Your blue light filter isn't doing enough.
Circadian Shield uses CIE S 026 science to actually protect your circadian rhythm. 11 modes. Health dashboard. Light debt tracking. See the difference real science makes.
Blue light at night disrupts your sleep
Your display emits peak blue light at 450 nm — the exact wavelength that suppresses melatonin and confuses your body clock.
Delayed Sleep Onset
Evening blue light shifts your melatonin release by 1.5–3 hours, making it harder to fall asleep even when you feel tired.
Daytime Fatigue
Poor sleep quality compounds. Fragmented circadian signaling leaves you groggy, unfocused, and reaching for caffeine.
Eye Strain & Headaches
PWM flicker from display dimming and harsh blue wavelengths contribute to digital eye strain, especially at night.
Three steps to healthier light
CircadianShield runs quietly in your menu bar and adapts your display automatically.
Install
Download CircadianShield and drag it to your Applications folder. No account required.
Set Your Location
Choose from 130+ city presets or let CircadianShield auto-detect your coordinates for precise solar tracking.
It Just Works
Your display color temperature adjusts automatically as the sun moves. Warm at night, bright in the morning.
Everything your eyes need
Built on real circadian science, not just a color tint slider.
Solar-Based Filtering
Tracks your sun's real elevation through 11 twilight phases with smooth sigmoid transitions between 1800K and 6500K.
Morning Boost
A 6500K wake-up boost synced to civil dawn helps suppress residual melatonin and jumpstart your alertness.
20-20-20 Break Timer
Every 20 minutes, look at something 20 feet away for 20 seconds. Smart pause during video calls and full-screen apps.
Circadian Health Score
An A–F grade based on your light exposure patterns and timing. Track your light debt and improvement over time.
Ambient Soundscapes
Six nature themes — ocean, rain, forest, creek, wind, night crickets — generated mathematically on-device and synced to solar phases.
Light Debt Tracking
Measures post-sunset melanopic exposure and tracks recovery via morning sunlight logging. See your circadian debt accumulate and pay it back.
Health Dashboard
Daily scores, 7/30/90-day trend charts, sleep quality tracking, and screen time history. 365 days of circadian health data stored locally.
11 Display Modes
Auto, Movie, Reading, Coding, Presentation, Gaming, Biohacker, Sunglasses, Dark, Custom, and Disabled. One click in the menu bar.
Per-App Profiles
Color-accurate mode for Photoshop, cinema mode for Netflix, coding mode for Xcode. Each app gets the right filter.
PWM Flicker Protection
Software dimming overlay eliminates the invisible flicker from hardware PWM backlight dimming that causes headaches.
Smart Automation
Auto-disable in fullscreen, flow detection that defers breaks, inactivity pause, video call detection, and DST smoothing.
100% On-Device
No cloud, no accounts, no telemetry. Solar calculations, health data, and soundscapes all run locally on your Mac.
Built on melanopic EDI & CIE S 026
CircadianShield uses the CIE S 026:2018 standard to calculate melanopic equivalent daylight illuminance — the metric that actually predicts circadian impact. Not just "blue light filtering."
Read the ScienceNight Shift vs f.lux vs Circadian Shield
See why a simple color tint is not enough for real circadian protection.
| Feature | Night Shift | f.lux | Circadian Shield |
|---|---|---|---|
| Color temperature shift | Basic slider | Automatic | 11 specialized modes |
| Circadian science (CIE S 026) | No | Partial | Full implementation |
| Health dashboard | No | No | Circadian score + trends |
| Light debt tracking | No | No | Post-sunset + recovery |
| Soundscapes | No | No | 6 solar-synced themes |
| Per-app control | No | Limited | Per-app profiles |
| Deep enough warmth | No (common complaint) | Partial | Down to 1800K |
| Active development | Minimal | Stagnant | Active (2026) |
Read more: Why Night Shift Isn't Warm Enough (And What Actually Works)
Available on your devices
Protect your circadian rhythm today
14-day free trial with full Pro features. No credit card required to download.