I was told this by a doctor and just couldn't believe it was true, turns out good habits like consistent wake time and winding down well before lying in bed are super important.
Same here. Only happens when I am literally exhausted from a week of 3 hour sleep. Don't even drink coffee. Been like this for as long as I can remember
I have no idea of the stats but I usually absent jet lag, otherwise being on a weird schedule, or having my mind spinning about something fall asleep quickly.
I do use melatonin but mostly only in conjunction with international travel.
Definitely makes sense that absorption is faster than simply taking orally.