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MESVIRON 25 is used to treat potency disturbances, infertility, declining physical & mental alertness in the aging male. It is an oral androgen which does not aromatize into estrogen. In clinical situations is generally used to treat various types of sexual dysfunction, which often result from a low endogenous testosterone level. It can usually reverse problems of sexual disinterest and impotency, and is sometimes used to increase the sperm count. The drug does not stimulate the body to produce testosterone, but is simply an oral androgen substitute that is used to compensate for a lack of the natural male androgen. It is also effective act as an anti-aromatase in the body, actually preventing or slowing the conversion of androgens into estrogens.

Thailand FDA approved registration # 1C 199/51  Approved October 10th 2008

MESVIRON 25 is approved for the following uses:

  • Declining physical activity and mental alertness in middle-aged and old men.
  • Hypogonadism , potency disturbances due to androgen deficiency
  • Infertility, Oligozoospermia, increased sperm count, improved quality and sperm motility.
Chemical: Mesterolone 25mg/tb
CAS Name: (1a,5a,17b)-17-Hydroxy-1-methylandrostan-3-one
Additional Names: 1a-methyl-5a-androstan-17b-ol-3-one; 1a-methyl-5a-dihydrotestosterone
Molecular Formula: C20H32O2
Molecular Weight: 304.47.
Percent Composition: C 78.90%, H 10.59%, O 10.51%
Melting point: mp 203.5-205.0°
Optical Rotation: [a]D20 +17.6° (c = 0.875 in CHCl3)

Prescription Medicine

Mesviron 25

Each uncoated tablet contains:
Mesterolone  25 mg


Mesviron 25 tablet contains 25mg of the androgen Mesterolone.


Mesterolone balances a deficiency of androgen formation, which begins to fall gradually with increasing age. Therefore, Mesterolone is suitable for treatment of all conditions caused by deficient endogenous androgen formation. In the recommended therapeutic dosage, Mesterolone will not impair spermatogenesis. Mesterolone is especially well tolerated by the liver.


  • Declining physical activity and mental alertness in middle and old aged men.
    Reduced efficiency, easy fatigability, lack of concentration, weak memory, disturbances of libido and potency, irritability, disturbances of sleep, depressive moods, and general vegetative complaints are often attributed to androgen-deficiency. These complaints can be overcome or improved by the use of Mesviron 25 tablets.
  • Potency disturbances
    Mesviron 25 overcomes potency disturbances due to androgen-­deficiency. It may also be of use as supplementary therapy in cases of diminished potency where androgen-deficiency is not the primary cause.
  • Hypogonadism
    Growth, development, and function of androgen-dependent target organs are stimulated by Mesviron 25. It promotes development of secondary male sex characteristics in cases of prepuberal hypogonadism. Full clinical and laboratory investigations are necessary in all cases of young patients prior to commencement of treatment. Mesviron 25 may also be used as a substitution therapy in cases where a loss of gonadal function has occurred postpuberally.
  • Infertility
    Oligozoospermia and deficient Leydig-cell secretion may be the cause of infertility. With Mesterolone treatment, sperm count can be increased, the quality improved and, furthermore, a higher fructose concentration up to normal values can be achieved thus increasing the chances of procreation.

In-patients with carcinoma of the prostate, androgen therapy of any kind, including the use of Mesviron 25 is contraindicated.


The administration of Mesviron 25 is recommended only for male patients.
Regular examinations of the prostate should be carried out prophylactically.


As directed by a physician. The following dosage may be recommended:

  • In declining physical activity and potency disturbances
    Commencement of treatment: One tablet of  Mesviron 25 three times daily.
    Continuation of treatment: One tablet of Mesviron 25 twice or once daily.
    According to type and severity of the complaints, a course of Mesviron 25 lasting four to six weeks or a prolonged uninterrupted treatment over several months is recommended. If required, the course of treatment may be repeated several times.
  • Hypogonadism requires continuous therapy
    For development of secondary male sex characteristics one tablet of Mesviron 25 3-4 times daily for several months. As maintenance dose, one tablet of Mesviron 25 twice or three times daily will be sufficient.
  • In Oligozoospermia
    One tablet of Mesviron 25 twice or three times daily for a cycle of spermatogenesis, i.e. 9O days.
    In case of simultaneously impaired gonadotrophic excretion, a combined therapy with gonadotrophic hormone exhibiting FSH activity is recommended for the commencement of treatment (e.g. 2000 IU serum gonadotrophin IM twice weekly up to a total amount of 12 000 IU). If necessary, treatment with Mesviron 25 is to be repeated after an interval of several weeks.


25 mg scored tablets in blister packs of 10 tablets  5 packs per box (50 tablets)

Formerly presented in bottles of 100 tablets of 25mg (bottles discontinued)

Store in a cool dry place. Protect from light.

Manufactured by: Unigen Life Sciences Co. Ltd.

Unigen Life Sciences Ltd. – WHO-GMP FDA Approved Steroid Hormone Manufacturer – Testosterone, Nandrolone, Stanozolol, Oxandrolone, Mesterolone, T3,T4