Testosterone is the primary sex hormone in males that is produced from the male testes. This is also produced from the ovaries in females and the adrenal glands in both sexes, although in smaller quantities. Being an androgen, testosterone is responsible for the development of male characteristics, initiating the development of male reproductive organs while we are fetuses, and it plays an important role in sperm production.
Testosterone is responsible for the development of certain male features during puberty such as deepening of the voice, increase in height, body and pubic hair growth, bone and muscle growth, and changes in sexual behavior.
How and where testosterone is made
Like other steroid hormones, testosterone is synthesized from cholesterol. However, an increase in the level of blood cholesterol does not signify an increase in your levels, as they are are centrally regulated by the hypothalamus-pituitary-gonad axis. The hypothalamus releases gonadotrophin-releasing hormone (GRH) which stimulates the pituitary gland to produce luteinizing hormone (LH), thereby stimulating the release of testosterone from the gonads.
As the level of testosterone increases, through a negative feedback mechanism, this sends signals to the hypothalamus and the production of GRH is suppressed. Consequently, the LH is released by the pituitary gland. When this happens, the level begins to decrease and the negative feedback to the hypothalamus decreases, so it continues to secrete GRH and the cycle continues.
Testosterone levels in the body
Levels peak by early adulthood and gradually decreases as men age to roughly 1% to 2% annually, beginning in the 40s. Moreover, more than 1/3 of men aged 45 and above have reduced levels of testosterone than what is considered normal. A normal healthy male produces 5 mg or 1.8×10-4 ounces of testosterone daily.
In reality, normal levels are difficult to determine as the levels vary throughout the day and are affected by body mass index (BMI), diet, alcohol consumption, age, certain medications, and illnesses. This is supplemented by Harvard Health, which says that the levels may vary greatly over time and even throughout the day, thus determining optimal levels of testosterone somewhat controversial.
In the absence of symptoms, a low level taken once may be insignificant especially if the levels taken at other times were normal. The American Urology Association (AUA) identifies low blood testosterone (Low-T) as less than 300 nanograms per deciliter (ng/dL).
How to tell if you have low T
By the age of 50 and above, some men may experience signs and symptoms of testosterone deficiency which would include loss of body hair, decrease in libido or impotence, reduced sperm count, erectile dysfunction, reduced muscle mass, brittle bones, weight gain, small testicles, enlarged breasts, hot flashes, irritability, poor concentration, and depression.
Although declining levels may be normal as one ages, several risk factors could accelerate the process including infection, injury, chemo or radiation therapy, stress, alcoholism, obesity, chronic illness, and some medications especially corticosteroids and those used for the treatment of prostate cancer.
Causes of low T
Low T levels are determined through multiple blood tests in conjunction with physical examination and review of signs and symptoms. In cases where low levels have been found, other tests are to be performed before therapy to confirm the cause and determine the appropriate treatment. There are some cases where there is a specific identifiable cause for the low levels of testosterone whilst there are somewhere no specific cause is identified. In the latter, testosterone therapy would usually be effective management.
Certain medical conditions may cause significantly low testosterone levels in men including autoimmune diseases, chronic hepatic or renal disease, chronic obstructive lung disease, genetics, cardiovascular disease specifically, heart failure, HIV/AIDS, infection such as mumps, metabolic disorders, obesity, tumor (prolactinoma) located in the pituitary gland, testicular cancer, Type II Diabetes, injury to the testicles.
Potential causes may include infection of the testes (orchitis), dysfunction or tumors of the pituitary gland, pubertal delay, trauma to the head, congenital defect, estrogen excess, severe primary hypothyroidism, acute or chronic illnesses, medications such as opioids and corticosteroids, and congenital disorders such as Klinefelter Syndrome and Kallman Syndrome.
A variety of conditions may cause or may be linked to having low testosterone levels, and depending on the specific cause, the treatment varies. In cases where the cause is excessive secretion of hormones by the pituitary, for example, medications or surgery may be indicated to manage the condition.
Treatment for low T
When no specific cause has been identified, the most common treatment option is testosterone replacement therapy or testosterone therapy. Both the FDA (Food and Drug Administration) and AUA (American Urological Association) suggest that testosterone therapy (TT) be used to treat congenital disorders such as Klinefelter. This may be indicated for cases where there is injury or infection of the testicles or if the testicles were removed due to cancer.
Currently, testosterone therapy is the generally accepted treatment option primarily for delayed puberty in males and low testosterone secretion whether due to dysfunction or failure of the pituitary gland, hypothalamus, or testes.
Testosterone replacement therapy works by increasing levels in the body via regular administration of testosterone, and this may take in a variety of forms such as patches, gels, pellets, or it may be given intramuscularly through injection.
Still, like any other form of treatment, the patient must be informed of the risks of supplementation, one of them being the reduction in the amount of natural testosterone being produced by the body. This can also cause elevated red blood cell levels which is reflected by the patient’s hematocrit, and so careful monitoring of hematocrit levels through a blood test is essential.
Your levels are more important than you think it is, and it is not just because it has to do with reproduction. This is why there is the need to maintain the appropriate levels in the body to develop and function normally and avoid having low T. Should your testosterone levels be low, this should not cause too much worry, as there are options to treat it and get your numbers back up.