, sure you can, and i will reiterate just for the record, I dont think 6 week cycles are 'extreme' at all, I think the 3 weekers are too short, but these are my opinions. Please remember I came up in the old days when people would run real anadrol and dbol for 2-3 months without thinking twice, and nolvadex was something still finding a place, and no one ever heard of pct, and pyramid cycles were all the rage.
I personally cant take the lethargy from sd, but the sides, if you do everything else perfect, are more than managable, and in my opinion, safe for 4-6 week cycles.
Let me also add this caveat:
If you cant not drink alchohol for a month, dont do sd.
If you cant afford a few hundred dollars of ancillaries and support supplements and pct, dont do sd.
If your diet and training isnt on point, do do sd.
If its your first 6 months of training, do do sd.