Testicular cancer treatment—particularly orchiectomy (removal of the testicle) and chemotherapy—can have a long-term impact on a man’s hormonal balance. One of the more common consequences is reduced testosterone levels, known as hypogonadism. In some patients, this manifests as fatigue, decreased libido, slower recovery, loss of muscle mass, or a decline in overall well-being (dissatisfaction, nervousness, but also, for example, sudden sweating). Long-term follow-up studies of testicular cancer patients show that hormonal and sexual difficulties after treatment are not uncommon, affecting about 10–20% of patients, and deserve attention even after successful treatment of the disease.
Therefore, it is very important to attend regular check-ups with your oncologist, to talk openly about your health, and, if you begin to experience any of these symptoms, to request regular monitoring of your blood testosterone levels—as symptoms may appear later after treatment.
Why testosterone levels may drop after treatment
Testosterone is primarily produced in the Leydig cells of the testicles. Although the remaining testicle can usually take over the function after one is removed, it does not always do so completely. If its reserve is weaker or if it was already affected in some way before treatment, testosterone levels may be lower. Furthermore, chemotherapy can damage not only the cells involved in sperm production but also the testicle’s hormonal function. In some men, this leads to elevated LH (luteinizing hormone) levels after treatment, which is a signal that the body is trying to stimulate the testicle to produce more testosterone, but this may no longer be sufficient.
How Natural Testosterone Production Works
The body does not produce testosterone randomly. It is regulated by the hypothalamus–pituitary–testes axis (see figure below). The hypothalamus in the brain sends a signal to the pituitary gland, which releases the hormones LH (luteinizing hormone) and FSH (follicle-stimulating hormone), which in turn stimulate the testicles. LH promotes testosterone production, and FSH contributes to sperm production. This system operates on a feedback principle: if there is enough testosterone, the brain reduces stimulation; if there is too little, it increases stimulation.
If this feedback mechanism fails, “external assistance” is required, meaning the administration of testosterone prescribed by a urologist.
What happens when testosterone is supplied externally
If a man begins taking exogenous testosterone, for example in the form of a gel or injections, the body receives a signal that there is enough testosterone. The brain therefore reduces the production of LH and FSH. This means that the testicles receive less stimulation and begin to produce less of their own testosterone. This is precisely why, in testosterone therapy, it is often said that “the body’s own production shuts down.” Exogenous testosterone (“from an external source”) can improve symptoms of low testosterone, but at the same time it suppresses the natural functioning of the hormonal axis.
This is especially true for injections, which almost completely suppress endogenous production. Both the gel and injections suppress the natural hormonal axis. The main difference is that the gel leads to more stable levels, while injections cause more significant fluctuations.
Please note that it is not always possible to use it. In some cases, the injectable form may be more practical or effective
Why this can reduce fertility
Normal testosterone levels in the blood alone are not sufficient for sperm production. A high concentration of testosterone directly in the testicles is also necessary. When testosterone comes from an external source and LH and FSH levels drop, intratesticular testosterone—that is, testosterone directly in the testicles—also decreases. This can significantly suppress spermatogenesis (the process of sperm production in the testicles) and, in some men, even stop it completely. This is one reason why experts do not recommend exogenous testosterone for men who are currently trying to conceive.
Is there a difference between the ointment/gel and the injection?
Yes, but not in the sense that one form protects fertility and the other does not. Both forms deliver testosterone externally, and both can suppress the natural hormonal axis (see the figure above). The difference lies mainly in the delivery profile. A gel or patch delivers testosterone more gradually, while injections often produce higher and more pronounced levels. Available data show that even the gel can almost completely suppress gonadotropins—namely LH and FSH—though this occurs mainly after injections. Simply put: injections may have a “stronger” or more pronounced effect, but the gel is not a neutral form from a fertility perspective either.
So when should you be on the lookout?
After testicular cancer treatment, it makes sense to consider low testosterone, especially if you experience prolonged fatigue, low sex drive, decreased performance, low mood, muscle loss, or trouble concentrating. However, these symptoms may have other causes, so a subjective feeling alone is not enough. A laboratory testosterone test is important, ideally supplemented with LH, FSH, and other hormonal parameters as needed. Patients should actively ask about this if they experience any of these symptoms, as after cancer treatment, attention is often focused primarily on disease recurrence and less on quality of life following treatment.
There are other options besides exogenous testosterone
A healthy lifestyle—enough sleep, exercise, a nutritious diet, and overall vitality—can, especially in cases of minor fluctuations, help restore testosterone production without further intervention.
What’s important to remember
Low testosterone following testicular cancer treatment is a real problem that can affect energy, sexuality, mood, and physical condition. Therefore, exogenous supplementation may be appropriate to “kickstart” recovery after treatment and return levels to normal, and ideally lead to long-term discontinuation and a return to natural or endogenous production.
At the same time, however, exogenous testosterone is not automatically the best solution for everyone. If a man is planning to have a child, such treatment may reduce or completely halt sperm production. Therefore, hormonal therapy following testicular cancer should always be addressed on an individual basis, ideally with a urologist, andrologist, or endocrinologist who understands the connections between testosterone, fertility, and the consequences of cancer treatment.