That's two different questions, and the answers will depend on the individual, as is so often true in bodybuilding and in life in general.
In answer to your original question: to regain fertility while using HCG, is it necessary to go off test completely? Absolutely not, and the experiences of myself and thousands of other men who have fathered children while using test prove that it's not necessary. As
@gotgame and others have pointed out, as long as you are using HCG and HMG, you are bypassing any negative feedback to the pituitary from using exogenous test, so it should never be necessary to go off test completely, as long as you are using HCG and HMG or FSH.
But just because it wasn't necessary for me, doesn't mean it might not be necessary for you. I can't give you any definite guarantees for your own personal situation, as much as I wish that I could. Neither I nor anybody on the boards is your own personal endocrinologist, urologist, or fertility specialist, so take everything you read with a grain of salt. Although, I will say that there are a lot of guys on the boards who know more about this stuff than the vast majority of doctors. And we charge less. Hey, this is free advice, so take it for what it's worth LOL.
Might it be beneficial to go off test completely? Maybe, although it was never an option for me, as I have been on test for decades. But since you are already off test and producing sperm, you will have to weigh the pros and cons, and decide if that is the best option for you personally.
My own experience, as I have written in many other threads, is that I am 53 years old, and I have been on test and other steroids for over 29 years now. When my wife and I decided we wanted another child, I had complete azoospermia (zero sperm count), and my wife had her own fertility issues as a mother in her forties.
I kept using test at 200-300mg per week, never went off, and started using HCG, Proviron, and Clomid, which over the course of 7 months only brought me up to a 7 million sperm count with poor motility and morphology. I then added HMG, which over the next 4 months brought me up to 31 million sperm count with vastly improved motility, morphology, and forward motion, and my wife was pregnant.
I never went off test at any time during my fertility protocol.
If I could do it all over again, I would have used HMG from the beginning, but I didn't have access to it at first, and let's be honest and say that HMG is an expensive drug if you are using sufficient quantities of it for fertility purposes.
My protocol changed as I went through the eleven months, but if I had to do it all over again, I would have used HMG from the beginning and kept it simple:
Test 200-300mg per week, or whatever TRT amount you feel comfortable and have good libido
HCG 500iu every other day
HMG 30-60iu every day (the FSH and LH in HMG have very short half-lives, and it is best used with small daily or even twice-daily injections.)
My baby daughter is almost 19 months old now, and she is the absolute light of my life and my pride and joy. She is in the 99th percentile of both height and weight, and she is more intelligent than I would have thought possible. Cognitively the pediatrician agrees with me that she is 6 months to a year ahead of where most children are at this point in their lives. She knows her alphabet and numbers, and can read words to me from her children's books. We go for walks to the playground every day, and she literally is reading off the license plates on cars to me as we walk by.
She's going to be a little world-shaker and heart-breaker, and she amazes me all the time. It has been the greatest blessing of my life to have her, and I thank God for her every day.
I hope that you and your woman are equally as blessed, and have your own child very soon. All it takes is time and money, a lot of HCG and HMG, and a lot of prayers and waiting. But when you finally get your own child, in all honesty that's the greatest thing in the world. I am grateful to have that opportunity. I hope you have that same opportunity yourselves.
Best wishes,
Sides