Consumer medicine information




Brand name


Active ingredient





Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using PROVIRON.


This leaflet answers some common questions about Proviron.

It does not contain all of the available information.

It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking Proviron against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.


Proviron is used to replace testosterone in men with hypogonadism. Male hypogonadism is a condition when the body does not produce enough testosterone.

Testosterone is a natural male hormone, known as an androgen, which controls normal sexual development in men.

Testosterone is essential for the development and maintenance of the male reproductive organs as well as other male characteristics, such as hair growth, deep voice, sexual drive, muscle mass and body fat distribution.

Proviron is for use in male patients only.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.


When you must not take it

Do not take Proviron if you have an allergy to:

  • mesterolone, the active ingredient in Proviron
  • any of the ingredients listed at the end of this leaflet.

Some of the symptoms of an allergic reaction may include:

  • shortness of breath
  • wheezing or difficulty breathing
  • swelling of the face, lips, tongue or other parts of the body
  • rash, itching or hives on the skin.

Do not take Proviron if you have:

  • prostate cancer
  • previous or existing liver tumours
  • male breast cancer
  • high blood calcium levels

Do not use this medicine after the expiry date printed on the pack and blister. The expiry date is printed on the carton and on each blister after “EXP” (e.g. 11 18 refers to November 2018). The expiry date refers to the last day of that month. If it has expired return it to your pharmacist for disposal.

Do not use this medicine if the packaging is torn or shows signs of tampering. If the packaging is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Before starting Proviron, your doctor will conduct an examination of your prostate. Your doctor will also note your medical history and perform other tests including a blood test.

Tell your doctor if you have or have had any of the following medical conditions:

  • prostate disease
  • liver disease
  • heart or blood vessel disease
  • high blood pressure
  • kidney disease
  • difficulty passing urine
  • migraines
  • epilepsy
  • diabetes
  • sleep apnoea (abnormal pauses in breathing during sleep)
  • polycythaemia (a blood disorder where too many red blood cells are being produced)
  • porphyria a rare metabolising disorder

If you have not told your doctor about any of the above, tell him/her before you start taking Proviron.

Use of androgens for reasons other than what your doctor prescribed carries a serious health risk and is strongly discouraged.

Use of Proviron during puberty can stunt your growth. Your doctor can discuss with you the risks and benefits involved.

Taking other medicines

Tell your doctor if you are taking any other medicines, including those that you buy without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and Proviron may interfere with each other. These include:

  • phenobarbital or phenytoin, medicines used to treat seizures
  • cyclosporin, a medicine used to suppress the immune system
  • medicines used for diabetes
  • thyroxine, a medicine used to replace low thyroid levels
  • oral anticoagulants such as warfarin, ‘blood thinning’ medications to treat or prevent blood clots
  • neuromuscular blockers such as anaesthetics, medicines used to cause temporary paralysis

These medicines may be affected by Proviron or may affect how well it works. You may need different amounts of your medicines, or you may need to take different medicines.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.


Follow all directions given to you by your doctor or pharmacist carefully. They may differ from the information contained in this leaflet.

If you do not understand the instructions printed on the pharmacist label, ask your doctor or pharmacist for help.

How much to take

Your doctor or pharmacist will tell you how much and how often you should take Proviron.

For Proviron to work best it is very important to take it exactly as your doctor tells you.

The usual treatment consists of 1-2 tablets three times per day. After a few months of treatment, your doctor may decrease the dose to 1 tablet two to three times a day.

Do not exceed the recommended dose your doctor has prescribed for you as this can increase your risk of side effects.

How to take it

Swallow the tablet whole with water.

When to take it

Take your medicine at about the same time each day

Taking it at the same time each day will have the best effect. It will also help you remember when to take it. It does not matter if you take this medicine before or after food.

How long to take it

Continue taking your medicine for as long as your doctor tells you. This medicine helps control your condition, but does not cure it. It is important to keep taking your medicine even if you feel well.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking it as you would normally.

Do not take a double dose to make up for the dose that you missed.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering when to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor, or the Poisons Information Centre (telephone 13 11 26), or go to the Accident and Emergency department at your nearest hospital, if you think you or anyone else may have taken too much Proviron. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Excessive use of hormonal substances such as Proviron has been associated with liver abnormalities, tumours, changes to blood lipids, increased risk of heart disease, reduced glucose tolerance, decreased testosterone levels, enlargement of male breast tissue, stunted growth, psychiatric disturbances, acute withdrawal syndrome, vomiting blood or blood in stools and tendon damage.


Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking Proviron.

Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. It may affect other medicines used during surgery.

Keep all of your doctor’s appointments so that your progress can be checked. Your doctor may do some tests (such as blood tests and regular examinations of the prostate) from time to time to make sure the medicine is working and to check for unwanted side effects.

If you experience prolonged stomach pain, blood in the stools or vomit, or yellowing of the skins and eyes during treatment with Proviron, tell your doctor immediately There have been cases reported of patients developing liver tumours while taking Proviron. Your doctor may tell you to stop using Proviron.

Things you must not do

Do not take Proviron to treat any other complaints unless your doctor tells you to.

Do not give your Proviron tablets to anyone else, even if they have the same condition as you.

Do not stop taking your medicine or lower the dosage without checking with your doctor. If you stop taking it suddenly, your condition may worsen or you may have unwanted side effects.


Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Proviron. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

Do not be alarmed by the following lists of possible side effects. You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • headache
  • fluid retention
  • breast enlargement
  • increased sexual drive
  • psychiatric disturbances such as depression, aggression, increased or decreased energy levels, elation or irritability
  • acne
  • excessive hairiness
  • premature puberty
  • stunted growth

Tell your doctor immediately, or go to Accident and Emergency department at your nearest hospital if you notice any of the following:

  • symptoms of an enlarged prostate such as changes in urination, or blood in the urine or ejaculate
  • unwanted, frequent or prolonged and painful erections
  • severe stomach pain or tenderness which do not disappear within a short time

You may need urgent medical attention or hospitalisation.

Hormonal substances such as Proviron may quicken the growth of existing hormone dependent tissues and tumours If you are over 65 years of age, you may have an increased risk of developing prostatic hyperplasia (enlargement of the prostate) and prostatic cancer.

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.



Keep your tablets in the pack until it is time to take them. If you take the tablets out of pack, they may not keep well.

Keep your tablets in a cool dry place where the temperature stays below 30°C.

Do not store it or any other medicine in the bathroom, near a sink, or on a window-sill.

Do not leave it in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a half metres above the ground is a good place to store medicines.


If your doctor tells you to stop taking Proviron or the tablets have passed their expiry date, ask your pharmacist what to do with any that are left over.

Return any unused medicine to your pharmacist.


What it looks like

Proviron tablets are round white scored tablets marked with “AX” inside a hexagon.

Each pack contains 50 tablets.


Active ingredient:

  • 25 mg mesterolone per tablet

Inactive ingredients:

  • lactose
  • maize starch
  • povidone
  • methyl hydroxybenzoate
  • propyl hydroxybenzoate
  • magnesium stearate


Made in Germany for:
Bayer Australia Ltd
ABN 22 000 138 714
875 Pacific Highway
Pymble NSW 2073

Australian Registration Number
Proviron (blister pack) - AUST R 136196
Proviron (bottle) - AUST R 10712

Date of preparation

November 2012

See TGA website ( for latest Australian Consumer Medicine Information.

® Registered trademark of the Bayer Group, Germany

© Bayer Australia Ltd

All rights reserved

Published by MIMS March 2013


Brand name


Active ingredient





Name of the medicine



Lactose, maize starch, povidone, methyl hydroxybenzoate, propyl hydroxybenzoate and magnesium stearate.


Chemical name: 17 β-hydroxy-1 α-methyl-5 α-androstan-3-one. Molecular formula: C20H32O2. MW: 304.47. CAS: 001424-00-6. Melting point: 205 to 211°C.
Mesterolone is a white to yellowish crystalline powder and is practically insoluble in water. Proviron is a hormonal preparation.



Mesterolone (Proviron) has androgenic properties. Early studies suggested oral mesterolone did not usually suppress gonadotrophins or endogenous testosterone production. A later single dose study suggests there may be a central suppression effect at doses of 75 to 100 mg daily.


Following oral ingestion mesterolone is rapidly absorbed. In a study in 18 men the intake of Proviron 25 mg generated maximum serum drug levels of 3.1 ± 1.1 nanogram/mL after 1.6 ± 0.6 hours. Thereafter, drug levels in serum decrease with a terminal half-life of 12 to 13 hours. Mesterolone is bound to serum proteins by 98%. Binding to albumin accounts for 40% and binding to SHBG (sex hormone binding globulin) to 58%.
Mesterolone is rapidly metabolised. The metabolic clearance rate from serum accounts for 4.4 ± 1.6 Renal excretion of unchanged drug has not been detected. In a study of 14C labelled mesterolone in two men, up to 2% of mesterolone was excreted as the conjugated form in the urine. The main metabolite has been identified as 1α-methyl-androsterone, which, in conjugated form, accounts for 55 to 70% of renally excreted metabolites. The ratio of conjugated main metabolite glucuronide to sulfate detected in urine was about 12:1. As a further metabolite 1α-methyl -5α-androstane-3α, 17β-diol has been recognised, which accounted for about 3% of renally eliminated metabolites. Mesterolone was excreted in the form of metabolites. Within seven days approximately 80% of the labelled doses were recovered in the urine and up to 13% in the faeces. Half of the labelled doses were excreted in the urine within 24 hours.
The absolute bioavailability of mesterolone was determined to be about 3% of the oral dose.


Hypogonadism. Androgen replacement for male hypogonadism, where there is androgen deficiency confirmed by clinical and biochemical testing. (See Precautions and Dosage and Administration.)


Carcinoma of the prostate, previous or existing liver tumours, breast cancer, hypercalcaemia.
Hypersensitivity to the active substance or to any of the excipients.


Androgens are not suitable for enhancing muscular development in healthy individuals or for increasing physical ability (see Adverse Effects).
The diagnosis of hypogonadism in males requires full endocrinological assessment including clinical history and physical examination, expert interpretation of serial measurements of serum testosterone, luteinising hormone (LH) and follicle stimulating hormone (FSH), additional tests as required to identify underlying disorders and evaluation of the general health of the patient. See Dosage and Administration.
Prostate disease should be excluded prior to commencement and regular examinations of the prostate should be carried out prophylactically.
Hepatic impairment (monitoring of hepatic function is recommended).
Conditions aggravated by fluid overload from sodium or fluid retention, such as cardiovascular disorders or renal impairment, hypertension, epilepsy or migraine.
In older men, urinary obstruction may be precipitated. Increased libido may occur.
Use in puberty may cause premature closure of the epiphyses and stop linear growth.
Diabetes mellitus, androgen sensitive polycythaemia or sleep apnoea may be exacerbated.
Androgens are considered to be unsafe in patients with porphyria.
In rare cases benign and in even rarer cases malignant liver tumours leading in isolated cases to life threatening intra-abdominal haemorrhage have been observed after the use of hormonal substances such as the one contained in Proviron. Peliosis hepatis has been reported in patients who received high doses over a prolonged period. Upper abdominal complaints should be reported to the doctor.

Carcinogenicity, mutagenicity and impairment of fertility.

The carcinogenic potential of mesterolone has not been investigated in long-term studies. However, sex steroids are known to promote the growth of certain hormone dependent tissues and tumours. There are rare reports of hepatocellular carcinoma in patients receiving long-term therapy with androgens at high doses. Withdrawal of the drugs did not lead to regression of the tumour in all cases. Chronic androgen deficiency is a protective factor for prostatic disease and hypogonadal men receiving androgen replacement therapy require surveillance for prostate disease similar to that recommended for eugonadal men of comparable age. Geriatric patients treated with androgens may be at an increased risk for the development of prostatic hyperplasia and prostatic cancer.
The genotoxic potential of mesterolone has not been investigated.
The effects of mesterolone on fertility and early embryonic development have not been investigated. Proviron is for use in male patients only.
Mesterolone was shown to inhibit spermatogenesis in animals following oral administration. Fertility studies on the effect on sperm cells in humans have not been carried out with Proviron.

Use in pregnancy.

(Category X)
Proviron is for use in male patients only.


Drug interactions which result in an increased clearance of sex hormones can lead to decreased therapeutic efficacy. This has been established with many hepatic enzyme inducing drugs (including phenobarbital and phenytoin).
Androgens have been reported to enhance the activity of a number of drugs, with resulting increases in toxicity. Drugs affected include cyclosporin, antidiabetics, thyroxine and anticoagulants, such as warfarin. Resistance to the effects of neuromuscular blockers has also been reported.

Effects on laboratory tests.

Androgens may interfere with a number of clinical laboratory tests, e.g. those for glucose tolerance and thyroid function.

Adverse Effects

There is little information available on reported adverse events for Proviron.
If, in individual cases, frequent or persistent erections occur, the dose should be reduced or the treatment discontinued in order to avoid injury to the penis.
Headache has been reported.
The following adverse effects have been reported for androgens in general.
Fluid retention, impaired glucose tolerance, altered lipids and haematological parameters, abnormal liver function tests.
Gynaecomastia, prostate hyperplasia, virilisation, priapism, increased libido, hirsutism, acne, precocious sexual development.
Premature epiphyseal closure.
Neoplasms including liver and prostate (See Contraindications and Precautions).
Psychiatric disturbances including mania, hypomania, depression, aggression and emotional lability have been described.

Dosage and Administration

The tablets are to be swallowed whole with some liquid.
Unless otherwise prescribed by the doctor the following dosages are recommended.


Before commencing therapy the diagnosis of hypogonadism should be unequivocally established; see Precautions.
For development of secondary male sex characteristics: 1 to 2 Proviron tablets 3 times per day for several months.
As maintenance dose: 1 Proviron tablet two to three times per day will often be sufficient.


There have been no reports of ill effects from acute overdosage.
Excess use of androgens has been associated with adverse effects including liver abnormalities, neoplasms, atherogenic blood lipid profile, increased risk of cardiovascular disease, reduced glucose tolerance, hypogonadal states, gynaecomastia, virilisation, early closure of epiphyses, psychiatric disturbances, acute withdrawal syndrome, gastrointestinal bleeding and tendon damage.
Symptomatic treatment should be undertaken based on individual clinical assessment.


Tablets, 25 mg (white): 50's (glass bottle, AUST R 10712), (blister strips, AUST R 136196).


Store all medicines properly and keep them out of reach of children.
For storage conditions and expiry date see the pack.

Poison Schedule