Many bodybuilders favor the use of mesterolone during dieting phases or contest preparation, when low estrogen and high androgen levels are particularly desirable. This is especially beneficial when anabolics like Winstrol®, Anavar, or Primobolan® are being used alone, as the androgenic content of these drugs is relatively low. Mesterolone can be effectively used here to adjust the androgen to estrogen ratio upwards, bringing about an increase in the hardness and density of the muscles, supporting libido and general sense of well being, and increasing the tendency to burn body fat. It is also commonly used (at a similar dosage) to prevent gynecomastia when other aromatizable steroids are being administered, often in conjunction with 10-20 mg per day of Nolvadex.
Proviron has four distinct uses in the world of bodybuilding. The first being the result of its structure. It is 5-alpha reduced and not capable of forming estrogen, yet it nonetheless has a much higher affinity for the aromatase enzyme (which converts testosterone to estrogen) than testosterone does. That means in administering it with testosterone or another aromatizable compound, it prevents estrogen build-up because it binds to the aromatase enzyme very strongly, thereby preventing these steroids from interacting with it and forming estrogen. So Mesterolone use has the extreme benefit of reducing estrogenic side-effects and water retention noted with other steroids, and as such still help to provide mostly lean gains. Its also been suggested that it may actually downgrade the actual estrogen receptor making it doubly effective at reducing circulating estrogen levels.
As this anabolic steroid is not very liver toxic, in-fact it is quite mild it can be used for extended periods of time; if you are not susceptible to DHT based side-effects you could reasonably supplement with Proviron the entire duration of your cycle. While it can be used for extended periods, as we will see dosing protocol can vary dramatically depending on the purpose for which it is used. If Proviron is being used simply as a quasi-anti-estrogen medication then a mere 25mg per day may be all you need but many will find 50mg to be needed if their cycle contains a high dosing of aromatizing steroids. For those who are supplementing for additional beneficial purposes higher doses may be needed; although 50mg will provide them solid effects a slightly higher bump may be needed. If you choose to use Proviron this is something you may need to play with as individual response will vary greatly. For the individual who supplements for the purpose of bridging, a rather common purpose of Proviron use, doses will necessarily be much higher, ranging from 100mg-150mg per day if the individual is going to obtain the desired effect and benefits.