I don't think they do per say but some of the better ones follow estrogen. hCG will drive up your estrogen. Pregnenolone, DHEA and DHEA-S can also be followed. hCG therapy puts these up as well. The tell tale sign for most patience is that the testes increase in size and any pain associated with testes atrophy goes away. I use it on and off. There are a few other ways to get the boys somewhat back in the game. You can look into these. I don't have pubmed references on hand but they are available. Pregnenolone can be supplemented. Using Nolvadex instead of n AI may help. AI's in general are rough on blood lipids tanking HDL and increasing LDL and triglycerides. Nolvadex does the opposite. It can increase HDL, decrease LDL and help normalize Triglycerides. Some docs will supplement DHEA and or DHEA-S. These act as intermediates in steroid synthesis so supplementing basically back-fills pathways.
The testes do not only make testosterone. They make pregnenolone, androstenolone, estrogens, progesterone, DHEA, DHEA-S and many others. Pregnenolone is the mother intermediate and goes on to make cortisol and other mineralocorticoids as well as other corticosteroids. So shutting down the testes can be a problem for some people. the adrenals, paraadrenals and other tisses can make up the difference but some people are more sensitive to the deficit.
So to use hCG or not is up to yo and your doctor. I don't see much of a downside of giving it a try. You can monitor estradiol, DHEA-S and pregnenolone and you and your doc can evaluate. Getwith a good doc and see what's up if you think it might help.