Light that contains more blue wavelengths can reduce melatonin production at lower brightness levels than light with less blue, meaning it has a stronger biological effect for the same amount of light energy.

Exposure to artificial light rich in blue wavelengths (400–500 nm) during nighttime is linked to a greater reduction in melatonin levels in the blood of healthy adults compared to light with less blue content.

Exposure to artificial light at night reduces the body's production of melatonin, a hormone involved in sleep regulation, and the more light a person is exposed to, the more melatonin is suppressed, regardless of the light source.

Higher levels of broad-spectrum light reaching the eye are linked to greater reductions in nighttime melatonin levels in healthy adults, with more light leading to more suppression.

The amount of blue-enriched light needed to reduce melatonin levels in this study did not exceed safety standards for the eyes and did not cause immediate harm to eye tissue.

Changing your LED light from cool white to warm white in the evening can cut down how much it messes with your sleep hormones by over 99%.