Evidence-graded circadian products: sunrise alarms, SAD lamps, blue-light blockers, red light, blackout curtains and sleep masks. Sunlight first, studies cited.https://circadian.supply/https://circadian.supply/guides/best-light-color-for-sleep/https://circadian.supply/guides/best-light-color-for-sleep/The best light color for sleep is dim red or amber. Your body clock is most sensitive to blue light near 480 nm, and brightness matters as much as color.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/caffeine-half-life/https://circadian.supply/guides/caffeine-half-life/Caffeine half-life is 3 to 6 hours for most adults but can top 10 hours. What slows it, mg per drink, and when to stop caffeine before bed.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/circadian-apps/https://circadian.supply/guides/circadian-apps/A blue light filter app should turn your screen fully red and dim it, not just warm it. Two circadian apps worth installing: Tap Zap and Circadian.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/do-blackout-curtains-help-you-sleep/https://circadian.supply/guides/do-blackout-curtains-help-you-sleep/Blackout curtains for better sleep: what light at night does to sleep and blood sugar, how dark is dark enough (under 1 lux), and cheap fixes for light gaps.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/do-blue-light-glasses-work/https://circadian.supply/guides/do-blue-light-glasses-work/Do blue light glasses work? Not for eye strain, a 17-trial Cochrane review found. Dark amber lenses worn before bed have small, mixed sleep benefits.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/do-sunrise-alarm-clocks-work/https://circadian.supply/guides/do-sunrise-alarm-clocks-work/Do sunrise alarm clocks work? Dawn simulator trials show less morning grogginess and help for winter depression, but they don't replace a 10,000 lux light box.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/does-red-light-therapy-work/https://circadian.supply/guides/does-red-light-therapy-work/Does red light therapy work? Graded evidence for skin, hair loss, pain, muscle recovery, sleep and fat loss, with trial sizes, doses and FDA status.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/fda-cleared-red-light-therapy-devices/https://circadian.supply/guides/fda-cleared-red-light-therapy-devices/FDA cleared red light therapy devices explained: cleared vs approved vs registered, how to search the 510(k) database, and verified K-numbers for popular masks.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/how-many-lux-do-you-need/https://circadian.supply/guides/how-many-lux-do-you-need/Lux levels for sunlight, offices and homes, plus expert targets: 250 melanopic lux by day, 10 in the evening, 1 at night. How to measure your own.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/how-to-fix-your-sleep-schedule/https://circadian.supply/guides/how-to-fix-your-sleep-schedule/How to fix your sleep schedule: anchor one wake time, move it 15 to 30 minutes a day with morning light, and skip weekend sleep-ins. Includes a 7-day plan.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/how-to-reset-circadian-rhythm/https://circadian.supply/guides/how-to-reset-circadian-rhythm/How to reset your circadian rhythm: fix your wake time, get morning light, dim evenings. Expect about 1 hour of shift a day, and know when to see a doctor.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/how-to-use-a-sad-lamp/https://circadian.supply/guides/how-to-use-a-sad-lamp/How to use a light therapy lamp for seasonal affective disorder: 10,000 lux for 30 minutes, early morning, angled down. Side effects and who should skip it.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/jet-lag/https://circadian.supply/guides/jet-lag/How to get over jet lag: when to seek and avoid bright light after flying east or west, how to shift before you fly, and what melatonin trials show.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/morning-sunlight/https://circadian.supply/guides/morning-sunlight/Morning sunlight moves your body clock earlier. How many lux you get outdoors vs indoors, how long to stay out, and what to do on dark winter mornings.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/red-light-therapy-for-sleep/https://circadian.supply/guides/red-light-therapy-for-sleep/Red light therapy for sleep rests on one 20-person red light trial. Swapping white evening light for dim red or amber has better support. How to set it up.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/red-light-therapy-risks/https://circadian.supply/guides/red-light-therapy-risks/Risks of red light therapy, from eye damage and skin burns to photosensitizing drugs and overdosing, with who should skip it and how to use a panel safely.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/shift-work-sleep/https://circadian.supply/guides/shift-work-sleep/Shift work sleep tips from the research: bright light early in the night shift, dark glasses home, a blackout bedroom, anchor sleep, naps and caffeine timing.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/time-restricted-eating-circadian-rhythm/https://circadian.supply/guides/time-restricted-eating-circadian-rhythm/Time-restricted eating, graded against the trials: early windows helped insulin, but TRE has not beaten plain calorie cutting for weight loss.Tue, 20 Oct 2026 00:00:00 GMThttps://circadian.supply/guides/what-is-a-chronotype/https://circadian.supply/guides/what-is-a-chronotype/A chronotype is your body clock's timing, measured as free-day mid-sleep. How a real chronotype test works, what genes and age do, and why animal types fail.Tue, 20 Oct 2026 00:00:00 GMT