Schering created Proviron in 1934, it is one of the oldest AAS. Schering also claims that mesterolone was the first product for treating men with low testosterone level. Mesterolone appeared around the same time with methyltestosterone (1935) and testosterone propionate (1937) and this drugs are considered as obsolete by modern standards.

Despite its age, Proviron has a long history of clinical application and is still used in medicine. It is prescribed for men in order to treat reducing of the physical and mental abilities caused by age, declining level of androgens, for treating  low libido, hypogonadism, infertility. Infertility treatment - is one of the most controversial points of this drug.

Chemical structure

Proviron (mesterolone) is an anabolic steroid derivative of dihydrotestosterone has a strong androgenic component and weak anabolic properties. Because of the high degree of SHBG function (globulin which is binding sex hormones), mesterolone improves the performance of other steroids in the body due to the increase of free testosterone in the blood of a man.

Mesterolone acts in the body as an aromatase inhibitor, slowing the conversion of steroids into estrogen, completely blocking the estrogen receptors.


  • Period of substance activity: 1-3 days
  • Classification: The steroid of anabolic / androgenic origin
  • Method of application: injection
  • Dosage: from 50 to 100 mg per day (every third day) for men / is not recommended for women
  • Acne: Yes
  • Water Retention: No
  • High blood pressure: Yes
  • Hepatotoxicity: no
  • Aromatase: No
  • Progestogenic activity: Yes
  • DHT (dihydrotestosterone) conversion: yes
  • Decrease of the HPTA function (testosterone production): Yes
  • Anabolic activity (400%) \ androgenic activity (200%)
  • Detection time - 6-7 weeks


  • Men's libido increase (sexual desire), improving potency.
  • Increase of muscle hardness and relief. This property leads to the frequent usage of Proviron in bodybuilding. It is used even by women, although in much smaller doses (however, these professional bodybuilders among women do not take notice of such ‘foolishness’).
  • Improving the quantity and quality of spermatozoids
  • Compensation of weak production of androgens.
  • Stimulation of the development of secondary sexual characteristics and male genitals.
  • Anabolic properties.

Side effects

Proviron can cause such side effects as baldness and prostate hypertrophy caused by the chemical nature of the active substance and its similarity to dihydrotestosterone. During the course of steroids it is recommended to carry out periodic examinations of the prostate.

There may be, though extremely rare, benign and malignant tumors of the liver. Also, when exceeding the recommended dosages and regimens such negative reactions as abdominal bleeding, enlarged liver and pain in the upper abdomen are not excluded. There are some erroneous information that Proviron reduces the effect of anabolic steroids, as acting on the same receptors. Contradiction to this statement is obvious: firstly, the high affinity of the drug with the binding protein increases the concentration of free AC, and secondly, the anti-estrogen is quickly destroyed in the muscle to inactive metabolites.

Dosages and Uses

Dosage: 50-150 mg

Frequency of doses: every day

Proviron course is not used on its own. Normally, the steroid is used in combined courses with other AAS as an anti-estrogen. The choice in such situations is usually between Tamoxifen and Proviron. The first drug, though, blocks the activity of estrogen receptors, does not interfere with their production.

Taking into consideration the ability of Tamoxifen to stimulate testosterone production, it is able to influence the pituitary gland, as well as reduce the anabolic activity of AAS which are used in parallel. That is why it is taken only during the PBC. On the contrary, Proviron is the prerogative during the course of steroids.

Cycles (Courses)

Proviron is usually taken from the second week of the course of steroids in a dose of 50 mg along with an aromatase inhibitor. But after 2-3 weeks after the course is finished Tamoxifen is added at a dose of 20 mg daily

Drug intake (for men)

The dosage is 50-150 mg / day. Maximum duration of the drug intake is up to 12 weeks. It is often used when low level of estrogen and high level of androgen is needed. For example, on cutting to increase fat burning.

Proviron 50-100 mg / day plus tamoxifen 10-30 mg / day is used to prevent estrogen side effects of steroids, as well as such phenomena as Deca-dik, tren-dik and so on (taking Proviron during the course along with trenbolone or nandrolone)

Drug intake (for women)

Mesterolone is not recommended for women due to high level of androgen in the drug. But it is believed that 25 / 50 mg / day + tamoksimen Proviron 10-20 mg / day can effectively burn women's fat.

But it is believed that 25 / 50 mg / day + tamoksimen Proviron 10-20 mg / day can effectively burn women's body fat.