Sleep onset requires three simultaneous conditions: sufficient adenosine (sleep pressure), correct circadian timing, and absence of arousal signals. Most sleep onset problems are caused by one or more being unmet. This guide covers the neuroscience, the paradoxical intention technique, stimulus control, cognitive shuffle, physiological sigh, the Glycine + L-Theanine + Magnesium Glycinate supplement sequence, and what makes sleep onset worse — including clock-watching and lying awake in bed.