total testosterone) can cause decreases in the good cholesterol (high density lipoprotein [HDL]), increases in red blood cells (hematocrit- a factor that can increase blood viscosity and cardiovascular risks), and water retention among other side effects. Like everything in life, balance is key. Too much of a good thing can be detrimental.

Proper monitoring by an experienced physician is extremely important to ensure optimal levels of testosterone, to maximize benefits and to minimize side effects.

What Are the Symptoms of Low Testosterone?

As mentioned previously, hypogonadism is the medical term for the condition in males that is caused when the body is not producing sufficient amounts of testosterone. What most people do not realize is that in addition to sexual desire, testosterone also affects lean body mass, strength, bone density, mental focus, mood, fat loss, and other important factors in both men and women.

Common complaints for men with hypogonadism include: lower sexual desire (libido), erectile dysfunction (softer erections or lack of erections), depression, low energy and appetite, changes in body composition (lower lean body mass and higher abdominal fat), lower strength, reductions in body and facial hair, less mental focus and  decreased height and osteoporosis (decrease in bone density).

Normalizing testosterone in people who have lower than normal levels have dramatic benefits, among which are increased sexual desire, lean body mass, bone density, strength, mood, motivation, mental focus, and stamina. However, these benefits can be erased if proper monitoring, dose adjustment, and appropriate choice of testosterone replacement option are not accomplished.

Determining If You Have Low Testosterone

In addition to blood tests and physical examination, a brief screening instrument has also been developed by researchers at St. Louis University to aid in the diagnosis of hypogonadism. Known as the Androgen Deficiency in the Aging Male (ADAM) questionnaire:

  1. Do you have a decrease in sex drive?
  2. Do you lack energy?
  3. Have you experienced a decrease in strength and/or endurance?
  4. Do you feel shorter? Have you lost height? (Lower bone density can decrease height.)
  5. Have you noticed a decreased enjoyment of life?
  6. Are you sad and/or grumpy?
  7. Are your erections less strong or gone?
  8. Has it been more difficult to maintain your erection ?
  9. Are you falling asleep after dinner?
  10. Has your work performance deteriorated recently?

Other questions that are usually not asked by doctors, but which I have found to be important are the following:

  • Are you relating well with people around you?
  • Are you being loving to your lover or life partner?
  • Are you able to pay attention when someone talks to you?

Low testosterone can cause problems that go far beyond sex and the body. It affected the way that people related to others and the ability to handle stress at work and in life.

Note that several of the above-mentioned problems can be caused by many other issues unrelated to low testosterone. Depression, anxiety, stress, medications and/or sleep disorders can cause nine of those 10 symptoms (decrease in height would be the only item unrelated to anything but bone loss or back surgery). This questionnaire is not a perfect predictor of low testosterone and should not replace tests for testosterone blood levels.

The benefit of this questionnaire is that it may encourage some men to seek medical advice.  Then they can get their testosterone checked and have a physical examination to help determine whether they are indeed hypogonadal.

Causes of Low Testosterone

As discussed before, hypogonadism is caused when the testicles fail to produce normal levels of testosterone. In one type of hypogonadism, testosterone levels are low, while LH and FSH are elevated. In another, there is not enough secretion of LH and FSH needed to tell the testicles to produce needed testosterone.

Some commonly used medications such as Megace (an appetite stimulant), Nizoral (an anti-fungal agent), Prednisone (an anti-inflammatory corticosteroid) and Tagamet (an antacid) can also lower testosterone production. Illness and aging can cause a decrease in testosterone and/ or an increase in sex hormone binding globulin (SHBG). Furthermore, high prolactin hormone levels may suggest a pituitary tumor that may be causing a decrease in testosterone production.

It is important that your doctor measure hormones in the HPGA cascade to diagnose what kind of hypogonadism you have. The most common kind of hypogonadism presents low testosterone with normal or elevated FSH and LH levels, which indicates that your testicles are not responding to the signals of both LH and FSH. This is what is called primary hypogonadism.

Diagnosis of Testosterone Deficiency

Lab work will play an important role in diagnosing hypogonadism. Your doctor will likely check your total testosterone and your free testosterone levels. There are some things you should know about these tests, including what they represent and when they should be done.

A “normal” total testosterone scale from most laboratories is generally between 300 and 1,000 ng/dL for men and between 25 and 90 ng/dL for women.  The normal range from most laboratories for free testosterone usually is between 3.06 and 24 ng/dL for men and between 0.09 and 1.28 ng/dL for women. There is not a total agreement among lab companies and medical guidelines about what the “normal” testosterone range is for men and women.

As mentioned earlier, free testosterone is not bound to blood carrier proteins, so it is “free” to diffuse readily into cells where it signals them to adjust their activity. Some studies report that free testosterone may be a better indicator for quality of life and lean body mass, but there are some conflicting studies on this issue.

Since aging and illness can increase SHBG, which can attach to testosterone to impair its effectiveness, it becomes more important to test for free testosterone if you are older or being challenged by illness.

Measures of free testosterone are controversial. The only standardized and validated method is equilibrium dialysis or by calculating free testosterone levels based on separate measurements of testosterone and SHBG. Other measures of free testosterone are less accurate.

Here are the testosterone tests you can buy at DiscountedLabs.com without a doctor’s order and in most cities in the United States:


  Testosterone + LH + FSH Panel

This panel includes: Total and Free Testosterone (LC/MS), Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH) at substantial savings that buying each test separately.


  Testosterone, Free, Bioavailable and Total (Upper Limit T 1,500 ng/dL) plus SHBG

This testosterone test panel includes: 1- Total testosterone, 2- Calculated free testosterone, 3- Bioavailable (unbound) testosterone, 4- Sex hormone binding globulin (SHBG), and albumin. Testosterone upper limit under 1,500 ng/dL (ECLIA, immunoassay)


  Testosterone, Free, Bioavailable, and Total, LC/MS (No Upper Limit) plus SHBG

This Testosterone Panel Includes 5 Tests: Total Testosterone (LC/MS most accurate assay), Free Testosterone, Bioavailable Testosterone (Free T plus albumin-bound T), Sex Hormone Binding Globulin (SHBG), and Albumin.


  Testosterone, Hematocrit, Ultra Sensitive Estradiol and Prolactin Panel

This discounted lab test panel for men includes total testosterone by liquid chromatography/mass spectrometry (the most accurate testosterone test), free testosterone, hematocrit, ultrasensitive estradiol and prolactin hormone. 


  Testosterone, Thyroid and Estradiol Panel

Ordering these 5 hormone tests as a panel saves you over $20 when comparing it to buying tests separately.


  Testosterone, Total, LC/MS (No Upper Limit)

This test includes total testosterone performed by liquid chromatography/mass spectrometry, the most accurate testosterone test and one without an upper limit. It does not include free testosterone.   


  Testosterone, Total, LC/MS and Free (Equilibrium Ultrafiltration)

This panel includes total testosterone measured by the most accurate method (liquid chromatography/mass spectrometry), free testosterone percent by equilibrium ultrafiltration, and free testosterone calculated from percent free T.


Items 1-12 of 28

per page
Set Descending Direction

Items 1-12 of 28

per page
Set Descending Direction