Description

Testosterone serves as the primary sex hormone in humans, playing a crucial role in the development of male and female reproductive tissues, including the testes, prostate, and ovaries. It also promotes the development of secondary sexual characteristics such as increased muscle and bone mass and body hair in males. Testosterone is essential for overall health, well-being, and the prevention of osteoporosis in both sexes. Insufficient levels of testosterone in men can lead to abnormalities like frailty and bone loss. Testosterone possesses significant anabolic properties, including increased muscle mass, accelerated protein synthesis, enhanced recovery rate, and improved glycogen supply to muscles. It regulates numerous bodily processes, making it a vital hormone that is used not only by elderly individuals with age-related hypogonadism but also by athletes on steroid cycles as a foundation.

Mechanism of action

Testosterone binds to androgen receptors and serves as a precursor to dihydrotestosterone, a biologically active androgen that forms through the conversion of testosterone by the enzyme 5α-reductase. Dihydrotestosterone exhibits five times greater affinity for androgen receptors. These hormones cause structural changes in the receptors, which transmit signals to the cell nucleus, where androgenic effects occur through the modulation of specific DNA genes. Testosterone can be aromatized into estrogen through the action of aromatase. Estrogens, rather than testosterone, predominantly activate feedback mechanisms through the hypothalamus-pituitary-testes axis and suppress endogenous testosterone secretion in the presence of exogenous testosterone drugs.

Medical Use

Testosterone is included in the World Health Organization's list of essential medicines, which comprises vital medications needed in a basic healthcare system. Thus, the perception that it is solely an anabolic steroid for muscle enhancement is incorrect; it is a crucial hormonal drug. Testosterone is used medically for the treatment of gender dysphoria, male hypogonadism, and certain types of breast cancer. As testosterone levels decline with age in men, hormone replacement therapy (HRT) or testosterone replacement therapy (TRT) is necessary to maintain health and quality of life. HRT ensures that serum testosterone levels remain within the normal range. The decline in testosterone production associated with aging has sparked interest in androgen replacement therapy.

Mood, spatial ability, attention, memory, and other cognitive functions in humans are influenced by testosterone. Preliminary evidence suggests that low testosterone levels are a risk factor for cognitive decline and potentially Alzheimer's-type dementia.

In both sexes, testosterone contributes to overall health, well-being, and the prevention of osteoporosis. Insufficient levels of testosterone in men can lead to abnormalities such as frailty and bone loss. Testosterone treatment is also beneficial for adult men with age-related low testosterone levels who experience sexual dysfunction.

Testosterone for Seniors

Men over 35 who experience well-being issues are often advised to test their blood testosterone levels. If the levels are below 12 nmol/l, hormone replacement therapy is recommended. This decision offers several positive aspects. It improves body composition, reducing fat and increasing muscle mass. It revitalizes sexual function and has a rejuvenating effect on the body, reversing the negative effects of androgen deficiency. Regular monitoring of lipid profiles, clinical blood parameters, estradiol levels, and prolactin levels is crucial when using hormone replacement therapy. Natural gonadotropin production steadily decreases with HRT, so if fertility is desired, special therapy involving gonadotropins is necessary. Dosage selection for testosterone therapy should be done under the guidance of a healthcare professional and takes into account factors such as normal testosterone levels, current levels, body weight, body fat percentage, sex hormone-binding globulin (SHBG) levels, and the aromatization process.

Approximately, the dosages for replacement therapy are much lower than those used by athletes, ranging from 50 to 200 mg per week.

Testosterone in Sports

The primary advantage of testosterone in sports is its ability to increase muscle mass and strength. Alongside its anabolic effects, it also exerts a strong androgenic effect. Androgens enter cells and interact with androgen receptor (AR) proteins. This interaction causes a conformational change in the AR protein, activating it. Although the change is minor, it has significant effects as it enables AR to enter the nucleus and bind to DNA, resulting in gene activation.

Rapid weight gain associated with testosterone use is primarily due to water retention through sodium retention and estrogenic effects. Testosterone can help alleviate joint problems, pain, and discomfort in the shoulders and knees, but other compounds like nandrolone and growth hormone may be preferred for this purpose. Testosterone promotes the body's regeneration processes, enhances overall energy and desire to exercise, and prevents overtraining. It increases the oxygen-carrying capacity of the blood and stimulates nitric oxide production, leading to a satisfying pump during training sessions.

The recommended dosage for sports purposes is typically 250-500 mg per week, with a tendency to increase the dosage as the athlete's body weight increases. Testosterone cycles usually last 8-10 weeks, followed by a 2-3 week post-cycle therapy. In some cases, testosterone is used for longer durations. Professional athletes at a high level may use up to 2000 mg per week, although further dosage escalation is pointless and only increases the risk of side effects.

To mitigate the development of estrogenic side effects resulting from aromatization, it is advisable to regularly monitor estradiol levels and employ aromatase inhibitors if necessary. It is optimal to test estradiol levels before and during the use of aromatase inhibitors to assess their effectiveness and determine the appropriate dosage. It is strongly recommended to entrust dosage selection to professionals. However, the following information is provided for reference.

How to Use

In the realm of strength sports, Testosterone Undecanoate is not widely utilized due to its undefined and insufficient effect, as well as its extended duration of action. However, it finds more application in clinical andrology as hormone replacement therapy for patients with age-related androgenic deficiency. To maintain stable serum testosterone levels within the normal range without significant fluctuations, injections are administered every 3 months after an initial loading dose in a 6-week interval (although in practice, more frequent administrations, every 4-5 weeks, are common).

Pharmacokinetic studies have shown that testosterone levels return to the physiological range within 3 days after the initial administration. When injections are spaced approximately 10-12 weeks apart, testosterone concentrations remain consistently within the normal range. The initial dosing interval can be reduced to six weeks to achieve steady-state testosterone levels more rapidly.

The following recommendations should be considered when administering Testosterone Undecanoate:

Administer the first and second doses of Testosterone Undecanoate with a 4-6 week interval between them.

Subsequently, maintain an injection interval of approximately 10-12 weeks.

Effects

Increased muscle mass
Involvement in the development of male genital organs and secondary sexual characteristics, such as a deep voice, masculine facial features, and male-pattern hair growth
Promotion of spermatogenesis and male behavior, including sexual drive, aggressiveness, and decisiveness
Enhanced muscle mass
Fat burning
Increased strength
Elevated libido
Reduction of blood cholesterol levels
Lowered risk of heart ischemia and coronary heart disease
Stimulation of erythropoiesis and redistribution of subcutaneous fatty tissue towards a male-like pattern
Influence on nitrogen and phosphorus metabolism