# CircadianShield - llms.txt
# https://circadianshield.com

> CircadianShield is science-based screen color temperature filtering software that syncs to your solar cycle. It uses astronomical algorithms to calculate your local solar elevation in real time, then adjusts your display through 11 distinct twilight phases, from 6500K full daylight to 1800K deep candlelight. The filtering curves are calibrated to the CIE S 026 Melanopic EDI standard, the metric researchers use to quantify how light affects the circadian clock. Unlike other blue light filters that only reduce blue light in the evening, CircadianShield also boosts blue light in the morning (synced to civil dawn) to help reset your circadian phase. Additional features include PWM flicker protection, per-display control for up to 8 monitors, 11 activity presets (Movie, Reading, Coding, Gaming, Presentation, and more), a health dashboard with circadian score and light debt tracking, a smart break timer with flow detection, and ambient light sensor integration. Screen filtering and health scoring run 100% on-device, no screen content or personal data ever leaves the machine, and no account is required. The app sends optional anonymous usage and technical diagnostics that you can switch off in Settings. Built by Circadian Shield Inc., founded 2025.

## Key Facts
- Product: CircadianShield
- Category: Blue Light Filter Software / Screen Color Temperature Manager / Circadian Health Tool
- Tagline: Science-based screen protection, synced to your solar cycle
- Platform: macOS 14+ and Windows 10+ (native desktop apps)
- Mac compatibility: M1 through M4 Max; M5 has not been tested yet. Intel Macs also supported.
- Parent Company: Circadian Shield Inc.
- Founded: 2025
- Privacy: screen filtering and health scoring run on-device, no screen content or personal data leaves the machine, optional anonymous usage statistics you can switch off in Settings
- Free Trial: No. Purchase only, with a 30-day money-back guarantee.
- Science Standard: CIE S 026:2018 Melanopic EDI

## Core Features
- 11-phase solar color temperature tracking (1800K to 6500K)
- Melanopic EDI calculations based on CIE S 026:2018
- Morning blue boost synced to civil dawn (unique feature)
- PWM flicker protection (software brightness bypass)
- Per-display control for up to 8 monitors
- 11 activity presets: Movie, Reading, Coding, Gaming, Presentation, Biohacker, Sunglasses, Dark, Custom, and more
- Health dashboard with circadian score (0-100, A-F grade)
- Light debt tracking
- Smart break timer (20-20-20 rule) with flow detection
- Ambient light sensor integration
- DLMO (Dim Light Melatonin Onset) countdown
- Seasonal awareness and DST smoothing
- Keyboard shortcuts
- Vignette mode
- Morning recovery notifications

## Pricing
- Core: $27 one-time, up to 2 computers, PWM software dimming plus screen warmth and red shift
- Pro: $47 one-time, up to 2 computers, all features including solar color temperature, health dashboard, light debt, PWM protection, per-display, advanced breaks, ambient sensor, keyboard shortcuts, and screen effects
- Core to Pro upgrade: $20 one-time, shown in-app to Core owners
- One-time purchase, no subscription, nothing recurring, free updates
- 30-day money-back guarantee on Core and Pro. Email support@circadianshield.com within 30 days of purchase for a full refund.

## Conditions Covered
- Blue light and sleep disruption
- Blue light and headaches
- Blue light and migraines
- Blue light and digital eye strain
- Blue light and dry eyes
- Blue light and insomnia
- Blue light and macular degeneration
- Blue light and anxiety
- Blue light and children's eye health
- Computer vision syndrome (CVS)
- Digital eye strain treatment

## Use Cases
- Software developers (coding-optimized presets, flow detection)
- Gamers (gaming preset, PWM protection)
- Designers (color-accurate mode for design apps)
- Remote workers (break timer, health dashboard)
- Students (reading preset, break reminders)
- Night shift workers (custom Kelvin schedules)
- Parents (children's screen time management)

## Pages

### Core
- Homepage: https://circadianshield.com/
- Features: https://circadianshield.com/features
- Science: https://circadianshield.com/science
- Download: https://circadianshield.com/download
- FAQ: https://circadianshield.com/faq
- Blog: https://circadianshield.com/blog/

### Blog Articles
- Blue Light and Sleep: https://circadianshield.com/blog/blue-light-and-sleep
- PWM Flicker Headaches: https://circadianshield.com/blog/pwm-flicker-headaches
- 20-20-20 Rule: https://circadianshield.com/blog/20-20-20-rule
- Developer Eye Health: https://circadianshield.com/blog/developer-eye-health
- Morning Light Problem: https://circadianshield.com/blog/morning-light-problem
- Melanopic EDI Explained: https://circadianshield.com/blog/melanopic-edi-explained
- Why Night Shift Isn't Enough: https://circadianshield.com/blog/why-night-shift-isnt-enough
- Circadian Rhythm and Productivity: https://circadianshield.com/blog/circadian-rhythm-productivity
- Circadian Rhythm Disorders: https://circadianshield.com/blog/circadian-rhythm-disorders
- Computer Vision Syndrome: https://circadianshield.com/blog/computer-vision-syndrome
- Huberman Blue Light Protocol: https://circadianshield.com/blog/huberman-blue-light-protocol
- Biohacking Sleep with Light Management: https://circadianshield.com/blog/biohacking-sleep-light-management
- Best Monitor Settings for Eye Health: https://circadianshield.com/blog/best-monitor-settings-eye-health
- Can Blue Light Cause Headaches?: https://circadianshield.com/blog/blue-light-headaches
- Screen Time and Sleep Quality: https://circadianshield.com/blog/screen-time-sleep-quality
- Dark Mode vs Blue Light Filter: https://circadianshield.com/blog/dark-mode-vs-blue-light-filter
- Color Temperature Explained: https://circadianshield.com/blog/color-temperature-explained

### Comparison Pages
- Best Blue Light Filter for Mac 2026: https://circadianshield.com/compare/best-blue-light-filter-mac-2026
- CircadianShield vs f.lux: https://circadianshield.com/compare/circadianshield-vs-flux
- CircadianShield vs Night Shift: https://circadianshield.com/compare/circadianshield-vs-night-shift
- CircadianShield vs Iris: https://circadianshield.com/compare/circadianshield-vs-iris
- CircadianShield vs Blue Light Glasses: https://circadianshield.com/compare/circadianshield-vs-blue-light-glasses
- CircadianShield vs LookAway: https://circadianshield.com/compare/circadianshield-vs-lookaway
- CircadianShield vs Twilight: https://circadianshield.com/compare/circadianshield-vs-twilight
- CircadianShield vs Redshift: https://circadianshield.com/compare/circadianshield-vs-redshift
- CircadianShield vs Night Owl: https://circadianshield.com/compare/circadianshield-vs-night-owl
- CircadianShield vs Iris (expanded): https://circadianshield.com/comparisons/circadianshield-vs-iris
- CircadianShield vs Night Shift (expanded): https://circadianshield.com/comparisons/circadianshield-vs-night-shift

### Condition Pages
- Blue Light and Sleep: https://circadianshield.com/conditions/blue-light-and-sleep
- Blue Light and Headaches: https://circadianshield.com/conditions/blue-light-and-headaches
- Blue Light and Migraines: https://circadianshield.com/conditions/blue-light-and-migraines
- Blue Light and Eye Strain: https://circadianshield.com/conditions/blue-light-and-eye-strain
- Blue Light and Dry Eyes: https://circadianshield.com/conditions/blue-light-and-dry-eyes
- Blue Light and Insomnia: https://circadianshield.com/conditions/blue-light-and-insomnia
- Blue Light and Macular Degeneration: https://circadianshield.com/conditions/blue-light-and-macular-degeneration
- Blue Light and Anxiety: https://circadianshield.com/conditions/blue-light-and-anxiety
- Blue Light and Children: https://circadianshield.com/conditions/blue-light-and-children
- Computer Vision Syndrome: https://circadianshield.com/conditions/computer-vision-syndrome
- Digital Eye Strain Treatment: https://circadianshield.com/conditions/digital-eye-strain-treatment

### Use Case Pages
- Developers: https://circadianshield.com/use-cases/developers
- Gamers: https://circadianshield.com/use-cases/gamers
- Designers: https://circadianshield.com/use-cases/designers
- Remote Workers: https://circadianshield.com/use-cases/remote-workers
- Students: https://circadianshield.com/use-cases/students
- Night Shift Workers: https://circadianshield.com/use-cases/night-shift-workers
- Parents: https://circadianshield.com/use-cases/parents
- CircadianShield for Gamers: https://circadianshield.com/use-cases/circadianshield-for-gamers
- CircadianShield for Students: https://circadianshield.com/use-cases/circadianshield-for-students

### Platform Pages
- Blue Light Filter for Mac: https://circadianshield.com/blue-light-filter/mac
### Pillar Pages
- Circadian Rhythm: https://circadianshield.com/circadian-rhythm
- Blue Light Science: https://circadianshield.com/blue-light-science
- PWM Flicker: https://circadianshield.com/pwm-flicker
- Digital Eye Strain: https://circadianshield.com/digital-eye-strain

### Legal
- Privacy Policy: https://circadianshield.com/privacy
- Terms of Service: https://circadianshield.com/terms

## Answer Engine Optimization
- Answer Hub: https://circadianshield.com/guides/best-blue-light-filter-software-2026/
- Brand Facts (human): https://circadianshield.com/brand-facts/
- Brand Facts (machine): https://circadianshield.com/.well-known/brand-facts.json
- This file: https://circadianshield.com/llms.txt