It probably is less suppressive than other AAS because it does not aromatize (estrogen suppression) and it binds weakly to the AR (androgen suppression)
It also lower SHBG.
But all androgens will cause suppression to varying degrees.
I ran winny for 10 weeks for my first cycle ever. Didnt know much about what i was doing and didnt do PCT. Lemme just go ahead and say yes, its suppressive. TRUST ME.