Proviron is an androgen that competes for the oestrogen receptor, it does not aromatise and it resists the effects of other steroids when they aromatise. It becomes liver toxic but only in very large doses.
Mesterolone
Because it competes favourably for the testosterone receptor sites it can prevent other steroids from finding there receptors and doing a much better job at building muscle than Proviron can.
I personally think that nolvadex is a much better anti – oestrogen because of this.
Proviron Trade Names
Proviron, Mesterolone, Androviron, Mestoranum, Proviroxyl.