The real answer is NO but its really not that simple.
This is your basic Google search answer that you get when researching proviron.
Proviron is the brand name for the orally applicable androgen and DHT(dihydrotestosterone)derivative called Mesterolone. Roughly 5% of testosterone undergoes 5-alpha reduction to form the potent androgen DHT, which is a sex hormone and androgen hormone. DHT plays a major role in the formation of the male genitals, and, in adults, it acts as the primary androgen in the prostate and hair follicles. Proviron is almost as pure a DHT steroid as you will find out there. With DHT compounds such as proviron, you need not worry about any estrogen aromatization.
Its confusing a bit because it says that you don’t need to worry about estrogen aromatization but it really means that you don’t need to worry about proviron becoming estrogen in the body.
Proviron is mesterolone
Which is DHT or (dihydrotestosterone) its a great addition to a cycle because of a couple different reasons. The rumor or the broscience that proviron will block your estrogen and can be used as an AI comes from that on a functional basis, Proviron carries four primary traits that largely define its mode of action. First and foremost the Mesterolone hormone has a strong binding affinity to Sex-Hormone-Binding-Globulin (SHBG). In fact, it appears to be one of the strongest anabolic steroids in this regard. By binding to SHBG, a hormone partially responsible for reducing free testosterone, binding SHBG will enhance the amount of circulating free testosterone. More importantly for the anabolic steroid user, it will make a larger percentage of the anabolic steroids used available in a free rather than bound state. A simple way to look at it is the anabolic steroids you’re taking become more powerful and potent.
Proviron also has the ability to interact with the aromatase enzyme, the enzyme responsible for the conversion of testosterone to estrogen. By binding to the aromatase enzyme, Proviron can actually inhibit aromatase activity, thereby offering protection against estrogenic side effects. It will not carry an anti-estrogenic effect near the level of power of an Aromatase Inhibitor (AI) but it will be notable. Depending on the nature of the cycle the individual undertakes proviron will help with estrogen but only with a low dosage of testosterone and this is only when the user is not estrogen sensitive.
I personally don’t run a cycle without proviron and I will run it with a trt or cruise dose as long as im on because of it making the testosterone more available and offering the higher free testosterone levels which is important to building lean mass.
So to anyone thinking about using proviron as an aromatase inhibitor please have a actually aromatase inhibitor like arimidex, aromasin, or letrozole on hand just in case its better to have then to get caught without one and end up needing surgery to remove the gyno that has set in go off of real research and take broscience with caution.