Here is Dr. Saya’s conclusion:
The clinical use of human chorionic gonadotropin (hCG) as an adjunctive treatment to testosterone replacement therapy (TRT) in males is an important, and often overlooked and misunderstood, aspect of successful treatment of hypogonadism. However, a consensus on use and dosing/frequency has not been reached among practitioners and the situation is complicated by the degree of bio-hormonal individuality present across the population and the varying effects and goals of hCG treatment in different clinical scenarios (low SHBG levels, high estradiol levels, fertility concerns, etc). The data in this limited case study suggest that a dosage of 150iu hCG appears to attain minimal to moderate stimulation (serum concentration of 1mIU/mL) of the testicular leydig cells for a duration less than 24 hours and would likely be insufficient to attain continuous stimulation of the testicular leydig cells, UNLESS given on a daily basis, perhaps more frequently. Whereas, an injection of hCG 500iu appears to attain moderate stimulation (serum concentration 2mIU/mL- > 3mIU/mL -> 3mIU/mL-> 1mIU/mL) for a period slightly longer than 3 days (72 hours), likely enabling twice weekly , evenly spread , injections to attain continuous stimulation. As noted previously, I believe these patterns also suggest that a dosage regimen of hCG 250iu-350iu on an every other day (QOD) schedule would likely offer an alternative regimen for moderate, relatively steady and consistent testicular stimulation, although more data would be needed to confirm this conclusion.