Both males and females secrete testosterone, but it is a primary reproductive hormone in males. Females only need this hormone in a minimal amount for functions like improved bone health and increased sexual desire. In males, testosterone drives different male functions and characteristics. Learn more about testosterone in this article.
There are many chemicals that are secreted by the glands and certain parts of the brain that control various functions in the human body. They are called hormones. In men, male sex hormones, called androgens, modulate the development and maintenance of male characteristics. The most important of these androgens is testosterone.
Testosterone is a hormone that is mostly produced in the testicles of males and the ovaries of females. In females, it is produced in relatively smaller amounts. The adrenal glands also produce a hormone called dehydroepiandrosterone, which is later transformed into testosterone.
Testosterone is the main androgen, as it stimulates the development of male characteristics. Natural testosterone produced in the body is also anabolic, meaning it promotes muscle building.
From when life begins through adulthood, testosterone subserves various functions. Below is a summary of the functions of testosterone during the development of a baby in the womb, the puberty stage, and adulthood.
As early as seven weeks of pregnancy, the testicles begin to develop rapidly in the fetus. Once formed, they start to produce testosterone. The testosterone produced then activates the development of the rest of the male reproductive system. Internally, the male reproductive system includes the prostate gland, vas deferens, and urethra, and externally, it includes the penis and scrotum.
As males approach puberty, there is a surge in testosterone production. This causes facial and pubic hair to grow, as well as increased muscle and bone mass. It also causes the voice to deepen and the reproductive organs to begin to mature.
Testosterone is responsible for sperm production and increased sexual drive, called libido. It also helps the body synthesize new red blood cells for optimal tissue functioning.
Testosterone also increases sexual drive in female adults. It is also involved in other functions, such as increasing muscle mass and bone density. However, most of the testosterone produced in them is converted into the female sex hormone, estradiol.
Although information exists about normal testosterone levels across various age groups, most are not foolproof. A 2022 study on 1,486 men revealed normal ranges of testosterone measured in nanograms per deciliter (ng/dL) as follows:
Therefore, cutoffs for low testosterone levels were set at 409, 413, 359, 352, and 350 ng/dL, respectively.
In order to assess testosterone levels, doctors request tests like:
It is rare to find a male adult with too high testosterone levels. However, high testosterone levels in children can cause them to attain puberty too early. Puberty earlier than 8 years in girls and 9 years in boys is described as precocious.
In adult females, high testosterone levels is one of the diagnostic criteria for polycystic ovarian syndrome (PCOS). PCOS is a female medical condition characterized by ovarian cysts, irregular menstruation, as well as excess body and facial hair (hirsutism).
The most important effect of low testosterone in women is a loss of sexual desire. In males, on the other hand, low testosterone is diagnosed as a medical condition called hypogonadism. Hypogonadism is a medical condition that occurs when the sex glands (also called gonads), which are the testes in males and the ovaries in females, produce little to no sex hormones.
Hypogonadism is of two types: primary and secondary hypogonadism.
The problems that low testosterone causes vary with age and are explained below.
Low testosterone during the development of a fetus in the womb hinders the normal development of male characteristics. This results in a baby that is genetically male but does not have male genitals. Instead, they have the female external genitalia.
Slow growth of the pubic hair, penis, and testicles are the hallmarks of low testosterone during puberty. Low testosterone during puberty can also cause a slow increase in height, less voice deepening, and reduced bone and muscle mass.
The level of testosterone in male adults declines with increasing age. Nevertheless, if this happens at a faster-than-normal rate, it can cause significant problems. The most worrisome of them is erectile dysfunction, popularly known as impotence. People with erectile dysfunction are unable to get and sustain an erection long enough for penetrative sexual intercourse.
Low testosterone levels in adult males can also cause:
Low testosterone can be treated using testosterone replacement therapy (TRT). A doctor might recommend it when the testosterone level is abnormally low and the patient has significant symptoms.
However, older people with age-related low testosterone levels are often not eligible for TRT.
Testosterone replacement therapy is effective in increasing testosterone levels and comes in various forms, including:
These testosterone replacement therapy methods are typically preferred because they deliver testosterone directly into the blood without going through the liver. However, it is worthy of note that testosterone pills are also available. But, there is evidence to show that some of them damage the liver.
The only currently approved oral pill for testosterone replacement is undecanoate (Jatenzo)⸺with a recommended starting dose of 237 mg twice per day)⸺which the FDA approved in 2019 for treating low testosterone levels due to specific medical conditions like damage to the pituitary gland.
Testosterone is a very important hormone in the human body, particularly in males. Therefore, the necessity of knowledge of its functions among the male population cannot be overemphasized. This article is intended to add to that body of knowledge and help you understand the role of this hormone and what can happen when there is an imbalance of this hormone.
If you have been diagnosed with high or low testosterone levels, your healthcare team will suggest a treatment method that is specific to your condition.
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