I think selegiline is useful, but it's in no way a replacement for hCG. The best replacement is the LH that hCG itself attempts to replace. However, if you're on TRT then the current known solutions for getting appropriate amounts of LH involve multiple daily injections. Most would find this impractical. It works for me, but I don't know of anyone else who's had good enough results to stay with it. There are gonadorelin pump systems out there that are being used instead of TRT. These could be used with TRT in cases where endogenous testosterone production was insufficient. It's still a complicated solution.