Testosterone is often considered the sex hormone, but it actually has many roles in the body.
Definition: testosterone, a male hormone
It’s about a male hormone secreted in part by the adrenal glands (located above both kidneys) and sexual organs. Often considered the sex hormone, it actually has many roles in the body. “It circulates in the blood in two forms: total and bioavailable. The first is linked to the SHBG protein and has little effect on the body, while the second is free and usable by the organization”explains Dr. Pierre Nys, endocrinologist in Paris.
► In women: this hormone, synthesized partly by the adrenal glands and in small quantities by the ovaries, plays a role in sexual desire.
► In humans: Testosterone is produced as a duo by the adrenal glands and Leydig cells, located in the testicles. It is involved in the development of male physical characteristics such as the maturation of the genitals, hair growth and voice change. It plays a role in spermatogenesis (sperm maturation), libido, increasing muscle mass and bone development. She finally intervenes on mood.
Why is it prohibited among athletes?
There testosterone is included on the World Anti-Doping Agency’s list of substances and methods prohibited in competition because it is an agent anabolic. The term “anabolic” means that it increases muscle mass hence the attraction of athletes for the substance (especially among bodybuilders). Testosterone also improves physical performance, would influence energy and could boost the feeling of “power”.
Testosterone blood level
In humansa dosage may be prescribed to look for testicular or pituitary dysfunction, particularly in the presence of signs such as libido disorders and sexual problems such as erectile dysfunction.
In women, it can be prescribed when symptoms suggestive of an excess of this hormone exist: acne, oily skin and hair. But also faced with excessive hair growth in areas that are not usually hairy such as the mustache, chin or breasts… (hirsutism)
Normal testosterone level
Normal values for testosterone levels depend on sex and age.
- In humans, between 1 and 10 years of age, values are less than 0.7 nmol/l, between 10 and 20 years, they are between 1.7 and 17.5 nmol/l, between 20 and 45 years, they are between 10 and 30 nmol/l, between 7 and 28 nmol/L between 40 and 60 years , and between 60 and 75 years, these values vary between 3.5 and 17.5 nmol/l. After age 75, levels drop to between 0.4 and 9 nmol/l.
- In women, normal values for testosterone blood levels are ten times lower. Thus, between 1 and 10 years, they are less than 0.5 nmol/l, between 10 and 20 years, they are between 0.5 and 3.1 nmol/l, between 0.5 and 3.1 nmol/ l between 20 and 45 years old. Between 45 and 60 years old, the rate varies between 0.5 and 2.8 nmol/L and after 60 years, it drops between 0.3 and 1.70 nmol/l.
“Lack of testosterone is often synonymous with fatigue”
Causes of low testosterone levels
In humans, we then speak of hypogonadism. This happens in cases of testicular failure, andropause, Cushing’s syndrome, chemotherapy or irradiation as part of cancer treatment, or when taking synthetic androgens, estrogens or anti-androgens. In women, it may decrease in cases of Feminizing Testicular Syndrome (androgen insensitivity).
Causes of too high testosterone levels
In men, this can be indicative of taking synthetic testosterone and generally used by certain men, often athletes, in order to benefit from its anabolic role and increase their muscle mass. But hyperthyroidism can also be a cause. In women, it may increase in cases of hirsutism, polycystic ovaries, ovarian or adrenal tumors.
When the testosterone dosage shows a level that is too low, supplementation can be considered in men in order to compensate for the level and thus correct the symptoms that led to the dosage of this hormone. “With caution, it is sometimes desirable to increase the rate in women, their deficiency often being synonymous with fatigue”explains Dr. Nys.
On the health forum: discussions about testosterone
To remember
► Testosterone is a male hormone secreted by the adrenal glands (above the kidneys) and sexual organs.
► Testosterone circulates in two forms in the blood: total and bioavailable.
► Women also have testosterone.
► In women, normal values for blood testosterone levels are 10 times lower than in men.
► Testosterone is considered a doping product in the world of sport.
Thanks to Dr Pierre Nys, endocrinologist.