Follicle Stimulating Harmone (FSH)

The chemical messenger inside the body is secreted by the endocrine glands directly into the blood that acts on different aspects of bodily functions and processes known as hormones. Follicle-stimulating hormone (FSH) is a glycoprotein polypeptide or simply a gonadotropin hormone. Its effects and activities are chiefly associated with the human reproductive system.

Production Site:

Gonadotropin cells of the anterior pituitary glands synthesize and secrete the follicle-stimulating hormone (FSH) in the bloodstream. The control of FSH secretion from the pituitary gland is unknown. It is reported that the gonadotropin-releasing hormone (GnRH) plays an important role in the secretion of FSH. But GnRH is not directly correlated with an increase in circulating FSH. The cessation of FSH is associated with hypothalamic-pituitary disconnection. Hypothalamic-pituitary gonadal axis subjects FSH to the estrogen feedback from the gonads.



It regulates the reproductive processes of the body concerning growth, development, and pubertal maturation. The maturation of primordial germ cells in both males and females is stimulated by the follicle-stimulating hormone.

Roles In Males

In Males the Sertoli cells are induced by the FSH to secrete androgen-binding proteins (ABPs). Inhibin’s negative feedback mechanism on the anterior pituitary gland regulates its activity. The activation of Sertoli cells sustains spermatogenesis and the secretion of inhibin B is also stimulated.

Consequences In Males

In Males The primary spermatocytes are stimulated by the FSH to undergo the first division of meiosis to form secondary spermatocytes. The production of androgen-binding proteins by the Sertoli cells of the testes is enhanced by FSH which initiates spermatogenesis.

Roles In Females

In Females the FSH initiates the follicular growth by affecting the granulosa cells. The rise in inhibin B cause a decline in the FSH level in the late follicular phase. There is a slight rise in the FSH level at the end of the luteal phase that has its significance in starting the next ovulatory cycle.

Consequences In Females

In Females The follicle-stimulating hormone controls the menstrual cycles. The growth and recruitment of the immature follicles in the ovary are stimulated by the FSH.

What are normal FSH levels by age?

The follicle-stimulating hormone normal levels fluctuates according to pubertal age.


In Males

• Before puberty - 0 - 5.0 mIU/mL (0 - 5.0 IU/L)
• During puberty - 0.3 - 10.0 mIU/mL (0.3 - 10.0 IU/L)
• Adult - 1.5 - 12.4 mIU/mL (1.5 - 12.4 IU/L)


In Females

• Before puberty - 0 - 4.0 mIU/mL (0 - 4.0 IU/L)
• During puberty - 0.3 - 10.0 mIU/mL (0.3 - 10.0 IU/L)
• Women who are still menstruating - 4.7 - 21.5 mIU/mL (4.5 - 21.5 IU/L)
• After menopause - 25.8 - 134.8 mIU/mL (25.8 - 134.8 IU/L)

FSH Related Abnormalities

During childhood, the FSH levels are normally low. During the reproductive years, fluctuations in FSH levels lead to certain abnormalities.

High FSH Levels:

In females, the FSH level is high after menopause. It may contribute to cardiovascular diseases or postmenopausal osteoporosis. If the FSH level is high during the reproductive years, it is abnormal and is associated with a number of complications including premature ovarian aging/failure, gonadal dysgenesis, turner/ Klinefelter/swyer syndrome, castration, testicular failure, etc.

Low FSH Levels:

Low levels of FSH are chiefly associated with hypogonadism or simply the failure of gonadal function. In males, failure in the production of a normal number of sperms, and in females, interrupted reproductive cycles is reported. The consequences of low FSH secretions may include polycystic ovarian syndrome + infertility, hypothalamic suppression, hypopituitarism, hyperprolactinemia, gonadotropin deficiency, etc.

FSH Blood Test

FSH Blood test is performed to check the amount of follicle-stimulating hormone present in your blood or urine.


There may be different reasons for conducting the FSH test of a woman, man, or sometimes children as well.

FSH Test For Women

In women, the FSH test is associated with the assessment of infertility problems or interrupted menstrual cycles. It may also be done for diagnosing the diseases involving the ovaries or the disorders of the pituitary gland.

FSH Test For Men

FSH tests in men may be conducted to analyze low sperm count. Another reason for conducting the test may be the assessment of the gonadal failure of testicular dysfunction.

FSH Test For Children

FSH test in children is associated with the diagnosis of the onset of puberty on both cases either if the child experiences early or delayed puberty, FSH test is conducted for the assessments.



Before the test, you must address in front of your doctor any existing medical disorders like ovarian cyst, vaginal bleeding, sex-dependent hormone tumors, or thyroid disease, etc. Also talk to your doctor about any prescription or non-prescription medications, dietary supplements, and also any type of birth control if you use, such as a pill or an intrauterine device, etc. because it may play a role in the test.



The procedure of the FSH blood test is quite simple as it only involves taking a sample of blood from the patient’s body. The blood is mostly taken from the arm. Before inserting the needle, the site is cleaned and sterilized by an antiseptic, and then the needle is injected to draw the required amount of blood. After removing the needle pressure is applied with a cotton ball on the site of injection for few minutes then a bandage is placed over it. The blood sample is forwarded to the lab for the assessments.


The results of the test may vary concerning the gender and age of the patient. In women, the results may also vary if she is in her monthly cycle.

High FSH Levels

In Women

If a woman if we try to find out what causes high FSH levels, then the possible medical diseases include polycystic ovarian syndrome, chromosomal abnormality, loss of ovarian function or ovarian failure, or menopause. High FSH levels and pregnancy can also occur but, the entire pregnancy has to be dealt with extreme caution to avoid any chances to miscarriage. FSH test is also conducted to determine a woman’s ovarian reserve (women’s age-related fertility potential). If she reports a high level of FSH then this indicates that the chances of becoming pregnant may be lower than expected for her age and such cases probably need infertility treatments.

In Men

In order to understand what causes high FSH levels in males, the possible causes include Klinefelter’s syndrome or any testicle-related disorders, either they are absent, not functioning properly, or are damaged.

In Children

High FSH level in children indicates that the onset of puberty is near. How to Reduce High FSH Levels Generally, it is easier to reduce high levels of FSH by using various medications such as Lupron and estrogen, however medications should only be taken after checking FSH levels twice.

Low FSH Levels

In Women

Its chief indication in women is the slow or total absence of the production of eggs. Other indications may be the dysfunction of the hypothalamus or pituitary gland or any tumor which may be interfering with the brain’s activity of producing FSH.

In Men

Low FSH levels report that the man is not producing sperm. Other indications are the same as for women like interference of any tumor with the brain activity or the dysfunction of the pituitary gland or hypothalamus.

In Children

Low FSH levels are the clear indication of delayed puberty in children, this means that the sexual features and organs are not developing at the time when they should.



Follicle-stimulating hormone is of great importance for the proper working of the reproductive system in both men and women and in children too. Any fluctuation in the FSH level may be associated with any of the above-mentioned disorders. At Australian concept fertility center, we aim to treat both high FSH infertility and low FSH infertility, with the help of our fertility experts we finds the root cause of FSH fluctuations through various clinical and laboratory investigations and treat the condition accordingly to ensure fertility is not affected due to abnormal increase or decrease of Follicle Stimulating hormone. Apart from natural abnormality, the FSH level in the body is also affected by stress or the severely underweight condition of a person. In case if any couple is facing the issue of delayed pregnancy, they should consult with a doctor who might check the FSH levels for further diagnostic and treatment procedures.