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!)

I'm not finding any 5mcg on amazon tbh. Likely in no small part because its search is trash nowadays. Mind sharing a link?