The Mesterolone hormone is not estrogenic. It does not aromatize and it carries no progestin nature. As a result, the side effects of Proviron will not include any related effects such as gynecomastia or excess water retention. Such adverse effects are impossible with this steroid. This will also greatly reduce the risk of high blood pressure as high blood pressure associated with anabolic steroid use is often due to extreme water retention. In fact, Proviron should provide an anti-estrogenic effect by preventing testosterone to estrogen conversion or at least tremendously slow it down.
There are studies of cell cultures, laboratory animals, wildlife, and accidentally exposed humans that show that environmental chemicals cause a wide range of reproductive, developmental, growth, and behavior effects, and so while "endocrine disruption in humans by pollutant chemicals remains largely undemonstrated, the underlying science is sound and the potential for such effects is real."  While compounds that produce estrogenic, androgenic, antiandrogenic, and antithyroid actions have been studied, less is known about interactions with other hormones.
In one small scale clinical trial of depressed patients, an improvement of symptoms which included anxiety, lack of drive and desire was observed.  In patients with dysthymia , unipolar , and bipolar depression significant improvement was observed.  In this series of studies, mesterolone lead to a significant decrease in luteinizing hormone and testosterone levels.  In another study, 100 mg mesterolone cipionate was administered twice monthly.  With regards to plasma testosterone levels, there was no difference between the treated versus untreated group, and baseline luteinizing hormone levels were minimally affected.