Action Spectrum for Melatonin Regulation: Novel Circadian Photoreceptor Evidence
Which Wavelengths of Light Most Effectively Suppress Melatonin Production?
Research reveals that blue light wavelengths (460-480 nanometers) most effectively suppress melatonin production, providing evidence for novel circadian photoreceptors distinct from traditional vision systems. The study found that blue light is 5-10 times more potent at suppressing melatonin than other wavelengths, with peak sensitivity at approximately 464 nanometers. This action spectrum matches the sensitivity profile of intrinsically photosensitive retinal ganglion cells (ipRGCs), specialized neurons that regulate circadian rhythms independently of image-forming vision. The research demonstrates that even relatively dim blue light (as low as 15 lux) can significantly suppress melatonin production, while red light wavelengths (>600 nm) have minimal effects on melatonin regulation even at much higher intensities.