Cant say i've tried this either!
I have tried the salmon oil & the Yumega ... my honest opinion on both is that they didnt make any difference to my lot. They blew their coats as normal, grew back the same ... no changes
I find that feeding a good quality food, with raw meats, offal, bones etc works alot better for our dogs, their coats are always vibrant, dense & shiny when in full coat, and the usual patchwork when they are dropping LOL!!