Testosterone undecanoate is a medicine used for medicinal purposes and is also used by bodybuilders and other athletes to increase the level of the male hormone in the body. Testosterone undecanoate is available as oral tablets.
Features of the drug in oral form
Almost all of the common forms of testosterone on the pharmaceutical market come in the form of an oily solution for injection. The fact is that when the unchanged molecule of this hormone is absorbed from the digestive tract, it is inevitably destroyed by special enzymes in the liver. Therefore, in order to produce a stable form of testosterone in tablets, it was necessary to modify its molecule in such a way that it was well absorbed in the intestine (easily penetrated through the mucous membrane) and at the same time not destroyed. in the liver
The first testosterone tablets – methyltestosterone (trade names – Androral, Metandren, Testoral, etc.) were developed for the treatment of breast cancer in women in the middle of the last century. However, this drug has not been widely used in both bodybuilding and medicine due to serious side effects on the liver.
Pharmacokinetics: absorption and elimination after administration
In the early 1980s, a tablet (more specifically encapsulated) preparation was developed – testosterone undecanoate (testosterone undecanoate), which is now also available in the form of injections under the brand name Nebido. This form is also known under the brand names Virigen, Andriol, and Androxon.[2] The capsules contain 40 mg of the active ingredient dissolved in oil.
Studies have shown that Testosterone Undecanoate does not have toxic effects on the liver, because when it is absorbed through the digestive tract, it enters the lymph (rather than the bloodstream), the flow of which enters the common lymphatic channel to the common circulatory system. , thus avoiding the liver. . In the body, undecanoate is converted to dihydrotestosterone, an active metabolite of testosterone, which means that this substance is actually a prohormone.
Due to the fact that dihydrotestosterone does not undergo aromatization, it does not cause an increase in the level of female sex hormones – estrogen, and therefore does not lead to the development of gynecomastia and water retention in the body. Furthermore, it has been found that testosterone tablets (Androxon or Andriol) do not significantly suppress endogenous testosterone production (excreted in the testes).
It seems that the tablet version of the hormone has no significant drawbacks and claims to be the best anabolic agent, but in practice Testosterone Undecanoate turns out to be quite a weak androgenic drug. Athletes who have used it in their training practice see only a slight increase in muscle mass even when using high doses of the drug.
Pharmacokinetics: absorption and elimination after administration
The drug was found to have a fairly low bioavailability, around 7%. In addition, treatment with testosterone undecanoate has been shown to produce a significant increase in libido (at admission) and frequent erections. A few days after the course, these indicators, like other androgenic steroids, decrease due to the suppression of endogenous secretion of male sex hormones.
For good muscle building results, Testosterone pills should be combined with a steroid like Nandrolone. The combination of Testosterone Undecanoate + Nandrolone is very effective and has almost no side effects. In general, this drug is not the preferred choice in bodybuilding for muscle mass or definition, or weightlifting for strength.
Pharmacological effect
Testosterone undecanoate is a male sex hormone with androgenic activity. It contributes to the development of the genitals and the development of secondary sexual characteristics in men. In hypogonadism of various etiologies, exogenous testosterone compensates for the lack of endogenous hormone.
Testosterone also has an anabolic effect: it stimulates protein synthesis in the body, accelerates bone calcification. It causes a delay in the body of nitrogen, potassium, calcium, sulfur, phosphates, as well as sodium, chlorine and water. Stimulates erythropoiesis. In women, testosterone inhibits pituitary gonadotropin function, ovarian and breast function, and endometrial atrophy.
Indications for use
In medicine, the medicine is used to solve the following problems:
- Establish substitution therapy for primary and secondary hypogonadism in men.
- Treatment of androgen deficiency osteoporosis.
- Breast cancer, abnormal uterine bleeding in postmenopausal women.
- Menopausal disorders in women (usually in combination treatment).
- Treatment of refractory anemia in men and women.
Bodybuilding application
Testosterone undecanoate is actively used by athletes to build muscle mass and strengthen bones. This is facilitated by its properties of stimulating protein synthesis and accelerating the calcification of bone tissue.
Bodybuilding application
Special Instructions
It is used with caution in patients with hepatic and / or renal impairment, heart failure, hypertension, coronary heart disease, migraine and epilepsy. Liver function should be monitored during long-term treatment. Careful monitoring of blood and calcium levels is required in patients with breast cancer, kidney cancer, lung cancer and bone metastases.
When treating prepubertal adolescents, systematic monitoring is recommended to avoid premature closure of the epiphyses of the legs and early puberty.