Chemical name: 1α-Methyl-17β-hydroxy-[5α]-androstan-3-one
Formula: C20H3O2
Anabolic activity index: 150%
Androgenic activity index: 40%

Mesterolone, sold under the brand name Proviron, is a synthetic androgen and anabolic steroid (AAS). It is primarily used in medical settings for the treatment of male hypogonadism and to support fertility in cases of low sperm count. Here is a detailed description of Mesterolone:

1. Classification and Mechanism of Action:

• Mesterolone is classified as an androgen, a type of sex hormone that promotes the development and maintenance of male characteristics. It is an oral derivative of dihydrotestosterone (DHT).
• As an androgen, mesterolone interacts with androgen receptors in the body, influencing various physiological processes.

2. Medical Uses:

• Mesterolone is prescribed in the treatment of male hypogonadism, a condition characterized by insufficient testosterone production. It may help supplement low androgen levels.
• In some cases, it is used to support fertility in men with oligospermia (low sperm count) or other reproductive health issues.

3. Androgen Replacement Therapy:

• Mesterolone is employed as part of androgen replacement therapy to address androgen deficiencies and related symptoms.

4. Bodybuilding and Sports Enhancement:

• Outside of medical uses, mesterolone is sometimes used by bodybuilders and athletes for its androgenic effects. It is believed to enhance muscle hardness and definition, making it potentially useful in cutting cycles.

5. Estrogen Inhibition:

• Mesterolone has a weak inhibitory effect on aromatase, an enzyme responsible for converting androgens into estrogens. This characteristic may help reduce estrogen-related side effects.

6. Dosage and Administration:

• The dosage of mesterolone can vary based on the specific medical condition being treated or, in the case of non-medical use, individual goals and tolerance.
• It is typically administered orally in the form of tablets.

7. Side Effects:

• Common side effects of mesterolone may include acne, oily skin, and increased facial or body hair.
• While it has a lower risk of estrogenic side effects compared to some other anabolic steroids, androgenic side effects are possible.

8. Precautions and Contraindications:

• Mesterolone is contraindicated in individuals with known hypersensitivity to the drug or any of its components.
• It should be used with caution in individuals with pre-existing liver conditions.

9. Monitoring and Medical Supervision:

• Mesterolone use, especially in non-medical contexts like bodybuilding, should be done under the supervision of a qualified healthcare professional.
• Regular monitoring of liver function and hormonal levels may be necessary.

Mesterolone is a prescription medication, and its use should always be guided by a healthcare professional. Its non-medical use, such as for performance enhancement in sports or bodybuilding, is often subject to legal restrictions and regulations. Individuals should be aware of potential risks, side effects, and legal considerations before using mesterolone for non-medical purposes.