How do hormones affect male fertility and what treatments are available? 

Hormones play a key role in male fertility, and testosterone is only one part of a much larger system. The Hypothalamic–Pituitary–Gonadal (HPG) axis is a hormonal pathway that connects the brain and the testes. It controls sperm production and hormone levels. The brain releases signals that stimulate the testes to produce testosterone and support sperm development (O’Donnell et al., 2000). 

When this system is disrupted, fertility can be affected. Hypogonadism is a condition where the body does not produce enough testosterone or sperm. It can be caused by problems in the testes (primary hypogonadism) or in the brain (secondary hypogonadism). Identifying the cause is important because treatment depends on where the problem originates (Kumar et al., 2010). 

Doctors often use hormone levels to help diagnose the issue. For example, certain patterns of hormone levels can indicate whether the problem lies in the testes or the brain. 

One treatment option is human chorionic gonadotropin (hCG), which mimics a natural hormone and stimulates the testes to produce testosterone. This is particularly useful in men with secondary hypogonadism (Lee et al., 2018). 

Thyroid health also plays a role in fertility. Both overactive and underactive thyroid conditions can affect sperm production, sexual function, and hormone balance. For this reason, thyroid testing is often included in fertility assessments (Wdowiak et al., 2025). 

Some medications can help improve hormone balance without reducing sperm production. For example, anastrozole reduces oestrogen levels, which can help restore normal hormone signalling and improve testosterone levels (Shah et al., 2021). Another medication, clomiphene citrate (Clomid), increases the body’s natural production of fertility hormones, helping to boost both testosterone and sperm production (Wu et al., 2024). 

It is important to note that testosterone replacement therapy is usually avoided in men trying to conceive. This is because external testosterone can reduce the body’s natural hormone signals and stop sperm production (Crosnoe et al., 2013). 

In summary, male fertility depends on a complex hormonal system. Understanding and treating hormonal imbalances can improve fertility while preserving the body’s natural ability to produce sperm. 

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Lee JA, Ramasamy R. Indications for the use of human chorionic gonadotropic hormone for the management of infertility in hypogonadal men. Transl Androl Urol. 2018 Jul;7(Suppl 3):S348-S352. doi: 10.21037/tau.2018.04.11. PMID: 30159241; PMCID: PMC6087849. 

Wu YC, Sung WW. Clomiphene Citrate Treatment as an Alternative Therapeutic Approach for Male Hypogonadism: Mechanisms and Clinical Implications. Pharmaceuticals (Basel). 2024 Sep 18;17(9):1233. doi: 10.3390/ph17091233. PMID: 39338395; PMCID: PMC11435126. 

Kumar P, Kumar N, Thakur DS, Patidar A. Male hypogonadism: Symptoms and treatment. J Adv Pharm Technol Res. 2010 Jul;1(3):297-301. doi: 10.4103/0110-5558.72420. PMID: 22247861; PMCID: PMC3255409. 

Wdowiak K, Maciocha A, Waz J. Sexual functioning of women and men with thyroid diseases. Journal of Sexual and Mental Health. 2025;23:45–54. doi:10.5603/jsmh.105050. 

Crosnoe LE, Grober E, Ohl D, Kim ED. Exogenous testosterone: a preventable cause of male infertility. Transl Androl Urol. 2013 Jun;2(2):106-13. doi: 10.3978/j.issn.2223-4683.2013.06.01. PMID: 26813847; PMCID: PMC4708215.