dbol is repressive and LH/FSH--->zero, T-->zero and testes will shrink, fertility concerns...
FT-->zero. FT-->E2 stops. E2 gets very low. E2 is important for many reasons, males are only a small deviation from the female blueprint.
There still will be background levels of T and estrogen production in the adrenals, similar to a castrated male.
When you shutdown T completely, T mediated gene expression in cell nuclei will stop. Sometimes parts of gene expression get damaged beyond recovery. You body and brain was shaped in the womb by testosterone, it would be foolish to take risks shutting of the forces of T that have always been there.
All cycles need testosterone! 100mg/week testosterone ester would be a normal amount of T.
I have the unique point of view of a guy who deals with completely broken HPTAs in the T replacement forum.