This is the expected result for LH and FSH when you're on a nontrivial dose of testosterone. Even hCG monotherapy can suppress these hormones. In short, don't expect to regain HPTA function unless treatment is limited to SERMs and/or AIs. Nonetheless, many guys regain fertility without restoring HPTA function. HCG is taking the place of LH anyway. HMG would provide some FSH. Dr. Saya's fertility rankings are below. I'd guess that TRT+hCG+hMG is close to 3(A).
A *very* generalized ranking of relative fertilities (with top being most fertile):
1. Clomid/SERM treatment
2(A). HCG + HMG (or lyophilized FSH)
2(B). Baseline no treatment (no HPTA suppression via TRT, AAS, HCG mono, etc) - assuming no significant degree of primary/secondary/tertiary dysfunction.
3(A). HCG monotherapy (does in fact result in HPTA suppression, especially at higher doses, but *may* move up to #2 in select cases of SECONDARY/TERTIARY hypogonadism)
3(B). TRT + HCG (as we know many men are still able to maintain adequate fertility to conceive)
4. TRT/AAS with no concurrent HCG.
HCG Monotherapy to Clomid Ratio For Fertility
www.peaktestosterone.com