HCG

HCG (human chorionic gonadotropin) mimics luteinizing hormone (LH), directly stimulating the testes to produce testosterone and support sperm production — its key advantage over direct testosterone replacement is that it doesn't shut down the body's own fertility signaling.

A review covering the 1977-2020 literature concludes HCG is "a prime candidate for patients suffering from secondary hypogonadism" specifically because it avoids the infertility risk that comes with standard testosterone therapy. Fink et al., Expert Rev Endocrinol Metab, 2021 Separately, a retrospective analysis of men on non-prescribed androgens found HCG treatment raised mean total sperm count from 18.0 million to 146.9 million, with the share of men reaching a normal total motile sperm count rising from 5% to 58%.

No specific dosing protocol was independently verified against a primary source with full detail in this pass — HCG dosing in clinical practice varies considerably by indication (fertility preservation during TRT vs. primary hypogonadism treatment), and pulling the exact protocol from a specific trial is a worthwhile follow-up.

Not detailed with specific figures in the review source available for this pass — a real gap worth filling with a follow-up look at the primary trials themselves (the systematic review referenced above analyzed 7 trials covering 926 men, which would be the place to pull specific adverse-event rates from).