How does finasteride work?

The testosterone is considered the primary male hormone. It occurs mainly in the testes, but also in small amounts in the ovaries in women, and in both sexes in the adrenal (or adrenal) glands.

Testosterone has many functions in the body. Promotes the development of the male reproductive system of the fetus inside the uterus, changes that males go through during puberty, stimulates muscle growth, preserves bone density, interferes with energy levels and physical activity, sexual desire, aggression and in many other aspects.

In some parts of the body such as the prostate (which participates in the production of sperm and ejaculation, and may be associated with sexual pleasure in men) and the hair follicles (structures in which the tufts of hair are produced), About 5% body testosterone is converted to dihydrotestosterone, a kind of strong version of the hormone (DHT can be 2 to 5 times stronger than testosterone).

DHT is essential for the formation of the male fetus (more important than testosterone itself), participates in the maturation of the sexual system of men during adolescence and regulates the functioning of the prostate, but does not seem to have much influence on growth muscle, bone density and other systems in which testosterone does interfere.

The problem is that DHT can also cause hair loss.

The hormone connects to the androgen receptors present in the hair follicles and causes the hair growth phase to be shorter, gradually reducing the size and activity of the follicles, and can even cause it to stop by full.


What topical finasteride does is inhibit the action of the enzyme 5α-reductase, which converts testosterone to DHT. Therefore, DHT levels in the body are reduced, but there is no significant impact on the level of testosterone in the body.

Results of finasteride

Finasteride is able to reduce the progression of hair loss (make baldness slower or slower than normal) and allow some of the follicles in miniaturization process to recover, which can increase the number of hairs Apparent and help improve bald areas.

But you have to be realistic about the possible outcomes before starting the treatment with finasteride. Although the drug is effective in most cases, the patient probably will not recover all the hair that has lost in life (several follicles may have been permanently disabled). In addition, since the hair only grows an average of 1.25 cm per month, the treatment can take a few months to have visible effects (the maximum gain is normally reached after two years of use of finasteride).

Finasteride works best in mild or moderate cases of baldness, where hair loss only reaches the top of the head (recovery in cases of complete baldness is unlikely). The results are not considered permanent: if the treatment is interrupted, the hair loss can appear again and affect the hairs that have already grown.