Light

Get bright light in your eyes within 30 minutes of waking. This is the single most impactful thing you can do for circadian rhythm, energy, and sleep quality. Sunlight is best. Circadian lighting is the backup.

The rule is embarrassingly simple: sunlight hits your eyes before your phone does. No exceptions, no 'just checking one thing.' This single boundary recalibrates your circadian rhythm more than any sleep supplement, blackout shade, or smart mattress combined. It's the cheapest, highest-leverage protocol on the list — and the one most people refuse to do.