Not all light is the same, even when it looks similar to your eyes. The difference between sunlight and artificial light isn't just where it comes from — it's the entire shape of the signal your body is receiving.
Sunlight is a moving target, on purpose
Natural daylight isn't static. Its color temperature and wavelength mix shift constantly — by time of day, season, and location. All wavelengths peak around midday, when your body is meant to be most active. As the sun sets, that light shifts warmer and dimmer, with blue wavelengths dropping off first. For most of human history, once the sun went down, firelight — dominated by red and infrared wavelengths — was the only light source available, and that kind of light does very little to suppress melatonin.
That gradual, predictable shift is itself a signal. Your circadian rhythm evolved to read it.
Artificial light doesn't shift — that's the problem
Light bulbs, screens, and household lighting don't dim and warm the way sunlight does. They hold a fixed spectrum regardless of the time of day, heavy on blue and green wavelengths whether it's 9am or 11pm. Your body doesn't have a separate signal for "it's an LED, ignore this" — it reads blue light as blue light, and blue light at night reads as "stay awake" no matter the source.
Roughly, different wavelengths carry different functional signals to the body: blue light drives alertness, green light supports activity, and red light is associated with winding down and recovery. Artificial lighting after dark delivers exactly the wrong ratio of these — heavy on the wake-up signal, light on the wind-down one — at precisely the time your body needs the opposite.
Why this matters more at night than during the day
The same blue light that helps you focus at 10am works against you at 10pm, because it's arriving out of sync with the rhythm your body expects. Daytime blue light exposure is balanced by everything else happening in a natural light cycle. Nighttime blue light exposure is isolated, unbalanced, and directly suppresses melatonin release — which is why screen time before bed has such an outsized effect on sleep quality compared to the same light exposure earlier in the day.
What actually helps
You can't turn your evenings into firelight, but you can control how much of that mismatched artificial light actually reaches your eyes once it's time to wind down. That's the whole premise behind VERALAS: real, complete darkness from our silk sleep masks, paired with a lavender routine that gives your body a consistent, reliable cue that the day is actually over — the same kind of clear signal sunset used to provide on its own.
Sources: research on circadian photobiology and light wavelength effects via Physiological Reports (Wiley); established research on blue light and melatonin suppression.