Blue light has been shown to affect alertness in the evening in 13 young men here https://journals.physiology.org/doi/full/10.1152/japplphysiol.00165.2011 https

Blue light has been shown to affect alertness in the evening in 13 young men here https://journals.physiology.org/doi/full/10.1152/japplphysiol.00165.2011 https://journals.physiology.org/doi/full/10.1152/japplphysio... Would be interested in studies refuting this.