Relative contraindications of testosterone include elevated prostate-specific antigen (PSA) in men with a high risk of prostate cancer due to ethnicity or family history, severe lower urinary tract symptoms, and elevated hematocrit (>50%). Side effects
Adverse effects may also include minor side effects such as oily skin, acne, and seborrhea, as well as loss of scalp hair, which may be prevented or reduced with 5α-reductase inhibitors. In women, testosterone can produce hirsutism (excessive facial/body hair growth), deepening of the voice, and other signs of virilization. Exogenous testosterone may cause suppression of spermatogenesis in men, leading to, in some cases, reversible infertility. Gynecomastia and breast tenderness may occur with high dosages of testosterone due to peripheral conversion of testosterone by aromatase into excessive amounts of the estrogen estradiol. Testosterone treatment, particularly in high dosages, can also be associated with mood changes, increased aggression, increased sex drive, spontaneous erections, and nocturnal emissions.Other side effects include increased hematocrit, which can require venipuncture in order to treat, and exacerbation of sleep apnea.The FDA stated in 2015 that neither the benefits nor the safety of testosterone have been established for low testosterone levels due to aging. The FDA has required that testosterone pharmaceutical labels include warning information about the possibility of an increased risk of heart attacks and stroke. They have also required the label include concerns about abuse and dependence.Injectable forms of testosterone can cause a lung problem called pulmonary oil microembolism (POME). Symptoms of POME include cough, shortness of breath, tightening of the throat, chest pain, sweating, dizziness, and fainting.
These metabolites, along with estradiol, may be involved in a number of the effects of testosterone in the brain, including its antidepressant, anxiolytic, stress-relieving, rewarding, and pro-sexual effects. Effects in the body and brain
The ARs are expressed widely throughout the body, including in the penis, testicles, epididymides, prostate gland, seminal vesicles, fat, skin, bone, bone marrow, muscle, larynx, heart, liver, kidneys, pituitary gland, hypothalamus, and elsewhere throughout the brain.