Description

Testosterone is the primary sex hormone in humans, playing a crucial role in the development of male and female reproductive tissues, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, body hair growth, and overall well-being. Testosterone is essential for maintaining health and preventing conditions like osteoporosis. In men, insufficient levels of testosterone can lead to frailty and bone loss. Testosterone is not only used by athletes for muscle building but also has medical applications for conditions such as gender dysphoria, male hypogonadism, and certain types of breast cancer.

Mechanism of Action

Testosterone binds to androgen receptors and serves as a precursor to another biologically active androgen called dihydrotestosterone (DHT), which is formed through the action of the enzyme 5α-reductase on testosterone. DHT has a higher affinity for androgen receptors compared to testosterone. These hormones bind to androgen receptors, triggering changes in gene activity and mediating androgenic effects. Testosterone can also be converted to estrogen through the process of aromatization. Estrogens, rather than testosterone, predominantly activate feedback mechanisms and suppress the secretion of endogenous testosterone when exogenous testosterone is administered.

Medical Use

Testosterone is included in the World Health Organization's list of essential medicines, highlighting its importance in basic healthcare. It is used as a medication for the treatment of gender dysphoria, male hypogonadism, and certain types of breast cancer. Hormone replacement therapy (HRT) or testosterone replacement therapy (TRT) may be necessary to maintain testosterone levels within the normal range, especially as men age and experience declining testosterone production. Testosterone replacement therapy can improve well-being, sexual function, and overall body composition.

Testosterone for Seniors

Men over the age of 35 who experience a decline in well-being are often recommended to have their testosterone levels tested. If levels are below 12 nmol/l, hormone replacement therapy may be offered. This approach has several positive effects, including improvements in body composition (reduced fat, increased muscle mass), rejuvenated sexual function, and an overall reversal of the negative effects associated with androgen deficiency. Regular monitoring of lipid profiles, blood parameters, estradiol, and prolactin levels is essential. Additionally, for individuals desiring to have offspring, specific therapy with gonadotropins may be required.

Testosterone in Sports

The main advantage of testosterone in sports is its ability to increase muscle mass and strength. It has both anabolic and androgenic effects. Androgens interact with androgen receptors, leading to changes in gene expression and protein synthesis. Testosterone can also promote water retention, joint health, regeneration processes, and enhanced oxygen-carrying capacity in the blood. Typical dosages in sports range from 250 to 500 mg per week, with adjustments based on an athlete's body weight. Testosterone cycles usually last 8 to 10 weeks, followed by post-cycle therapy. Regular monitoring of estradiol levels and the use of aromatase inhibitors are important to manage potential estrogenic side effects.