Testosterone

 Testosterone in men & women

Testosterone increases muscle mass and muscle strength as well as bone density and bone maturity in both sexes and influences fat and sugar metabolism. 

Testosterone is the main male sex hormone (androgen). It occurs in both sexes, but in women in a significantly lower concentration. In the male body, testosterone is mainly produced in the testicles, in small quantities also in the adrenal glands. In women, the hormone comes from the ovaries and adrenal cortex. In the blood, testosterone is largely bound to proteins ( albumin, sex hormone-binding globulin / SHBG) and thus transported to the various organs, where it works.

What is the function of testosterone?

In the male embryo, the penis, scrotum, and prostate develop under the influence of androgens. In puberty, testosterone leads to the growth of the sexual organs, the maturation of sperm and the development of a male appearance:

Shoulders and chest become wider

the larynx grows (Adam’s apple)

the voice gets deeper (broken voice)

hair increases (beard, armpit and pubic hair)

the facial features become coarser (protruding chin, broad jaw).

In addition, testosterone increases sexual desire (libido), the drive, but also aggressive behavior.

The function of testosterone in men and women

The hormone increases muscle mass and strength as well as bone density and bone maturity in both sexes and influences fat and sugar metabolism.

Testosterone in women

In women, high testosterone levels can lead to the following changes:

an increase in body and facial hair (hirsutism)

acne

Deepening of the voice

Clitoral growth

How testosterone affects women in particular on bones, muscles, breast tissue and endometrium as well as on sugar and fat metabolism, physical appearance, sexual function, and mood have not yet been completely clarified. Further research is needed to improve understanding.

When can testosterone levels change?

The testosterone level can be too high if the hormone is produced excessively by tumors, such as the testes, ovaries or adrenal cortex – or if it is supplied as an external doping agent.

Furthermore, rare congenital diseases lead to an increase in testosterone (adrenogenital syndrome, complete androgen resistance). In women, androgen levels may also be elevated as part of polycystic ovarian syndrome.

Testosterone levels can be too low for severe general illnesses, alcoholism, heavy weight loss (e.g. anorexia nervosa ) or stress. In addition, the concentration of the hormone can be too low if the testicles are damaged (e.g. due to injuries, inflammation or tumors), if you take certain medications ( pill, glucocorticoids) or if you have specific diseases ( Addison’s disease, Klinefelter syndrome).

When is testosterone levels too low in men?

The production of androgens decreases steadily in men in old age. Previously, this process was called – based on the menopause or the menopause in women – as andropause or climacteric virile.

However, these terms are not very accurate. Because while there is a massive drop in female sex hormones in women within a short period of time, testosterone in men only gradually decreases. The following table shows average age testosterone levels in men:

Age-corrected testosterone levels

Age (years) Testosterone (ng / ml)

20-29 3.1 – 8.3

30-39 3.0 – 8.3

40-49 2.8 – 7.0

50-59 2.4 – 6.3

60-69 2.1 – 5.4

70-89 1.7 – 4.9

The level slowly begins to decrease in the fourth decade of life, by about one to two percent annually. Only some of the older men have testosterone levels that are significantly lower than those of young, healthy men. If there is a testosterone deficiency in men in old age that causes complaints, this is nowadays referred to as testosterone deficiency syndrome (TMS) or partial androgen deficit of the aging man (PADAM).

The two largest groups of men with low androgen levels are chronically ill and very old men. It is not yet known what long-term health effects a symptom-free hormone deficiency has for these people and whether they benefit from testosterone even without symptoms.

When is testosterone levels too low in women?

It is not yet clear which testosterone levels in women are considered “normal” in the course of life. One thing is certain: The production of testosterone also decreases in women with increasing age. However, unlike estrogens and progestogens, there is no massive drop in testosterone during menopause. In addition to age, the cycle and time of day also affect women’s androgen levels.

How exactly low androgen levels affect women is not known. Therefore, the US Endocrine Society recommends not diagnosing “androgen deficiency” in women. She also advises against testosterone administration, although there are indications that women can benefit from androgen intake in individual cases.

Because: According to the society, there has not yet been sufficient research on whether low testosterone levels harm female health in the long term and whether long-term use of androgens is harmless for women.

How does a testosterone deficiency manifest itself?

The symptoms of a testosterone deficiency depend on the age at which it occurs. Possible characteristics are:

Decreased sperm count

Shrinking testicles

osteoporosis

Depressive mood

A testosterone deficiency is only treated if it also causes symptoms. Treatment can be given by injection, tablets or even plasters.

++ More about: Testosterone deficiency ++

When and how is testosterone measured?

The testosterone level fluctuates in the male sex during the day. Over the course of 24 hours, it also drops below normal values ​​in up to 15 percent of young, healthy men.

Measurements should therefore always be taken during the morning high, i.e. between 8 a.m. and 10 a.m. With borderline mirrors, it is advisable to repeat the measurement after two to four weeks. Because up to a third of the patients then have a value in the normal range.

Since a large part of the testosterone in the blood is bound to transport proteins such as SHBG, their concentration influences the measured testosterone level. For example, overweight, diseases of the thyroid gland ( hypothyroidism ), liver (cirrhosis) or kidneys (nephrotic syndrome) and taking certain medications (antiepileptics, estrogens) can lead to changes in SHBG levels.

In this case, special measurements are required that determine the “free” testosterone not bound to proteins. The total testosterone level (free plus protein-bound testosterone) in the blood is normally determined. There are also other special measurements that determine the so-called bioactive testosterone.

This means the testosterone that is not “firmly” bound to SHBG – ie the free plus the “loosely” testosterone bound to albumin. It was previously believed that the concentration of bioactive testosterone corresponded to the actual effect of the hormone on the human body. Nowadays it is known that the connection between testosterone levels and hormonal effects is more complex.

Should testosterone be determined from a certain age?

There is currently no recommendation to generally check androgen levels in men from a certain age. According to experts from the Endocrine Society, this would be much more likely to call men sick and treat them appropriately because of a “deficiency” that causes no symptoms.

However, there are a number of conditions and situations that are most likely associated with a testosterone deficit and in which it is therefore useful to determine the level of hormones. These include:

long-term use of certain medications (glucocorticoids, opioids)

infertility

Pituitary disorders

kidney disease requiring dialysis

COPD

Diabetes mellitus type 2

osteoporosis