It is recommended that physicians screen for prostate cancer with a digital rectal exam and prostate-specific antigen (PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy. On January 31, 2014, reports of strokes, heart attacks, and deaths in men taking FDA-approved testosterone-replacement led the FDA to announce that it would be investigating the issue. A postmarketing analysis by the manufacturer of Aveed (testosterone undeconate injection) found that POME occurred at a rate of less than 1% per injection per year for Aveed. 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. Breast cancer is said by some sources to be an absolute contraindication of testosterone therapy, but androgens including testosterone have also actually been used to treat breast cancer. Testosterone has been marketed for use by oral, sublingual, buccal, intranasal, transdermal (patches), topical (gels), intramuscular (injection), and subcutaneous (implant) administration. In addition, testosterone binds to and activates membrane androgen receptors (mARs) such as GPRC6A and ZIP9. Testosterone therapy is sometimes combined with an aromatase inhibitor for men with secondary hypogonadism who wish to conceive children with their partners. Aromatase inhibitors like anastrozole prevent the conversion of testosterone into estradiol by aromatase. In addition to the prevention of testosterone conversion into DHT, 5α-reductase inhibitors also prevent the formation of neurosteroids like 3α-androstanediol from testosterone, and this may have neuropsychiatric consequences in some men. Androgens like testosterone are teratogens and are known to cause fetal harm, such as producing virilization and ambiguous genitalia. However, the association between testosterone supplementation and the development of prostate cancer is unproven. Testosterone in the presence of a slow-growing prostate cancer is assumed to increase its growth rate. Testosterone gel is typically applied daily and absorbed directly through the skin, providing stable testosterone levels with less frequent hormonal peaks compared to some injectable forms. Tell your health care provider if you have any worsening prostate symptoms, such as having a hard time peeing or a weak flow, more frequent peeing, or having an urgent need to pee. Topical testosterone can worsen symptoms of BPH or may increase the risk of prostate cancer. Keep all appointments with your health care provider to check your blood. Call your health care provider right away if you have any of the following symptoms. Call your health care provider right away if you have any of the following symptoms of liver damage. To allow the therapy to take full effect, healthcare providers typically wait 30 days after you start TRT to check your testosterone levels. Key segments include prescription gels for testosterone replacement therapy, primarily used in men with low testosterone levels. Due to their possible health risks, it’s important to follow your healthcare provider’s instructions for taking the medication. The Japan testosterone gel market is primarily driven by North America, particularly the United States, where the demand for hormone replacement therapy is significant. If you have low testosterone symptoms, talk to your doctor about ways to boost levels such as hormone replacement therapy. A review of dozens of clinical trials showed that DHEA supplements do increase blood testosterone levels in men and women. In February 2025, the US Food and Drug Administration (FDA) specified label changes for products containing testosterone. Another approach being investigated is the detection of the administered form of testosterone, usually an ester, in hair. A number of methods for detecting testosterone use by athletes have been employed, most based on a urine test. This has proven contentious, with the Court of Arbitration for Sport suspending the IAAF policy due to insufficient evidence of a link between high androgen levels and improved athletic performance. Anabolic–androgenic steroids (AAS), including testosterone and its esters, have also been taken to enhance muscle development, strength, or endurance. Hormone supplements cause the endocrine system to adjust its production and lower the natural production of the hormone, so when supplements are discontinued, natural hormone production is lower than it was originally.citation needed Unmodified testosterone was also formerly available for intramuscular injection but was discontinued. In the US in the 2000s, companies and figures in the popular media have heavily marketed notions of "andropause" as something parallel to menopause; these notions have been rejected by the medical community. Intramuscular testosterone undecanoate was not introduced in Europe and the United States until much later (in the early to mid 2000s and 2014, respectively). There are no known interactions between topical testosterone and foods or drinks. People who can breastfeed are not usually prescribed topical testosterone. If you are pregnant or may become pregnant, you should avoid contact with the area where topical testosterone has been applied. People who can become pregnant are not usually prescribed topical testosterone. This will help them know if topical testosterone is right for you.
