I use pharmaceutical bayer proviron.
It helps a bit to get rid of some water, but not comparable to masteron. Mesterolone is the steroid with the greatest affinity to SHBG (4.4 times of endogenous dht). It does NOT decrease SHBG, it binds them with great affinity, freeing up more testosterone and dht. Thr problem is that too much free test could increase aromatization to estradiol. Moreover, estradiol is also bound in minimal part to SHBG, so there are chances of increasing free e2 too. Mesterolone acts as a mild steroidal aromatase inhibitor (like exemestane, but the latter is much more stronger).
For me, the more proviron i take with test, the more i have to increase my AI dosage. Wellbeing, strenght, hardness and libido are due to higher free test and dht on proviron.
Mesterolone is also rapidly deactivated by the 3 alpha HSD enzyme into 5 alpha androstanediol, that's why proviron is not directly anabolic per se. 5 alpha androstanediol acts as a neurosteroids (GABA modulator) and it contributes to the weelbeing on proviron.
Generally speaking i feel good on proviron, but sometimes it makes me feel edgy, other times nervous and aggressive, other times emotional. I think it depends by the levels of e2 at the moment.