the guide splitting latency from WASO is the right frame, and it’s the part most sleep threads collapse into one bucket. so on the staying-asleep side specifically, a dosing note from my own log. melatonin: most people dose 3-5mg and treat it like a sleeping pill. it’s not. half-life is short, an hour or two depending on whose number you trust, and that’s the issue. is that measured in your blood or extrapolated from a label, because the dose-response on melatonin is pretty flat past ~0.5mg anyway. for me it moved onset maybe 20-30 min and did nothing for the 3am wake. by week six it stopped touching even onset, receptor downregulation, so i pulled it. mag glycinate at ~300-400mg was more consistent for the middle-of-night piece. different mechanism, it’s not racing a 2-hour half-life to cover an 8-hour window. the 3am wake is its own signal, separate from onset. that’s usually cortisol/HPA, not a melatonin gap, and no amount of pre-bed dosing fixes a 4am cortisol bump. fwiw i log sleep score against supplement days in a tracker, the nightly check-in reminder is the only reason i actually rate the night instead of forgetting by morning. ymmv.