For this reason, and due to the unknown health effects and safety of testosterone therapy, its use may be inappropriate. In 2003, the FDA rejected Intrinsa, a 300 µg/day testosterone patch for the treatment of sexual dysfunction in postmenopausal women. The reasons cited were limited efficacy (about one additional sexually satisfying event per month), concerns about safety and potential adverse effects with long-term therapy, and concerns about inappropriate off-label use. It appears that in women, rather than testosterone, estradiol may be the most important hormone involved in sexual desire, although data on the clinical use of estradiol to increase sexual desire in women is limited.There are no testosterone products approved for use in women in the United States and many other countries. There are approved testosterone products for women in Australia (where it is considered a drug of dependence, medicines that are subject to misuse and trafficking.) and some European countries. Testosterone pellet implants are approved for use in postmenopausal women in the United Kingdom. Testosterone products for men can be used off-label in women in the United States. Alternatively, testosterone products for women are available from compounding pharmacies in the United States, although such products are unregulated and manufacturing quality is not ensured. Available forms
Testosterone has been marketed for use by oral, sublingual, buccal, intranasal, transdermal (patches), topical (gels), intramuscular (injection), and subcutaneous (implant administration. It is provided unmodified and as a testosterone ester such as testosterone cypionate, testosterone enanthate, testosterone propionate, or testosterone undecanoate, which act as prodrugs of testosterone.
Transgender men
To take advantage of its virilizing effects, testosterone is administered to transgender men and other transmasculine individuals as part of masculinizing hormone therapy, titrated to clinical effect with a "target level" of the average males testosterone level. Women
Testosterone therapy is effective in the short-term for the treatment of hypoactive sexual desire disorder (HSDD) in women. However, its long-term safety is unclear. Because of a lack data to support its efficacy and safety, the Endocrine Society recommends against the routine use of testosterone in women to treat low androgen levels due to hypopituitarism, adrenal insufficiency, surgical removal of the ovaries, high-dose corticosteroid therapy, or other causes. Similarly, because of a lack of data to support its efficacy and safety, the Endocrine Society recommends against the use of testosterone in women to improve general well-being, to treat infertility, sexual dysfunction due to causes other than HSDD, or to improve cognitive, cardiovascular, metabolic, and/or bone health.A 2014 systematic review and meta-analysis of 35 studies consisting of over 5,000 postmenopausal women with normal adrenal gland function found that testosterone therapy was associated with significant improvement in a variety of domains of sexual function. These domains included frequency of sexual activity, orgasm, arousal, and sexual satisfaction, among others. Women who were menopausal due to ovariectomy showed significantly greater improvement in sexual function with testosterone relative to those who had normal menopause. In addition to beneficial effects on sexual function, testosterone was associated with unfavorable changes in blood lipids.