The absolute best way to recover fertility is to get off test. Clomid/HCG/HMG will all help to restart your HPTA and ease the transition from TRT to going back to natural. Lots of guys can stay on TRT and add HMG and achieve fertility/pregnancy. Thats not always the case. I was 8.5 years in on TRT when my wife and I decided to try for kids. From 36 to 44 I used 500-750 i.u s a week of HCG religiously. My sperm count was 0. So when I met with a urologist he said its very common to be infertile on TRT and the longer you're on/older you are the greater the suppression.
Was able to achieve solid fertility in 3 months off of the test. We are awaiting a IVF transfer due to her issues but my sperm is now good to go. I have also done cryogenic savings of 3 vials in case we need more for the future.
I'll start back on TRT in the next week or so and I'm thrilled! I used 50mg clomid ED+ 2500 i.u HCG 3x a week for recovery. After 4 months on the clomid o bailed on that and they gave me Natesto which is a gel you pump into each nostril 2-3 times a day. Will bump up your testosterone without shutting down your HPTA. Very nice for those wanting to have the benefit of test without having to completely come off while recovering. Hope some of this is helpful. If you have insurance than definitely explore working with a urologist as you'll get expertise and pharmaceutical grade recovery meds at a good deal. My HCG was 6 bottles of 5000Pregnyl + pins/sharps containers for 32.50 USD!