after an initial "... is that a misquote too? sounds super low" I decided to hunt around. I haven't seen anything on that low of a dose... but doing the math, it does seem to make some sense I suppose. a rough check of the total amount of melatonin in your blood at night implies something like 0.5mcg at peak (peak concentration at ~100pg/ml times 5L of blood). lots more is produced in a night because it has a short half-life, but yea, blood concentration is lower than I remembered.

what I also haven't seen though is anything covering how well it's absorbed through your digestive system. 0.3mcg intravenously I can certainly see being effective, but orally? sublingually? not sure. but you've definitely got me interested in looking more :)

(initial results: https://en.wikipedia.org/wiki/Melatonin_as_a_medication_and_... implies it varies quite a lot, but I'm seeing it centering around 15%-ish many places. so you might want like 3mcg to hit normal levels? and https://pmc.ncbi.nlm.nih.gov/articles/PMC5405617/ is implying 1-5mg -> 10x-100x normal concentration peak, so that does hit the right ballpark reasonably well... I guess I'm going to start experimenting with even smaller doses!)