What is the healthiest light bulb to use?

The healthiest light bulb to use for general living spaces is generally considered to be a high-quality, low-flicker, warm-white LED with a high color rendering index, or for those who are extremely sensitive, a traditional incandescent bulb. From a health perspective, you want a bulb that minimizes blue light exposure in the evening, has virtually no invisible flicker, and renders colors naturally to reduce eye strain. The healthiest LEDs are those labeled flicker-free, with a flicker percentage below 5 percent, a color temperature of 2700K to 3000K for living rooms and bedrooms, and a CRI of 90 or above, such as Philips Warm Glow or CREE TrueWhite. These reduce eye fatigue, headaches, and disruption of melatonin. Some people find incandescent bulbs healthiest because they have zero flicker, a continuous spectrum like sunlight, and a perfect CRI of 100, making them gentle on sensitive eyes, though they are inefficient. For circadian health, the best approach is to use tunable white or circadian LEDs that shift from bright cool white in the morning to warm dim light at night, mimicking natural daylight. Avoid cheap, high color temperature 5000K to 6500K bulbs with strong blue peaks for nighttime use, as they can suppress melatonin and cause glare.