Male sex hormones play a major role in fertility, since they are directly associated with the sperm production process, which is called spermatogenesis. The most important hormones involved in this function are testosterone, dihydrotestosterone, LH, and FSH.
The different sections of this article have been assembled into the following table of contents.
Male fertility tests
Achieving a pregnancy is not always an easy task. If it has not happened after trying to conceive for a year, couples are strongly recommended to visit a fertility specialist to see if there is some kind of infertility issue that is preventing pregnancy.
Infertility specialists typically ask new patients to undergo a complete fertility evaluation to check fertility in both the man and the woman, since both play a part in the TTC journey, and any abnormality can be the cause of infertility totally or partially.
To check male fertility, the simplest, most informative test is a semen analysis report. It involves examining a semen sample to look for the presence of sperm cells, and see if they are normal in terms of motility, concentration, morphology, etc.
Assisted procreation, as any other medical treatment, requires that you rely on the professionalism of the doctors and staff of the clinic you choose. Obviously, each clinic is different. Get now your Fertility Report, which will select several clinics for you out of the pool of clinics that meet our strict quality criteria. Moreover, it will offer you a comparison between the fees and conditions each clinic offers in order for you to make a well informed choice.
In case too severe abnormalities are found through a semen analysis, such as azoospermia or cryptozoospermia, your doctor may ask you to do a blood test to check your hormone levels and try to find the cause of low sperm quality. Sometimes, sperm quality can be enhanced with a hormone treatment.
Azoospermia is defined as having zero sperm count in the ejaculate, while cryptozoospermia means that the male has a very low sperm count (below 100,000 sperm/ml).
According to Valeria Sotelo, MD:
The first fertility test done in males is a semen analysis. It is used to evaluate the sperm count, motility, and morphology. If the first semen analysis is normal, no other tests are required. But, if the results are abnormal, the man has to repeat it after 15 days.
Function of male sex hormones
Regulation of male sex hormones starts in the hypothalamus, a crucial part of the brain. Its function is to trigger the release of GnRH hormone, responsible for stimulating the pituitary gland to produce FSH and LH.
FSH and LH
The functions of both FSH and LH are interrelated between each other, since both affect the testicular function of males.
On the one hand, FSH regulates spermatogenesis (formation of new spermatozoa) in the seminiferous tubules of the testis. It affects the Sertoli cells, which are responsible for protecting and nourishing the cells that lead to sperm formation (spermatogonia). Moreover, FSH promotes the production of the testicular proteins that bind androgens (ABP).
On the other hand, LH triggers the production of testosterone by stimulating Leydig cells. Moreover, thanks to the action of ABP, testosterone can influence the testis and play its part on spermatogenesis.
Testosterone and dihydrotestosterone
Testosterone is the main male sex hormone. It is produced in the testicles due to the action of LH. It is also produced by the adrenal glands in both men and women, as well as by the ovaries in women, although in a small proportion.
5α-dihydrotestosterone (5α-DHT) derives from testosterone, that is, it is generated out of testosterone thanks to the action of 5α-reductases enzymes.
Both hormones are involved in the development of male sex characteristics, including body mass building, as well as facial and body hair growth.
As it happens with FSH and LH, prolactin is also produced by the pituitary gland, and is involved in male fertility to a large extent.
Prolactin is necessary for the well functioning of the male reproductive system, and affects the Leydig cells and testosterone production directly.
Male hormone reference ranges
Abnormal variations in the levels of the above mentioned hormones can affect spermatogenesis, either directly or indirectly. The following are the main hormones checked in males to find potential abnormalities:
Testosterone and dihydrotestosterone
Within the organism, testosterone can be free or linked to proteins. These are the normal testosterone levels in adult males:
- Free testosterone (bioavailable, not bound to proteins): 90-300 pg/mg.
- Total testosterone (free + bound to proteins): 270-1070 ng dl.
If the levels of testosterone are low, it can indicate that there exists some sort of abnormality that is affecting sperm production, like damage to the testes, and therefore male fertility.
On the other hand, if testosterone levels are high, it can be caused by a testicular tumor or androgen resistance, amongst other potential causes. Certain substances or drugs can increase testosterone levels as well.
Finally, normal levels of 5α-DHT are 30-85 ng/dl. Insufficient levels of 5α-reductases enzymes can prevent the synthesis of 5α-DH, causing pseudohermaphroditism (a person that has the secondary sex characteristics of a female but is a man from the genetic viewpoint).
FSH and LH
If your doctor suspects that your male sexual characteristics are abnormal, or that you have erectile dysfunction, low libido or infertility issues, he may request a blood test to examine your FSH and LH levels. These are the reference ranges:
- FSH: 1.0-12.0 mIU/ml.
- LH: 2.0-12.0 mIU/ml.
Too elevated levels of FSH and/or LH may indicate primary testicular failure (PTF), which can be caused by a wide range of causes, including an infection, trauma, chemotherapy…
Conversely, low levels indicate hypothalamic dysfunction or abnormalities in the pituitary gland.
Normal prolactin levels must be between 2.5 and 17 ng/ml (53-360 mIU/l). If they are above this reference range, it can indicate any of the following abnormalities:
- Low testosterone levels
- Sexual dysfunction
- Gynecomastia (abnormal growth of mammary glands)
- Pituitary tumor
Prolactin levels can be checked to do a follow-up in the case of male with low testosterone levels.
FAQs from users
My hormone levels are normal but I have azoospermia. Is it normal?
Yes, it is a possibility. When hormone levels are normal but a man has azoospermia, it is due to other causes that affect sperm production or the expulsion of sperm to the exterior.
In the latter case, this sperm disorder is called obstructive azoospermia. In some cases, sperm can be retrieved with a testicular biopsy.
However, one should keep in mind that finding the cause of infertility, whether in the man or the woman, is not possible in all cases.
What treatment options do I have for abnormal testosterone levels?
Artificial testosterone can be administered through different routes:
- Intramuscular injection: there exist different types of synthetic testosterone that can be administered intramuscularly. Propionate remains for a reduced time period in the body, so it has to be administered every 2-3 days. Testosterone enanthate and cypionate can be injected every two weeks (dose of 200 mg). Conversely, testosterone undecanoate can be administered every 12-15 weeks (1000 mg).
- Transfermal (patch): it can be administered in the form of a gel or cream daily, in the form of patches or implant.
- Oral (pills): this is the least common of all routes, since it is detrimental for the liver (hepatic toxicity).
Even though artificial testosterone can have many benefits, like muscle development or secondary male characteristics, one should keep in mind that, as any other medication, it can have some side effects. Always follow your doctor’s instructions before taking this type of medications.
Suggested for you
In addition to an hormone test, there are other tests a man can undergo to learn more about his fertility. If you are interested in delving deeper into them, we recommend that you have a look at this guide: Male Fertility Testing – How Do You Know if You Are Infertile?
The most common, informative of all male fertility tests is, as we explained above, the semen analysis (SE). We recommend that you get more info on this test here: What Is a Semen Analysis Report? – Purpose, Preparation & Cost.
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