What are Aromatase Inhibitors?
Aromatase inhibitors (AIs) are a group of drugs used to treat some types of breast cancer in postmenopausal women. They function by blocking the enzyme aromatase, which converts androgens (male hormones) to estrogens (female hormones) [1, 2, 3, 4, 5].
Aromatase inhibitors bind to the aromatase enzyme and prevent it from turning androgens into estrogens. This process reduces the amount of estrogen in the body, and this helps with hormone-receptor-positive breast cancer particularly well. It is a cancer which relies on estrogen to grow, and AIs lower estrogen to stop the growth and proliferation of cancer cells [6, 7, 8, 9, 10].
Depending on their chemical structure, there are two types of aromatase inhibitors: steroidal and non-steroidal. There are irreversible steroidal inhibitors like exemestane that attach to the aromatase enzyme highly selectively. Non-steroidal inhibitors — anastrozole, letrozole — are reversible and highly compatible with the aromatase enzyme [5, 6].
AIs have been applied to ovulation-inducing, endometriosis and other endocrine-regulated diseases, as well as to breast cancer. However, excessive use of aromatase inhibitors may lead to osteoporosis due to estrogen depletion. Bone mineral density screening should be conducted in women who are being treated with long-term aromatase inhibitors [11, 3].
What is TRT?
The medical treatment Testosterone Replacement Therapy (TRT) is mainly utilised to treat low testosterone levels, often caused by old age or medical issues. It’s a drug that releases exogenous testosterone to get testosterone levels in the body back on track [12, 13, 14].
What Does TRT Do?
TRT has several therapeutic effects. It is commonly administered to people with hypogonadism, where the testes don’t produce enough testosterone. When that is the case, TRT can increase sexual function, sperm size and count, and levels of other hormones that interact with testosterone, such as prolactin [12].
TRT is also able to control excessive testosterone due to many conditions like autoimmune disorders, genetic disease, infection of sex organs, undescended testicles, cancer radiation and sex organ surgeries [12].
As a medical device, TRT is also in high demand for non-medical purposes like:
- Increasing sexual performance
- Increase energy
- Gain muscle mass for bodybuilding [12].
TRT can be beneficial, but it can have side effects and dangers, including:
- Polycythemia,
- Cardiac and liver dysfunction,
- And may be contraindicated in men with untreated prostate and breast cancer [13, 14].
Risks and Sife Effects of TRT
Men who have low testosterone usually get treated with testosterone replacement therapy (TRT). Yet it is essential to know that this treatment also has a risk.
Chest pain is one of the dangers of TRT. This can be a sign of heart disease, which can be made worse by TRT [12]. However, note that there is mixed evidence on TRT causing cardiovascular issues [19].
Breathing problems are another possible side effect of TRT. They are an expression of several diseases, such as heart and lung diseases, that TRT may worsen [12].
Speech impediments are also possible symptoms of neurological disorders and may or may not be influenced by TRT [12].
TRT can cause low sperm count, too. This affects fertility and is a significant consideration for males who wish to conceive [12].
The other risk of TRT is polycythemia vera, which causes a surplus of blood cells [12].
TRT can also lower HDL, or "good" cholesterol, leading to heart disease [12].
Inflammation of the hands or legs may be caused by many medical conditions, such as heart disease and kidney disease, which TRT can cause [12].
TRT could also put the patient at greater risk of stroke – a fatal illness caused by a disruption in blood supply to the brain [12].
Another risk factor is benign prostatic hyperplasia, a larger prostate. It may have several urinary manifestations and may be triggered by TRT [12].
Sleep apnea (a pattern of sleep inability that stops breathing between breaths) can be a risk factor for TRT [12, 15].
Acne or similar skin eruptions can affect TRT [12].
Another risk factor could be deep vein thrombosis, a blood clot in a deep vein [12].
Last but not least, TRT can also cause pulmonary embolism, a lung-specific condition in which one or more arteries get narrowed [12].
Are Aromatase Inhibitors Bad on TRT?
Aromatase inhibitors (AIs) are medications that inhibit the conversion of testosterone into estrogen and boost the level of testosterone in the body. They have been prescribed for different disorders, such as testosterone replacement therapy (TRT) [16, 9]. But are they "bad" or damaging if taken alongside TRT? That’s a question that relates to multiple factors.
Aromatase inhibitors do raise blood testosterone, but other measures of health don’t seem to be as favourable. In some studies, for example, there is very little change in body composition and physical activity after aromatase inhibition. There was also an increase in spinal Bone Mineral Density (BMD) in some trials, which may progress into osteoporosis [17].
Regarding side effects, AIs are responsible for joint pain, stiffness, and poor quality of life [16]. However, they have also been successfully applied to gynecomastia, a TRT side-effect, which might be helpful in some settings [11].
Regarding cardiovascular safety, no evidence exists that TRT raises cardiovascular risk [18]. But, it is still being determined if AIs could change this risk profile by adding them to TRT.
Though aromatase inhibitors may be valuable in conjunction with TRT, they also come with potential drawbacks, such as decreased bone mineral density and joint pain. This still needs to be researched in greater detail to get a good picture of how AIs' long-term effects and safety profile would play out under TRT.