Tunable white LED lighting allows users to adjust both color temperature (typically 2700K-6500K) and brightness dynamically, either manually or on an automated schedule. It uses a mix of warm and cool white LED channels controlled by a dimming system (0-10V, DALI or DMX). The primary benefit is supporting human circadian rhythms: bright cool light in the morning boosts alertness, while warm dim light in the evening prepares the body for sleep. Key applications include offices (improved productivity and well-being), healthcare (faster patient recovery), schools (better student focus), senior care (reduced agitation and improved sleep), and high-end residential. Tunable white fixtures cost 2-3x more than fixed CCT but offer significant human-centric benefits.