Androgen replacement therapy

Testosterone Replacement Therapy (TRT), also known as Androgen replacement therapy (ART), is a form of hormone therapy in which androgens, most often testosterone, are supplemented or replaced. It typically involves the administration of testosterone through injections, skin creams, patches, gels, pills, or subcutaneous pellets. ART is often prescribed to counter the effects of male hypogonadism.

ART is also prescribed to lessen the effects or delay the onset of normal male aging. However, this is controversial and is the subject of ongoing clinical trials.

As men enter middle age they may notice changes caused by a relative decline in testosterone: fewer erections, fatigue, thinning skin, declining muscle mass and strength, and/or more body fat. Dissatisfaction with these changes causes some middle age men to seek ART. Androgen deficiencies in women have also, as of 2001, been recognized as a medical disorder that can be treated with ART. As with men, symptoms associated with androgen deficiency are most prevalent with age, and androgen replacement therapy has been shown to help with symptoms of menopause.

Testosterone has many effects on the body, either when made by the body or when given as a hormone replacement. Testosterone has anabolic effects on muscle and bone, leading to increased muscle mass and bone density. It is also known to stimulate erythropoesis (red blood cell production). It is known to improve penile blood flow to help with erections and also improve sexual drive or desire.

Androgen replacement is the classic treatment of hypogonadism. It is also used in men who have lost the ability to produce androgens due to disease or its treatment. Testosterone replacement in men with hypogonadism has consistently shown to improve sexual function; including increases in libido and sexual activity. Erectile function was also shown to modestly improve in some studies of testosterone treatment for male hypogonadism, other studies did not show a benefit. Testosterone treatment in men with hypogonadism was shown to have modest improvements in physical activity, modest improvements in mood (but it did not improve mood in those with major depression), and some studies showed modest improvements in subjective energy levels and self reported physical fitness. Testosterone therapy was not shown to improve cognitive function in men with hypogonadism. Testosterone therapy was also shown to raise the hemoglobin (blood count) by 1 point in 33-50% of people, and increase bone density by up to 7% in the spine and hip, but the clinical significance of these changes is unclear.

The risks of diabetes and of testosterone deficiency in men over 45 (i.e., hypogonadism, specifically hypoandrogenism) are strongly correlated. Testosterone replacement therapies have been shown to improve blood glucose management. Still, "it is prudent not to start testosterone therapy in men with diabetes solely for the purpose of improving metabolic control if they show no signs and symptoms of hypogonadism."

Other studies have not shown a benefit in diabetes prevention or better diabetes control with testosterone therapy. One study showed testosterone therapy in older men with low testosterone not changing sugar levels or hemoglobin A1c (used as a marker of diabetes control, or for the diagnosis of diabetes) compared to placebo. In another trial from 2024, testosterone therapy for men with hypogonadism and prediabetes did not prevent the progression of prediabetes to diabetes and it did not improve diabetes control compared to placebo.

Androgen replacement is used in postmenopausal women: the indications are to increase sexual desire; and to prevent or treat osteoporosis. Other symptoms of androgen deficiency are similar in both sexes, such as muscle loss and physical fatigue. The androgens used for androgen replacement in women include testosterone (and esters), prasterone (dehydroepiandrosterone; DHEA) (and the ester prasterone enanthate), methyltestosterone, nandrolone decanoate, and tibolone, among others.