Testosterone, estrogen and progesterone are without a doubt the best known sexuality-related hormones. Although traditionally the latter two have been associated with women and the former with men, the truth is that these are three hormones that both men and women have in their bodies (although at different levels). Of these three, the ones most remembered by the majority of the population are testosterone and oestrogen , with progesterone often relegated to a secondary role . However, we are dealing with a hormone of great relevance to the body, whose importance and roles we will talk about throughout this article.

Progesterone: general characteristics

One of the main sex hormones secreted by the body is known as progesterone. Progesterone is a steroid of great relevance, being in fact considered as a precursor substance of both testosterone and estrogens.

It is mainly linked to female sexuality, being secreted mainly in the ovaries (being the corpus luteum of these what emits it) and the placenta. This secretion presents great increases in the later moments of the ovulation, being linked to the thickening of the endometrium. However, ovaries and placenta are not the only points where progesterone can be found, and it is also synthesized in small quantities by the adrenal glands.

This hormone is especially known for its role in reproduction , and especially at the time of pregnancy and gestation, although it is associated with a large number of roles and functions in our body. Its production at the ovarian level begins with the first menstruation and varies throughout the life cycle. Great variations can be observed after ovulation, during pregnancy and menopause, as well as in different medical conditions such as adrenal hyperplasia.

Also present in males

Although we generally identify progesterone with the female gender, the truth is that, as with testosterone and estrogen, it is a hormone that is present in both sexes. Despite the fact that its main point of synthesis is the ovaries, as we have said it is also secreted in the adrenal glands .

In addition, in the case of men it is also synthesized in a very small amount by the seminal vesicles. Thus, although it predominates in women, men also have a certain amount (although much less than women) of progesterone in their bodies.

Some of the main functions of this hormone

As we have previously stated, progesterone is a very important hormone for the human body. Although some of the most recognized hormones occur in the female gender, they also alter and are linked to different roles and functions in men. Among the many roles this hormone plays, some of the most prominent are the following.

1. Prepares the endometrium for embryo implantation

One of the best known roles of progesterone has to do with reproductive function. Progesterone actively participates in the preparation of the endometrium , producing its thickening in order to facilitate a possible implantation of a fertilized egg.

2. Contributes to the maintenance of pregnancy

In the same area as the previous point, the action of progesterone allows the pregnancy to be maintained over time by not allowing the existence of changes in the endometrium that could generate the detachment of the embryo, such as those typical of the menstrual cycle. It paralyses and slows down the action of oestrogens and other hormones .

3. Regulates the menstrual cycle

The presence of low levels of progesterone has been associated with irregular and abnormal menstruation, and exogenous progesterone is often prescribed to improve cycle regularity .

4. Linked to libido

Although we tend to think more about other hormones when we talk about sexual desire, progesterone has been shown in various studies to have a relationship with the level and experience of sexual desire and sensuality.

5. Action on the brain

Progesterone not only has effects at the sexual and reproductive level, but also generates effects at the level of the nervous system. Specifically, it has been observed that generates a depressive effect, decreasing nerve activation and generating a relaxation of the nervous system. In fact, it facilitates physical relaxation and sleep, having sedative effects. Different studies seem to reflect that it also has antidepressant and anxiolytic action.

In addition, it has been found to have neuroprotective effects in the brain that make neuronal degeneration difficult, as well as contributing to the regulation of apoptosis or programmed cell death.

6. Growth and maturation

Progesterone is also a relevant hormone in terms of sexual maturation and physical development. For example, is linked to the onset of puberty and the development of secondary sexual characteristics (the latter especially in females).

7. A role in the skeleton

The formation, strength and maintenance of bone density are also affected by progesterone. Specifically, this hormone has been associated with greater functionality of osteoblasts , which facilitates the generation and formation of bone

8. Breastfeeding

Progesterone helps the development and growth of the breasts and mammary glands in women, and helps prepare them for breastfeeding during pregnancy. However, the release of milk itself is linked to prolactin.

9. Contributes to glycemic regulation

Another of the multiple roles and functions of progesterone is its participation in regulating glucose levels , in both women and men.

10. Action on the endocrine system

The role of progesterone also extends to the endocrine system, and it is considered a precursor to both estrogen and testosterone. It also participates in the regulation of the synthesis and release of adrenal hormones.

11. Contributes to avoiding neoplasms

Progesterone also plays an important role in the male organism, contributing among other things to preventing hyperplasia of the prostate and the emergence and spread of cancer at this point in the body. This is due among other factors to the fact that progesterone prevents testosterone from turning into dihydrotestosterone.

12. Produces temperature increase

The presence of progesterone has been associated with an increase in temperature at different points in the body, something associated with the maintenance of vital organs. Specifically, this increase appears in the torso and abdomen, increasing blood flow to these areas.

13. Linked to the immune system

Progesterone is also considered to act on the immune system, facilitating the protection of the body. It also helps to ensure that the pregnancy is not considered a harmful agent and that there is no reaction of the immune system against the foetus by producing immunosuppression of some components of the immune system while allowing some types of leukocytes to interact with the endothelium to facilitate the implantation of the embryo . It has also been seen to improve the body’s immunity, as occurs for example at the level of the intestinal mucosa.

14. Regulates body fat

Progesterone is diuretic and has also been associated with lipid control and management . Among other effects, it participates in the transformation of lipids into energy, as well as in the management of fat accumulation in different parts of the body.

Disorders and alterations to which it is linked

This hormone is of great importance for the organism, and its lack or excess can generate different repercussions or can mitigate the effect of different alterations.

For example, progesterone has been found to inhibit the effect of estrogens , which has sometimes been used in the treatment of problems such as endometriosis. The lack of progesterone is also associated with more liquid, abundant and irregular menstruation. Progesterone-containing drugs are often prescribed to reduce the symptoms of polycystic ovaries.

It also prevents hypothyroidism caused by high levels of estrogen. Similarly, its presence in adequate levels is observed to make the presence of miscarriages more difficult . In men, it protects against prostate cancer.

On the other hand, an excess of this hormone has been associated with the presence of drowsiness, nausea, cramps and headaches. It can also cause breast hypersensitivity, decreased libido, mood swings (linked to premenstrual dysphoric syndrome), and fluid and fat retention.

Bibliographic references

  • Finkelstein, J.S. et al. (2013). Gonadal steroids and Body Composition, Strength and Sexual Function in Men, The New England Journal of Medicine 369; 1011-1022.
  • Gibson, C.L.; Gray, L.J.; Bath, P.M. & Murphy, S.P. (2008). Progesterone for the treatment of experimental brain injury; a systematic review. Brain 131 (Pt 2): 318-28