Your body does when melatonin is taken in large amounts, which it usually comes in unfortunately. The original literature described a dose of something like 5 micrograms, and usually it comes in doses of several milligrams. So that’s why it will definitely make you sleep but you also feel so groggy the next day, the amount is far more than what occurs internally. I don’t disagree though to some extent. Many treatments seem to have reduction in effect over time, but still effective. Or needs to have changes in dosage/time off if possible. I think it would help if people better understood the sort of diminishing returns nature of it. Try to find a place where the effectiveness is good even if not great, and the dosage doesn’t cause issues. Such as with melatonin I didn’t really like to use it because the typical dose comes with the grogginess and all of that, but at the dose it should be at that didn’t happen.