You could use it for either that's the beauty about this product.as a recomp compound its unbelievable as your bf is very low to start with and the added TREST just fills you out in all the right places.
As for using it pre comp you have to be very attuned with your body as due to the high estrogen conversion you could 'overspill!'.
One person to use it for such purposes was schmo buster who had amazing results if i remember correctly!!