Mestanolone is the C-17 alpha alkylated version of DHT. This, of course, makes it orally bioavailable. It also adds some progestational activity to the molecule1. Methyl DHT cannot convert to estrogen, but it does bind strongly to SHBG which can displace estrogen into circulation possibly resulting in estrogenic side effects. As stated, DHT is deactivated in skeletal muscle by 3-alpha hydroxysteroid dehydrogenase as will Mestanolone2. However, if large enough doses are taken, it is possible that this enzyme may be overwhelmed and mestanolone would therefore bind to the AR resulting in quite strong anabolism but it has not been determined scientifically if this is possible and what dose would achieve this effect. Some people have an abnormal attraction to DHT and methyl DHT. They reason that since DHT is a stronger androgen that it must be a better anabolic and they refuse to acknowledge that these steroids are deactivated in skeletal muscle. The reason is probably due to the strong effect that DHT has on the psyche of the user. DHT will increase aggression and can cause significant strength gains though nervous stimulation.
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.
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.