CLOCK, BMAL1, PER, CRY · The Molecular Clock
The 24-hour feedback loop inside every cell. The 2017 Nobel Prize in Medicine.
The Circadian Rhythm Library
Circadian Health
How light, timing and sleep govern the body clock, and what actually shifts it.
25 topics, ordered below with the best evidenced first.
What the evidence looks like across all 25 topics
Most of this library rests on human evidence.
| Grade | topics |
|---|---|
| 5Settled | 6 |
| 4Strong | 11 |
| 3Mixed | 6 |
| 2Thin | 2 |
| 1Untested | 0 |
17 topics rest on strong human evidence. 2 rest on little or none. How we grade evidence.
View
Browse by category
The Primary Zeitgeber
The single most powerful, most actionable circadian intervention. Get morning light.
Tissue Clocks · Every Cell Keeps Time
Your liver, muscle, and gut each run their own clock, and they can disagree.
Chronic Circadian Disruption
Classified a probable carcinogen. The most serious, most overlooked circadian harm.
Sleep Stages & The 90-Minute Cycle
Deep sleep in the first half, REM in the second. Cutting sleep short cuts REM most.
Suprachiasmatic Nucleus · The Master Clock
Twenty thousand neurons above the optic chiasm that run the entire body's clock.
Adenosine · Sleep Pressure / Process S
The molecule that tracks how long you have been awake, and the one caffeine blocks to hide the bill.
When You Eat vs What You Eat
The same meal eaten at night is metabolically worse than eaten in the morning.
Larks, Owls & Everything Between
Half genetic, age-shifting, and largely not your fault. Teens really are wired to sleep late.
PER3, CLOCK, CRY1 · The Genetics of Timing
A few rare variants flip your whole schedule. Most chronotype is hundreds of small ones.
CAR · The Morning Activation Surge
A programmed 50-100% cortisol surge after waking. Not stress, your clock turning the day on.
Acute Circadian Desynchrony
Eastward is harder than westward. The clock re-syncs about one hour per day.
Food as a Peripheral-Clock Zeitgeber
Food is the master zeitgeber for your organs, strong enough to override light.
The Hormone of Darkness
Not a sleeping pill, a darkness signal. And most people take 10x too much.
The Evidence-Based Morning Routine
Consistent wake time, morning light, then everything else. The highest-yield routine there is.
Seasonal Affective Disorder (SAD) · Circadian Mood Disruption
Recurrent winter-pattern depression tied to a delayed circadian clock, not the same thing as the winter blues.
Body Temperature Rhythm as a Zeitgeber
You fall asleep as your core cools. Warm your feet, cool your core, sleep faster.
Evening Light Exposure & Devices
The wavelength gets the blame, but brightness, and what you do on the screen, matter more.
Timing Medications to the Body Clock
When you take a drug can change how well it works, and how toxic it is.
eTRE · Circadian-Aligned Eating Window
The most metabolically powerful eating pattern, and the hardest to fit a social life around.
Movement as a Circadian Zeitgeber
Morning exercise shifts you earlier; evening shifts you later. Performance peaks late afternoon.
Weekday-Weekend Clock Mismatch
Living on two time zones at once, your body's and your alarm's. Most people have it.
Schedules, Meals & Social Rhythm
Regular social rhythms anchor the clock, and stabilizing them treats mood disorders.
Magnesium, Glycine, Theanine, Apigenin & More
Magnesium, glycine, and theanine have real (modest) data. Most sleep stacks oversell.
Sleep Trackers & Wearables · Measurement
These devices measure movement, heart rate, HRV and temperature. They infer sleep stages.
No topics match that combination. Choose another category, or show all 25.