The significance of a decrease in testosterone levels is debated and its treatment with replacement is controversial. The Food and Drug Administration (FDA) stated in 2015 that neither the benefits nor the safety of testosterone have been established in older men with low testosterone levels. Testosterone replacement therapy should only be started if low levels have been confirmed; in the US, this confirmation is not done about 25% of the time, as of 2015. Testosterone levels should also be monitored during therapy. Adverse effects Adverse effects of testosterone supplementation may include increased cardiovascular (CV) events (including strokes and heart attacks) and deaths, especially in men over 65 and men with pre-existing heart conditions. The potential for CV risks from testosterone therapy led the FDA to issue a requirement in 2015 that testosterone pharmaceutical labels include warning information about the possibility of an increased risk of heart attacks and stroke. However, the data are mixed, so the European Medicines Agency, the American Association of Clinical Endocrinologists, and the American College of Endocrinology have stated that no consistent evidence shows that testosterone therapy either increases or decreases cardiovascular risk. Other significant adverse effects of testosterone supplementation include acceleration of pre-existing prostate cancer growth; increased hematocrit, which can require venipuncture to treat; and, exacerbation of sleep apnea. Adverse effects may also include minor side effects such as acne and oily skin, as well as significant hair loss and/or thinning of the hair, which may be prevented with 5-alpha reductase inhibitors ordinarily used for the treatment of benign prostatic hyperplasia, such as finasteride or dutasteride. Exogenous testosterone may also cause suppression of spermatogenesis, leading to, in some cases, infertility.
Late-onset hypogonadism
Prepubertal hypertrichosis
Delayed puberty
Hypogonadotropic hypogonadism
Hypergonadotropic hypogonadism
Hypertelorism
Prognathism
Precocious puberty