Circadian Light Protocol
Satchin Panda's circadian light protocol pairs bright light early in the day with dim, warm light at night to keep your body clock on schedule. Morning daylight suppresses lingering melatonin and sharpens alertness, while evening screens and bright bulbs suppress the melatonin you need for sleep, making this one of the cheapest, highest-yield circadian levers available.
Get bright daylight in the first half of the day 30 to 60 min of outdoor daylight, or sit by a large window; the earlier the better
Morning light anchors the clock, boosts daytime alertness and sets up melatonin at night.
Don't let daytime be dim Work near windows or under bright light during the day; dim indoor light is not enough of a 'day' signal
Dim daytime light fails to fully anchor the clock and can leave you sleepy.
Lower and warm your light a few hours before bed 2 to 3 hours before bed: dim lights, switch to warm/orange tones, reduce screens
Evening blue light suppresses the melatonin rise you need to fall asleep.
Keep the bedroom dark for sleep Block light while sleeping; minimise late-night bright screens and artificial night light
Panda's line: in modern life we have 'lost our right to darkness', and night light disrupts metabolism and sleep.
Get blue light by day without frying your eyes Seek daylight, but do not stare at the sun; brief, sensible outdoor exposure is the goal
You want enough daytime blue light to set the clock while still protecting your eyes.
Keep light and sleep timing regular Similar light exposure and sleep/wake times across days, including weekends where possible
Consistency keeps the clock stable; erratic light and timing desynchronise it.
Specialised melanopsin cells in the retina detect blue light and signal the master clock.
View sources
Why early bright light exposure is key for melatonin at night (Dr. Satchin Panda)
How evening light exposure affects mood and the circadian clock (Dr. Satchin Panda)
Satchin Panda on Circadian Light, Melatonin Biology & Peak Cognition (FoundMyFitness #065)
A circadian plan anyone can follow (Dr. Satchin Panda)
Not medical advice. This page is for education only and is not a substitute for professional medical care. Consult a qualified clinician before changing your health routine.
Independent curation. YourProtocol is an independent platform. This protocol is based on the publicly available work of Satchin Panda and is not created, reviewed, endorsed by, or affiliated with Satchin Panda or Salk Institute.
Is this for you
- Anyone who sleeps poorly or wakes groggy
- Indoor and desk-bound workers
- Shift workers and travelers
- People optimising energy and circadian health
Cautions
- Light is one lever; pair it with consistent sleep timing and sensible meal timing for full effect
- Bright-light exposure can affect people with bipolar disorder or some eye conditions; if that applies, check with a clinician before using bright lamps
- Never look directly at the sun to 'get light'; sensible outdoor exposure is enough
- Shift workers face a genuinely hard problem and may need a tailored plan
- Educational only, not medical advice
- Manta Sleep
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