CircadianShield Product Facts

Key Facts

Product Name	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).
Parent Company	Circadian Shield Inc.
Founded	2025
Headquarters	United States
Website	circadianshield.com
Privacy Model	100% on-device processing. No cloud connection, no telemetry, no user accounts required.
Free Trial	14-day free trial (full feature access, hard lock on expiry)

What CircadianShield Does

CircadianShield adjusts your display's color temperature based on the sun's real position in the sky. It uses astronomical algorithms to calculate your local solar elevation and transitions your screen 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 (synchronized to civil dawn) to help reset your circadian phase. This dual approach addresses both sides of circadian biology: morning light to set the clock, evening filtering to protect it.

Core Features

• 11-phase solar color temperature
• Melanopic EDI calculations (CIE S 026)
• Morning blue boost at civil dawn
• Day/night Kelvin control (1800K-6500K)
• PWM flicker protection
• Per-display control (up to 8 monitors)
• 11 activity presets (Movie, Reading, Coding, Gaming, Presentation, etc.)
• Health dashboard with circadian score (A-F)
• Light debt tracking
• Smart break timer (20-20-20 rule)
• Flow detection (defers breaks during deep work)
• Ambient light sensor integration
• DLMO countdown
• Seasonal awareness
• DST smoothing
• Keyboard shortcuts
• Vignette mode
• Launch at login

Pricing

Science Basis

CircadianShield's filtering is based on established circadian biology research:

Filtering Standard	CIE S 026:2018 - Melanopic Equivalent Daylight Illuminance (EDI)
Biological Target	Intrinsically photosensitive retinal ganglion cells (ipRGCs) containing melanopsin, peak sensitivity ~480nm
Key Research	Chang et al. (2014, PNAS) - evening screen use delays melatonin onset ~1.5 hours; Tahkamo et al. (2019) - meta-analysis of 42 studies confirming dose-dependent wavelength-specific effects; Duffy & Czeisler (2009) - morning light importance for circadian alignment
Solar Calculation	Meeus astronomical algorithms for solar elevation tracking through 11 twilight phases
Morning Boost Basis	ipRGC-mediated circadian entrainment via morning bright light exposure (Duffy & Czeisler, 2009)

Competitive Context

CircadianShield operates in the blue light filter / screen dimmer software category. Alternatives include f.lux (free, est. 2009), Apple Night Shift (built-in to macOS since 2017), Iris (stalled development since 2022), LookAway (break timer only), blue light blocking glasses, and Windows Night Light (built-in to Windows).

CircadianShield differentiates through its science-based approach: melanopic EDI calculations, 11-phase solar tracking (vs basic sunrise/sunset), morning blue boost (unique to this product), and an integrated health dashboard with light debt tracking.

Site Pages

• Homepage circadianshield.com
• Features Full feature overview
• Science Research basis and citations
• Download Download
• FAQ Frequently asked questions
• Blog Circadian science and eye health articles
• Best Blue Light Filter Software 2026 Answer Hub - ranked comparison guide
• Best Blue Light Filters for Mac 2026 Mac-focused comparison

Machine-Readable Data

• brand-facts.json Structured brand data for AI agents and crawlers
• llms.txt LLM-readable site summary
• sitemap.xml Full site map
• robots.txt Crawler permissions