then there are reports of some guys cruising on hcg mono on doses such as 250iu 3xweek, 500iu 2xweek. There are no studies validating the claim that hcg mono works only with higher doses, supraphysiological ITT was always required for fertility when rFSH was not used. Would be nice to have a study comparing 250, 500, 1000, 1500 eod effect on testosterone levels and e2, progesterone etc...
It's funny how the shot day of hcg there is always more libido, even though the effect on testosterone follows behind.
Here is where the other questions play a role. Age, how long you have been on Trt, which involve the capacity of your testicles to respond, etc.
It makes sense to start low, ex. 500 iu, wait and check labs, adjust dose, add complementary (Ex Ai, cabergoline), check again and so.
Through the last 4 years I have tried many different doses and combinations along my journey to fertility. I am 56 y/o, married to 24 years younger woman.
My experience: on Hcg mono: 500 IU EOD: total testosterone 560 ng/dl, E2: 38 pg/ml. Low libido
Then, HCG mono 1000 IU EOD: TT 420 ng/dl, E2 58 pg/ml, feeling hypogonadal.
So there is down-regulation or desensitization, may be for excess of intratesticular E2, or directly for less expression of LH receptors due to continues and higher exposure to Hcg stimulus.
Come back to HCG 500 IU eod, add testosterone 100 mg/week, feel good but need pde5i.
Add rFSH 75 IU to help semen parameters which still were not good, then got minimum good sperm count, motility, morphology. (Wife got pregnant once, miscarriage, then FIV twice: miscarriages, turned out she has got her own problems with uterine fibroids and inmune conditions, we still struggling for a baby)
Over time, I loose completely my libido and sperm quality go down, add Anastrozol and recover libido and can skip pde5i for first time in years, then sperm quality not good yet, stop trt (This is currently), and stay HCG monotherapy (780 IU ovitrelle every 3rd day) + rFSH + Anastrozol, results: testicles bigger and hanging more than I can recall, Libido getting better progressively after a dramatic fall. Need for pde5i. Sperm quality and labs to be tested yet.
Conclusions:
1- You need to do serial labs to know what HCG dose, frequency and combination with T. is good for you
2- There is for sure transitory down-regulation/ desensitization as you increase dose and frequency of HCG. E2 control is key.
3.- for fertility you can be on TRT (with hcg, fsh) but you are better off. Especially if you have some age and have been on trt for long time. Exogenous testosterone makes its own impairment at testicular level.