This is one of those things you will get varying opinions on. I will give you my experience.
I have read a great deal about "backfilling the pathways" as well and tried HCG hoping it would do just that. After months of being on HCG and several tests, I saw no movement in my DHEA, Pregnenolone, or Progesterone serum results. My DHEA registered 64 (very low) and my Pregnenolone and Progesterone were so low they were undetectable.
I started supplementing with DHEA and Pregnenolone and finally saw some movement in backfilling. My DHEA is now at the top of the range, my Progesterone is now mid range, and my Pregenelone is moving upward and at 41, it still is on the low end, but moving up.
Some state they can not take DHEA or Pregnenolone but I think they have made me calmer and make me sleep better.
I have since stopped taking the HCG but continue the supplementation of DHEA and Pregnenolone.