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Testosterone Replacement Therapy: Why Monitoring is Important (Part 3)

by Cecilia Lodi on July 13, 2023

influencesIn the third and final article of this series, we'll continue to list the various lab tests that should be performed on a regular basis and explain why they're crucial to managing your Testosterone replacement program safely and effectively. You should at the very least be acquainted with the following medical tests, if you are now receiving testosterone treatment or intend to in the future.


Thyroid Profile

Low total testosterone levels have been linked to hypothyroidism, which is thought to be caused by low sex hormone binding globulin (SHBG) concentrations. Low free testosterone levels, which return to normal after hypothyroidism treatment, have also been shown.

Although free testosterone levels are often normal, hyperthyroidism raises concentrations of SHBG and total testosterone. It can also enhance the aromatization of testosterone to estrogen, which may also impact sexual function and cause gynecomastia.

TSH- Thyroid-stimulating hormone (TSH) encourages your thyroid gland to generate T3 and T4 hormones. The metabolic process in your body is influenced by these thyroid hormones. TSH levels below the normal range are a sign of hyperthyroidism, while TSH levels that are extremely high are a sign of hypothyroidism. The recommended range for normal TSH 0.5- 5 µU/mL or (different guidelines show different upper TSH levels).

T4- Thyroxine, often known as T4, is one of the hormones produced by your thyroid gland. A T4 test reveals how effectively your thyroid controls the growth and energy of your body. While a T4 test is mostly used to evaluate your thyroid, it can also let your doctor know if your pituitary gland is having issues. Standard levels are between 5.0-12.0μg/dL.

T3- The most typical application of a T3 test is to identify hyperthyroidism, a condition in which the body produces an excessive thyroid hormone. T4 and TSH tests are routinely ordered alongside T3 tests. A T3 test can also be used to track the effectiveness of thyroid disease treatment. The normal range is at 80-220 ng/DL.

Free T4 and Free T3-When TSH is greater than 5, many clinicians perform tests for free T3 and free T4 (the unbound thyroid hormones) to give a more complete picture of thyroid health. Increased levels in the blood may point to an overactive thyroid, and low amounts could denote an underactive thyroid. Free T3 typically ranges from 60 to 180 ng/dL, while free T4 typically ranges from 0.7 to 1.9 ng/dL.


Iron Studies

Iron- There is a significant relation between testosterone administration and increased Iron levels. High iron levels can occur from testosterone downregulating hepcidin’s action. Hepcidin is an iron regulatory hormone induced by high iron levels, and prevents iron loading or excessive iron absorption. Another mechanism by which testosterone therapy may increase iron is through stimulating erythropoiesis or the creation of red blood cells (erythrocytes). 60-170 mcg/dL or 10.74 to 30.43 µmol/L is the normal range.

Transferrin Saturation / Iron Saturation- This test calculates the amount of iron in your blood that is bound to the protein transferrin. A high transferrin saturation frequently confirms hemochromatosis, while a low transferrin saturation typically implies iron deficit. The typical range is 20–50%.

TIBC - Total iron-binding capacity (TIBC) testing determines how well the blood can bind to iron and transport it throughout the body. If you have iron deficiency anemia, which is when there is not enough iron in your blood, your TIBC will be high but your iron level will be low. Your TIBC will be low or normal if you have an excess of iron, but your iron level will be high. Normal range is 250 to 450 mcg/dL

Ferritin- Ferritin is an iron storing protein found in the cell. Its measurement is significant in the detection of disorders of iron metabolism because serum ferritin, which is present in small amounts in the blood, typically corresponds well with total body iron stores. The standard reference range is 24 to 336 mcg/L.



A negative feedback mechanism in response to testosterone levels influences FSH and LH secretion. Low levels of testosterone and high-normal to high levels of LH and FSH are characteristics of primary hypogonadism. Low levels of testosterone and normal to low levels of LH and FSH are linked to secondary hypogonadism.

Luteinizing Hormone (LH)- In males, LH stimulates the interstitial cells of the testes (Leydig cells) to create testosterone. To differentiate between true testicular failure and secondary hypogonadism, LH testing may be advised. The range is between 1.7-8.6 mIU/ml.

Follicle-Stimulating Hormone (FSH)- Follicular hormone (FSH), which is in charge of men's sperm production, is a vital part of the body's reproductive process. It is believed that higher FSH levels in infertile males are a reliable indicator of damaged germinal epithelium. High FSH blood levels have also been associated to sperm production problems and testicular dysfunction. 1.5 to 12.4 mIU/mL is the reference value.



Dehydroepiandrosterone Sulfate (DHEA-S) - Dehydroepiandrosterone sulfate, often known as DHEAS, is a male sex hormone made by the adrenal glands, which is crucial for the production of both the male sex hormone testosterone and the female sex hormone estrogen. To determine whether your adrenal glands are functioning normally and to identify secondary causes of low testosterone in males, a DHEAS test is utilized. Blood levels are considered normal if values fall between 520 µg/dL or 3.24 to 14.04 µmol/L.


Sex Hormones

The significance of testosterone evaluation has already been addressed in the first article of this series. But by correlating Testosterone levels with other sex hormones,

Estradiol-Estradiol is the main sex hormone in females, but the male body also produces it from testosterone via the aromatase enzyme. Some men may create more estradiol due to body fat percentage, liver disease, drug effects, and genetics. Testosterone therapy may also increase estradiol levels because it may serve as a precursor.

If estradiol levels are higher than 50 and you start showing symptoms of high estradiol (gynecomastia, water retention), it may be necessary to take an estrogen blocker or an aromatase inhibitor.

Sex Hormone Binding Globulin (SHBG)- SHBG levels tend to rise as total testosterone levels rise. In contrast, when total testosterone levels are low, SHBG levels tend to fall. As men age, their SHBG levels naturally rise while their free testosterone levels fall. The relationship between SHBG levels and free testosterone is critical in determining the dose of your Testosterone treatment. Normal range is 10 to 57 nmol/L.

Progesterone- Progesterone helps to balance estrogen's effects on the male body. It is not only found in males; men also rely on this presumed "female hormone" to maintain their masculinity. Progesterone, in fact, is a precursor to testosterone, the major male sex hormone. As men age and testosterone levels begin to fall, estrogen levels rise steadily. As estrogen levels go up, progesterone levels drop. The standard value is < 1 ng/mL or 3.18 nmol/L.


Pituitary Hormones

Prolactin- Men who exhibit signs of elevated prolactin levels resulting in decreased sex drive, fertility issues, or erectile dysfunction may need the test. This is because elevated prolactin may stop the testes from producing the testosterone. Normal levels should be <less than  20 ng/mL.

Cortisol- Chronically elevated cortisol levels, according to research, can cause impotence and loss of libido in men by impeding testosterone production. Individuals suffering from unexplained testosterone deficiency should have their cortisol levels checked as a possible contributing factor. The standard range is estimated to be 5 - 25 mcg/dL.

It's imperative to regularly monitor yourself to accurately guide your hormone treatment program. Annual physicals are part of this monitoring as well for general health evaluations. It is recommended for individuals over 30 to get a yearly physical, and we urge our testosterone replacement therapy clients to do the same. Health checks for conditions including heart disease, diabetes, excessive cholesterol, and many more are part of an annual physical to aid in your general health maintenance and maximize the effectiveness of your testosterone protocol.