Description – Testosterone Undecanoate

Testosterone undecanoate is a long-acting form of the primary male sex hormone, essential for the development and maintenance of primary and secondary sexual characteristics. Testosterone plays a key role in the development of male reproductive tissues, such as the testes and prostate, and also contributes to the overall health of both sexes, supporting bone density, muscle mass, and physical and mental well-being.

Inadequate testosterone levels in men can cause numerous problems, including decreased muscle mass, bone fragility, fatigue, and a decreased quality of life. Thanks to its marked anabolic properties, testosterone undecanoate promotes increased muscle mass, stimulates protein synthesis, accelerates physical recovery, and improves muscle glycogen stores. For this reason, testosterone-based drugs are used both in hormone replacement therapy for men with age-related hypogonadism and as a cornerstone of hormonal protocols for athletes.

Mechanism of action

Testosterone undecanoate works by binding to androgen receptors in target tissues. A portion of testosterone can be converted to dihydrotestosterone (DHT) via the enzyme 5α-reductase; DHT has up to five times greater affinity for androgen receptors than testosterone. Activation of these receptors induces changes in gene expression at the cellular level, responsible for androgenic and anabolic effects.

Testosterone can also undergo aromatization, converting to estrogen. Estrogens play an important role in the feedback loop of the hypothalamic-pituitary-gonadal axis, influencing endogenous testosterone production when exogenous testosterone such as testosterone undecanoate is administered.

Medical use

Testosterone is included in the World Health Organization’s List of Essential Medicines, confirming its therapeutic importance. Testosterone undecanoate is used in the treatment of male hypogonadism, hormone replacement therapy (TRT), gender dysphoria, and specific clinical conditions such as some types of breast cancer.

As we age, the natural decline in testosterone production often makes replacement therapy necessary to maintain physiological hormone levels and preserve health, vitality, and quality of life. Testosterone undecanoate, thanks to its long half-life, allows for gradual and stable release of the hormone over time.

Numerous studies also indicate that testosterone affects cognitive functions such as mood, attention, memory, and spatial ability. Low testosterone levels have been associated with an increased risk of cognitive decline. In both sexes, testosterone contributes significantly to general well-being and the prevention of various diseases.