In people

The response is fast and measurable. LH climbs within about thirty minutes of a dose and roughly triples at the amount that works best, and pushing harder than that gives less rather than more, which is the receptor's own ceiling. Held on long enough, testosterone rises by about half. Men with low desire showed changed activity in the sexual and emotional processing networks of the brain along with the hormone change, so the effect is felt as well as measured. People do not report the things an injected hormone causes, because nothing is being replaced: the body is being asked to make its own, and the ceiling is its own capacity. The most instructive finding is what happens when the signal never stops. Five days of unbroken exposure and the system went quiet, while the same amount given eight hours on and sixteen off held the response for twelve days with the receptor still fully alive at the end. Most of the human work has been in research units with the hormone measured every ten minutes, which is how this level of detail exists at all.