Proviron is an active androgen intended for oral administration. The presence of a methyl group at position C-1 determines the special properties of this steroid which, unlike testosterone and all its derivatives used for androgen therapy, is not metabolized to estrogen.

This difference explains the fact that in normal therapeutic doses in healthy men, Proviron slightly suppresses the synthesis of gonadotropins in the pituitary gland and therefore does not reduce spermatogenesis. Unlike other androgens that replace endogenous androgens and inhibit their synthesis, Proviron integrates the action of endogenous androgens.

Additionally, unlike other orally active androgens, Proviron is well tolerated by the liver (probably due to a lack of core substitution for 17-alkyl steroids).

Proviron - description of the drug


Nevertheless, the level of the active substance in the blood serum decreases with a terminal elimination half-life of 12-13 hours. 98% of mesterolone binds to plasma proteins, 40% of mesterolone binds to albumin and 58% to sex hormone-binding globulin (SHBG).

The bioavailability of mesterolone is approximately 3% of the orally administered dose.

Proviron compensates for the lack of androgens, whose production gradually decreases with age. Therefore, Proviron provides treatment for conditions caused by a lack or complete absence of androgen production in the body. It does not reduce spermatogenesis in the recommended doses. The drug has no hepatotoxicity. Following oral administration, mesterolone is rapidly and almost completely absorbed in the dose range of 25-100 mg. The maximum serum concentration is 3.1 ± 1.1 ng / ml, reaching 1.6 ± 0.6 hours after taking Proviron. In doing so, the level of active substance in the serum decreases with a terminal half-life of 12-13 hours.98% of mesterolone binds to plasma proteins, 40% of mesterolone binds to albumin and 58% to albumin. (SHBG). Mesterolone is rapidly metabolized.

The rate of metabolic clearance from serum is 4.4 ± 1.6 ml / min – 1 / kg – 1. It is excreted by the kidneys only in the form of metabolites. The major metabolite is 1α-methyl-androsterone, in conjugated form, which accounts for 55 to 70% of metabolites excreted by the kidneys. The ratio of major metabolites of glucuronide to sulfate is approximately 12.1. The second metabolite is 1α-methyl-5α-androstane-3α, 17β-diol, which accounts for about 3% of metabolites excreted by the kidneys. No metabolic conversion to estrogen or corticosteroids has been reported. About 80% of the dose of mesterolone is excreted as metabolites in the urine, and about 13% of the dose is excreted in the faeces. Within 7 days, 93% of the dose returned to excretion, half of which was excreted in the urine within 24 years. The absolute bioavailability of mesterolone is approximately 3% of the oral dose. Oral administration of the daily dose of Proviron leads to an increase of about 30% in the level of the substance in the blood serum.

See info about Proviron during bodybuilding cycles


Androgen deficiency or male infertility caused by primary or secondary decreased gonadal function (hypogonadism) in men.


Prostate cancer (because androgens can trigger the growth of existing cancer).

Past or present liver tumors.

Hypersensitivity to the active substance or to any of the excipients.




Androgens should not be used in healthy people to build muscle or increase general physical fitness. To rule out prostate cancer during treatment, periodic prostate examinations are recommended.

Following administration of hormonal substances similar to those of Proviron, benign and even less common malignant liver tumors have been reported rarely. In some cases, bleeding into the abdominal cavity caused by these tumors was life-threatening. In case of severe pain in the epigastric region, enlargement of the liver or signs of intra-abdominal bleeding, the differential diagnosis should take into account the possibility of liver cancer.

Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Proviron - description of the drug

Special instructions

Healthy people should not take androgens to build muscle or increase the overall physical functional ability of the body.

As a preventative measure, periodic prostate examinations are recommended.
If frequent or very prolonged erections occur in some cases, the dose should be reduced or treatment discontinued to avoid complications after prolonged erections.

In rare cases, benign and even less often malignant liver tumors have been observed in the background of the use of substances with hormonal activity, including those that are part of the Proviron preparation, which in some cases can lead to life. threatening intra-abdominal bleeding. In cases of severe abdominal pain, liver enlargement or signs of intra-abdominal bleeding, the possibility of liver cancer should be considered in the differential diagnosis.

Characteristics of the effect of the drug on the ability to drive vehicles and potentially dangerous mechanisms.

The use of the drug does not affect the ability to drive potentially dangerous vehicles and mechanisms.


Proviron can be classified as a non-toxic drug. There is no risk of toxicity if one accidentally takes the drug at a dose several times higher than recommended for treatment.

Release and packaging form

  • 10 tablets in a blister consisting of a film of polyvinyl chloride and colored aluminum foil.
  • 2 ampoules, together with instructions for medical use in the official and Russian languages, are placed in a cardboard box.