In simple terms, the brain does not care which hormone it has, just as long as it has enough. If there are consistently enough hormones in your body, it stops producing more. The “consistent” part is what injections are capable of that other administration routes struggle with. Trying to do sufficient monotherapy on pills, for instance, is very likely impossible in most situations. In more specific terms regarding the HPG axis, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are suppressed by increased serum estradiol (E2) levels, thus inhibiting GnRH production and by extension testosterone production in the testes.
+In simple terms, the brain does not care which hormone it has, just as long as it has enough. If there are consistently enough hormones in your body, it stops producing more. The “consistent” part is what injections are capable of that other administration routes struggle with. Trying to do sufficient monotherapy on pills, for instance, is very likely impossible in most situations. In more specific terms regarding the HPG axis, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are suppressed by increased serum estradiol (E2) levels, thus inhibiting testosterone production in the testes.