If damage has been done there's no guarantee that HCG will reverse it, although you're always better off with it to keep some production of intra-testicular testosterone . Also, just because they've atrophied doesn't mean they won't still somewhat function. You have to try. I'd consider upping your dose on your twice weekly protocol for now and see how it goes. Read the below excerpt from a current study. I can post the whole thing if you like but it's more geared toward fertility:
Human chorionic gonadotropin therapy
A known critical element in the development of healthy spermatogenesis is high intratesticular testosterone.13 In men using exogenous testosterone, these levels can be greatly diminished. Intramuscular human chorionic gonadotropin (hCG) therapy is an option shown to protect against, or at least to diminish, the impact that exogenous testosterone has on intratesticular testosterone levels . In a randomized, controlled trial of 29 healthy men randomly assigned to four groups, testosterone enanthate was given 200 mg per week plus either intramuscular saline, 125, 250, or 500 IU hCG every other day. Sperm, intratesticular testosterone levels, and gonadotropins were measured at day 0 and day 21. Intratesticular testosterone levels were suppressed by 94% in the placebo group, 25% in the 125 IU hCG treatment group, and 7% in the 250 IU hCG treatment group, and they were increased 26% from baseline in the 500 IU hCG treatment group.13 Thus, even with supraphysiologic doses of testosterone replacement, healthy levels of intratesticular testosterone were maintained by low-dose hCG therapy.
The benefits of hCG therapy are not limited to maintaining healthy levels of intratesticular testosterone levels alone. These benefits also include maintenance of spermatogenesis in males receiving testosterone supplementation. We have previously demonstrated the ability of hCG therapy to maintain spermatogenesis in men receiving TST. When 26 hypogonadal men receiving TST via transdermal patches or intramuscular injections and concomitant low-dose hCG were studied retrospectively, factors such as serum and free testosterone, estradiol, serum parameters, and pregnancy rates were evaluated. Results showed no differences in semen parameters during 1 year of follow-up, and none of the men became azoospermic during the treatment.14
These studies indicate that low-dose hCG may be beneficial for men requiring testosterone supplementation therapy during their reproductive years and that intramuscular or transdermal TST does not necessarily significantly impact spermatogenesis. Further studies are needed to determine whether this benefit is sustained both qualitatively and quantitatively.