Backfilling is overhyped, IMHO. DHEA more than Preg, can be not well tolerated in a lot of guys, aromatases easily, etc. But like all of this some love DHEA, some love Preg, and some like me avoid it entirely. There are no negatives to not supplementing...it's like one of these things that (IMHO) it's treating a number on a lab page vs is it really necessary to do it.