The HCG is for something completely different in terms of what the formeron is used for. I use hcg while on for faster recovery. Some people run hcg just before they finish their cycle. The only thing with that is the concerns i read about de-sensitizing the leydig cells with the over abundance of hcg when you blast at high doses.
To answer your question in short, no it's not neccesary but it sure is helpful when run properly. Good luck buddy
bro your balls are the most important aspect of recovery. so why don't feller's use HCG Is beyond me. Faster recovery = more gain's. Your nuts will be shutdown longer if you don't use HCG. The longer your shutdown the size you gained whiddles away.