The risks of testosterone replacement therapy are of interest to many men as the popularity of hormonal therapies increase.
Worldwide the sales of medical testosterone saw a 12-fold increase from 2000 to 2011. And this growth is not without its reasons. There is a massive difference in the way a testosterone deficient man feels about his life compared to how he would feel with healthy high testosterone levels. (1)
Testosterone is the primary male hormone in our bodies. It has many vital functions such as promoting muscle and bone formation as well as regulating mood and energy levels.
A little less than ten years ago I managed to crash my endocrine system and testosterone levels. This was a consequence of too much training, not enough food and simultaneous work stress. After some tests, my doctor assigned me to testosterone replacement therapy.
After a few months of doing the exogenous testosterone and reading up everything I could find on the subject, I decided to quit the treatment. Concern about infertility and other testosterone therapy risks combined with the headaches I got from the testosterone made me focus on natural ways to boost my T production.
Despite my choice, testosterone replacement therapy may be a good choice, if it is used to correct a genuine testosterone deficiency caused by a disability in the gonads or in the brain. Studies have found that correcting low testosterone levels leads to increased muscle mass, stronger bones and a better sense of well-being. (2)
Thousands, if not millions of men are considering getting a testosterone prescription each year. In this article, I wanted to answer the three most common questions about testosterone replacement therapy risks.
Does testosterone replacement therapy cause infertility?
Testosterone Replacement Therapy is indeed a replacement therapy.
When the treatment starts, a man’s body will have both the exogenous testosterone and the self-produced testosterone running through his veins.
However, after a few months of testosterone administration, the body’s own testosterone production in the testicles will have been suppressed to almost zero.
This is a result of the hormonal feedback loop that regulates testosterone levels. The feedback loop is controlled by the hypothalamus and the pituitary gland in the brain. As the hypothalamus detects high testosterone levels in the blood it will reduce the production of gonadotropin-releasing hormone (GnRH).
Normally GnRH will stimulate the pituitary to release luteinizing hormone (LH), which controls testosterone levels, and follicle stimulating hormone (FSH), which controls sperm production in the testicles. The production of all of these hormones in the feedback loop will be suppressed if testosterone is brought into the blood stream via injections or gels.
So, not only does the therapy halt the testosterone production in the testicles, it will also bring down the sperm production and possibly cause infertility. For this reason, testosterone has also been suggested as a contraceptive agent in men.
The contraceptive efficacy of testosterone has been examined in two large Chinese studies. A long-acting testosterone injection (such as Nebido) caused infertility in over 90 % of the men who enrolled in the studies. (1) (2)
In an earlier multi-location study, a short-acting once per week administered testosterone injection resulted in infertile sperm levels in 157 men out of 271 study participants. This study was carried out simultaneously in ten different countries. (3)
According to these and other trials, the subjects sperm production will usually get back to baseline levels after ending testosterone therapy. However, it will take 6 – 24 months before the sperm concentration is fully recovered. (4) (5) (6)
Long-term testosterone replacement therapy causes temporary infertility for the duration of the treatment for most men.
Does testosterone replacement therapy increase the risk for prostate cancer
As the popularity of TRT has grown, one of the biggest questions regarding testosterone replacement therapy risks is whether the treatment increases cancer incidence. Especially prostate cancer, which is the most common cancer among men in most countries, has been of concern. (1)
Several studies have been investigating the connection between testosterone replacement therapy and prostate cancer. On 2005, a meta-analysis of 19 previous studies was published in The Journals of Gerontology. The analysis found that the incidence of prostate cancer was not higher than normal in men treated with testosterone. (2)
The risk of prostate cancers does not seem to increase with long-term TRT either. 1365 men receiving TRT were monitored for up to 20 years in an English study. The prostate cancer rate among the men was found to be equivalent to that expected in the general population. (3)
In a recent Swedish study, the medical records of more than 250 000 men were surveyed for prostate health. The researchers found that men prescribed testosterone had no increase in the risk of prostate cancer and, in fact, had a reduced risk of aggressive forms of the disease. This might be caused by better screening and monitoring of TRT patients compared to non-patients. (4)
Testosterone replacement therapy does not seem to increase the risk of prostate cancer.
Does testosterone replacement therapy increase the risk for cardiovascular disease
The most common accepted testosterone therapy side effect is the increase in hematocrit, which indicates the volume of red blood cells in blood. In addition to hematocrit, testosterone also leads to an increase in hemoglobin by as much as 5 – 7 %. (1)
In theory, the rising hematocrit and the thickening of blood can lead to increased risks of heart attacks and strokes. (2)
In the recent past, testosterone has been associated with increased cardiovascular risk but the research on the subject is inconclusive. One study, published in The New England Journal of Medicine set out to investigate the ability of testosterone to increase mobility and muscle mass in elderly men. (3)
The trial had to be ended early as 23 men receiving testosterone suffered adverse cardiovascular events. At the same time in the placebo group, only 5 men had cardiovascular problems. During the study, the men were prescribed 100 mg of testosterone gel daily, which is double the conventional dosage.
As the popularity of TRT had rapidly increased, The Food and Drug Administration (FDA) stated in 2015 that neither the benefits nor safety of testosterone have been established in treating age-related low testosterone. (4)
This was partly a consequence of a 2014 study which surveyed cardiovascular risk in a three-month period following the onset of testosterone therapy. The results of the study showed a 2.2-fold risk of myocardial infarction in men over the age of 65 and a 3.4-fold risk in men over 75 years old. (5)
Despite these individual findings, the majority of testosterone therapy risk studies have not found an association between TRT and increased cardiovascular risk.
In five different meta-analyses, the data from dozens of previous studies has been combined to assess the occurrence of adverse cardiovascular events in men treated with testosterone. In four of the five analyses, testosterone treatment was not found to increase the risk of heart diseases. The remaining analysis found a link between increased cardiovascular risk and testosterone use. (6)
Testosterone replacement therapy may increase the risk of cardiovascular diseases in the beginning of the treatment in men over the age of 60. Some studies point to possible risk increase overall but the evidence is inconclusive.
Is TRT safe?
As with any medical treatment, testosterone replacement therapy can have both positive and negative health effects. The amount of benefits or disadvantages resulted from testosterone varies on an individual basis.
It is likely that testosterone therapy benefits are greatest in men who present a clear testosterone deficit in their blood tests and the cause of this deficiency is an internal problem, such as testicular failure (Primary hypogonadism) or brain-originated malfunction (Secondary hypogonadism).
On the other hand, if testosterone levels are borderline low and there might be external reasons for the deficiency, natural approaches for increasing testosterone levels are more reasonable than going straight to hormonal therapy.
In my case, it was the correct decision to go off the therapy. The underlying reasons for my testosterone deficiency were overtraining, insufficient diet and stress from work. In the end, it was quite easy for me to increase my testosterone production to manly-high levels by focusing more on rest and doing other corrections to my lifestyle.
The problem is that testosterone is often prescribed by some doctors too loosely without addressing lifestyle factors at all or not trying to correct the hormonal state in any natural way. This is odd because science has shown that for example, a common vitamin D deficiency may lower testosterone levels. And the same goes for zinc deficiency, sleep deprivation, and many other factors. (1) (2) (3)
So, that was it guys, my breakdown of the most common concerns about testosterone therapy risks. You can read more about the natural ways I used to boost my testosterone production throughout this blog!